WUR Journal browser

WUR Journal browser

  • external user (warningwarning)
  • Log in as
  • The Journal Browser provides a list of more than 30,000 journals. It can be consulted by authors who wish to select a journal for publishing their manuscript Open Access. The information in this list is aggregated from several sources on a regular basis:

    • A list of journals for which the Association of Universities in the Netherlands (VSNU) has made deals with publishers, to make articles Open Access. Under these deals, corresponding authors of Dutch universities can publish their articles Open Access in the participating journals with discounts on the article processing charges (APCs).
    • A list of journals covered by the Journal Citation Reports.
    • A list of journals covered by Scopus.
    • Journals indexed in the Directory of Open Access Journals (DOAJ).
    • Lists of journals for which specific Dutch universities have made deals with publishers, to make articles Open Access. Under these deals, corresponding authors of these universities can publish their articles Open Access in the participating journals with discounts on the article processing charges (APCs). Depending on the university from which the Journal Browser is consulted, this information is shown.
    • Additional data on citations made to journals, in articles published by staff from a specific Dutch university, that are made available by that university. Depending on the university from which the Journal Browser is consulted, this information is shown.

    In the Journal Browser, a search box can be used to look up journals on certain subjects. The terms entered in this box are used to search the journal titles and other metadata (e.g. keywords).

    After having selected journals by subject, it is possible to apply additional filters. These concern no/full costs and discounts for Open Access publishing, support on Open Access publishing in journals, and the quartile to which the journal’s impact factor belongs.

    When one selects a journal in the Journal Browser, the following information may be presented:

    • General information about the selected journal such as title and ISSNs, together with a link to the journal’s website.
    • APC discount that holds for the selected journal if it is part of an Open Access deal.
    • Impact measures for the selected journal from Journal Citation Reports or Scopus. The impact measures that are shown may vary, depending on the university from which the Journal Browser is consulted. For some universities, the number of citations made to the selected journal (in articles published by staff from that university) is also shown.
    • Information from Sherpa/Romeo on the conditions under which articles from the selected journal may be made available via Green Open Access.
    • A listing of articles recently published in the selected journal.
    • For some universities, information is available on what journals have been co-cited most frequently together with the selected journal (in articles published by staff from these universities). When available, this information is presented under ‘similar journals’.




ISSN: 0044-8486 (1873-5622)
Fisheries - Marine & Freshwater Biology - Aquatic Science
APC costs unknown

Recent articles

1 show abstract
0044-8486 * * 29696250
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Kyosuke Niwa, Atsushi Kobiyama

Recent production of the marine crop Undaria pinnatifida has become unstable due to rising temperatures caused by global climate change. The cultivar HGU-1 was bred in a previous study to achieve early cultivation. A new cultivar, NW-1, was bred for improved yield and stress tolerance. This was achieved by crossbreeding using male and female gametophytes, each isolated from a single zoospore. To evaluate whether the cultivar NW-1 is superior to the previous cultivar HGU-1, we compared their growth characteristics in an Undaria farm, in the eastern Seto Inland Sea of Japan. Despite the early start of nursery cultivation, due to a high seawater temperature of 24.5 °C, many young sporophytes of NW-1 grew on strings wound around the collector, whereas most of the HGU-1 sporophytes fell from the strings. After nursery cultivation, seawater temperature during rope cultivation was remarkably higher than usual. Nevertheless, the mean total length and weight of NW-1 were 115.5 cm and 140.1 g, respectively, at the end of December. In contrast, the mean total length and weight of HGU-1, at the corresponding time, were 85.4 cm and 58.1 g, respectively. Moreover, the growth and weight of the NW-1 sporophytes were significantly higher than those of HGU-1 throughout experimental cultivation. These results demonstrate that NW-1 is an excellent cultivar with a high yield and high-temperature tolerance.

2 show abstract
0044-8486 * * 29696251
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Velmurugu Puvanendran, Ingrid Lein, Rama Bangera, Atle Mortensen, Anders Thorsen

Early maturation has been one of the biological bottlenecks of commercializing Atlantic cod culture. To overcome the bottleneck, production of sterile fish through triploidy and other molecular techniques have been suggested and attempted. Although studies have been carried out on triploid performance of Atlantic cod, no studies have been conducted to see the performance of triploid fish at family level. We produced 29 triploid sibling families using standard hydrostatic pressure technique of newly fertilized eggs with parallel, untreated diploid families. Larvae were reared in separate tanks using standard rearing protocols until reaching 20 g and were PIT tagged. PIT tagged juveniles were transferred to sea cages in duplicate. At 34 months post-hatch, all the fish were sampled and body weight, liver weight and gonadal weight were recorded. Results showed that significant family differences exist between diploid and triploid families in gonadal development, especially for the females. Fish from triploid families had significantly smaller gonadosomatic index than fish from diploid families, but diploid families were heavier than the triploid families. Our result highlight the need for considering a parallel strategy for triploid family selection within the conventional diploid breeding program to exploit the existing variation in triploid performance.

3 show abstract
0044-8486 * * 29696252
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Kang Chen, Xiao-Qiu Zhou, Wei-Dan Jiang, Pei Wu, Yang Liu, Jun Jiang, Sheng-Yao Kuang, Ling Tang, Wu-Neng Tang, Lin Feng

Phosphorus (P) is an important and essential mineral for fish. To investigate the effects of dietary P on gill immune and physical barrier function in grass carp (Ctenopharyngodon idella), fish were fed six graded levels of dietary available P (0.95–8.75 g/kg diet) for 60 days, and then sampled 3 days after a challenge test (exposure to water containing Flavobacterium columnare; 1.0 × 108 colony-forming units (cfu)/ml for 3 h). P deficiency resulted in a decline in gill antimicrobial compound production, and liver-expressed antimicrobial peptide 2A (LEAP-2A), LEAP-2B, hepcidin and β-defensin-1 transcript abundance. P deficiency also decreased target of rapamycin transcript and protein expression and increased nuclear factor kappa B p65 mRNA expression, which because of their association with anti-inflammatory and pro-inflammatory cytokine gene expression, respectively, suggesting that P deficiency increased post-infection gill inflammation and could impair immune barrier function. Furthermore, P deficiency: (1) Enhanced Fas ligand /caspase-8 death receptor and Bcl-2associated X protein/apoptotic protease activating factor-1/caspase-9 mRNA expression (which is indicative of increased apoptosis). (2) Inhibited Kelch-like-ECH-associated protein 1b/NF-E2-related factor 2 mRNA expression, decreased the expression of antioxidant enzyme transcript levels and activities (with the exception of CuZnSOD mRNA expression), and increased ROS, malondialdehyde and protein carbonyl levels. This data suggests that protection against ROS-related damage was compromised with P deficiency. (3) Up-regulated myosin light chain kinase transcript levels, a response that was associated with the down-regulation zonula occludens 1 (but not ZO-2), occludin and claudin (except claudin-12) mRNA levels. This latter result suggesting that tight junction functional integrity (and thus, gill physical barrier function) was impaired. These data, combined with the fact that P deficiency led to opercular deformation and gill rot syndrome, suggest that insufficient dietary levels of this mineral (i.e. below ~5.75 mg/kg P) could increase the susceptibility of fishes to water borne pathogens.

4 show abstract
0044-8486 * * 29696253
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): C.M.E. Lajoie, O.P. Love, D.D. Heath, J.W. Heath, T.E. Pitcher

In British Columbia, Atlantic salmon (Salmo salar) are the top finfish aquaculture export of the province, although native Chinook salmon (Oncorhynchus tshawytscha) are also farmed locally. Few commercial facilities rear Chinook salmon, limiting the availability and development of their broodstocks, potentially reducing the ability to improve product quantity and quality. Due to the potential for inbreeding in these stocks, a need to determine whether product quantity and quality can be improved through outbreeding with wild populations exists. In this study, we examined the effects of outbreeding on farmed salmon by comparing product quantity and quality metrics in six experimental populations of outbred (wild × farmed) Chinook salmon and one farmed (control) population. Specifically, we measured fillet yield, slaughter yield, lipid content and flesh colour score in three-year old market-sized salmon immediately post-slaughter. We found significant differences across populations for slaughter yield, fillet yield and flesh colour score but found no differences across populations in lipid content. For flesh colour score, slaughter and fillet yield, the control farmed population performed similarly to the highest performing outbred populations. These results suggest that outbreeding inbred farmed populations with wild populations can maintain high product quality while adding new genes to a population.

5 show abstract
0044-8486 * * 29696260
Publication date: Available online 15 March 2019

Source: Aquaculture
Author(s): Xiaowen Chen, Jun Wang, Xin Hou, Wucheng Yue, Zhihua Li, Chenghui Wang

Aerial respiration is a restricting factor for aquatic species to survive out of water. The Chinese mitten crab Eriocheir sinensis, an economic aquatic crustacean species capable of aerial respiration, can survive for a long time out of water. However, the genetic mechanism underlying the aerial respiration of crustacean is still lacking. In this study, we conducted a comparative transcriptome analysis among gill tissues collected from E. sinensis exposed to an environment without water. Results showed that genes associated with moisture maintenance and water transport were upregulated, while genes associated with metabolism and ammonium transmembrane transport were downregulated in E. sinensis out of water. Our results suggested that E. sinensis improves its water-holding capacity and reduces its metabolism by regulating associated genes to maintain effective aerial respiration, and provided valuable genetic resources and novel insights into the hypoxia tolerance and aerial respiration of crustaceans. This study may also serve as a reference for the commercial transportation of E. sinensis.

6 show abstract
0044-8486 * * 29696261
Publication date: Available online 15 March 2019

Source: Aquaculture
Author(s): Kelli Anderson, J. Adam Luckenbach, Yoji Yamamoto, Abigail Elizur

In salmonids, exposure to elevated temperature impairs oogenesis. As such, there is a need to understand the molecular mechanisms that underpin this process, and develop mitigation strategies that maintain or rescue reproductive development in broodstock. In this study, follicle stimulating hormone (Fsh) and/or insulin-like growth factor 1 (Igf1) treatment were assessed for their ability to promote reproductive function at 14 and 22 °C in ovarian follicles from coho salmon in vitro. Maintenance at 22 °C resulted in the downregulation of fsh receptor, 17α-hydroxylase/C17,20-lyase and p450 aromatase a (cyp19a1a), and connexin 34.3 (cx34.3). While combined treatment with Fsh and Igf1 stimulated the expression of cyp19a1a at 14 °C, this treatment was not effective at 22 °C. Upregulation of cx34.3 occurred in response to treatments that contained Igf1 regardless of temperature, and there is evidence to suggest that apoptosis was inhibited to some extent at 22 °C following combined treatment with Fsh and Igf1. This study demonstrates the thermal impairment of key reproductive genes, and highlights the potential for novel hormone treatments to rescue oogenesis in salmonids.

7 show abstract
0044-8486 * * 29696262
Publication date: Available online 15 March 2019

Source: Aquaculture
Author(s): Bong Jung Kang, Sun-Hye Bae, Tomoya Suzuki, Shuhei Niitsu, Marcy N. Wilder

Eyestalk ablation, which is a method for the removal of the source of vitellogenesis-inhibiting hormone (VIH), is frequently used in Litopenaeus vannamei in order to stimulate ovarian maturation and spawning in captivity. In this study, we assessed the effects of vih silencing using double-stranded RNA (dsRNA) in L. vannamei females. The relative expression levels of vitellogenin (vg) and vih were analyzed in the ovary and eyestalks, respectively, and levels of Vg and VIH in hemolymph were quantified at 10 and 20 days following injection with VIH-dsRNA, green fluorescent protein (GFP)-dsRNA (a non–VIH-related dsRNA), or Tris-EDTA (TE) buffer. Expression of vih in the eyestalks was significantly suppressed at 10 and 20 days after VIH-dsRNA injection. Hemolymph VIH levels were significantly increased at 10 days after VIH-dsRNA injection and then decreased to initial levels. However, there were no significant differences in the levels of Vg in hemolymph or vg mRNA in the ovary.

8 show abstract
0044-8486 * * 29696263
Publication date: Available online 15 March 2019

Source: Aquaculture
Author(s): Adriána Fečkaninová, Jana Koščová, Dagmar Mudroňová, Petra Schusterová, Ivana Maruščáková, Peter Popelka

An effective probiotic must comply with criteria, which determines its effect. The aim of this work was to isolate lactic acid bacteria (LAB) from the intestinal content of rainbow trout (Oncorhynchus mykiss), subsequently potentially used as probiotics in order to improve health status of fish during fish farming. Selection criteria were used to obtain suitable probiotic candidates for aquaculture of salmonid. A total of 6 lactic acid bacteria isolated from intestines of rainbow trout belonging to the genus Lactobacillus were included in this study, and encompassed the following species: L. plantarum (n = 3), L. fermentum (n = 2), and L. brevis (n = 1). Antimicrobial susceptibility test has been performed on the basis of Guidance on the assessment of bacterial susceptibility to antimicrobials of human and veterinary importance by the EFSA. Sensitivity or intrinsic resistance of the isolated LAB to a recommended set of antibiotics make them safe for use as probiotics in aquaculture. All six autochthonous isolates showed the antagonistic activity against both salmonid pathogens Aeromonas salmonicida subsp. salmonicida CCM 1307 and Yersinia ruckeri CCM 6093. Determined in vitro survival conditions in the gastrointestinal tract of rainbow trout, and taking into account the previous results, two isolates - Lactobacillus plantarum (R2) and Lactobacillus fermentum (R3), which showed the highest level of tolerance to different pH values, bile, temperature, and the best growth properties, were selected as candidates for probiotics. These two strains have been sent to the Czech Collection of Microorganisms (CCM) of Masaryk University in Brno for purposes of Patent Procedure under the Budapest Treaty.

9 show abstract
0044-8486 * * 29696264
Publication date: Available online 14 March 2019

Source: Aquaculture
Author(s): Cahya Fusianto, Paul M. Hick, Joy A. Becker

The genus Megalocytivirus (MCV) includes Infectious spleen and kidney necrosis virus (ISKNV) and red seabream iridovirus (RSIV) which are listed by the World Organization for Animal Health (OIE). MCV has a broad host range and can be present as a persistent subclinical infection in some fish. Australia is considered free from MCV and important aquaculture and wild fisheries are at risk. Consequently, biosecurity measures are implemented to ameliorate transmission pathways through imported ornamental fish which include certification of freedom from infection with MCV. Evaluation of practical and cost effective disinfection protocols suitable for recirculating aquaculture facilities is an important aspect of the biosecurity plan to facilitate eradication in the event of early detection of an outbreak. An authentic sample matrix was prepared by in vivo amplification of ISKNV in Murray cod (Maccullochella peelii) and the biological load of a clarified tissue homogenate was standardized by addition of 10% v/v foetal bovine serum. In the absence of a cell culture system for ISKNV, a bioassay was used to assess infectivity after disinfection. A cellulose membrane buffer exchange device was used to remove residual disinfectants before intraperitoneal injection of juvenile Murray cod. Fish were maintained in 100 L aquaria at 23 °C and observed for clinical signs over 14 days. Each bioassay was conducted in duplicate tanks with 6 to 19 fish per tank. A positive assay was defined by an increase in ISKNV DNA quantified by qPCR in any fish from a subsample of challenged fish collected at 7 d or those remaining at 14 d. Negative bioassays were defined by the absence of ISKNV DNA in all fish at the both sampling times. Clinical disease and amplified viral DNA was detected after injection of a dilute positive control, indicating greater analytical sensitivity compared to qPCR (with a detection limit of 100 copies per reaction). Further, the system was used to demonstrate that ISKNV can remain infectious in aquaria without fish for at least 48 h at 25 °C. Effective disinfection measures included: heating to 65 °C for 20 min; pH 3; pH 11; 1% Virkon™; 1000 ppm sodium hypochlorite and benzalkonium chloride at the recommended concentration and contact time. These data can be interpreted to provide effective disinfection protocols for MCV in a wide variety of disease control scenarios.

10 show abstract
0044-8486 * * 29696265
Publication date: Available online 14 March 2019

Source: Aquaculture
Author(s): Amal Biswas, Hideo Araki, Tetsuo Sakata, Toshihiro Nakamori, Kenji Takii

Two trials were carried out to determine the optimal replacement level of fish meal (FM) by soy protein concentrate (SPC) derived from soymilk without supplementation of indispensable amino acids (IAAs) or palatability enhancers and whether phytase supplementation can help to replace more SPC in diet of juvenile red sea bream, Pagrus major. In Trial 1, five isoenergetic diets were formulated: 67% FM as protein source in the control diet (C), and FM was replaced by 60 (SPC60), 70 (SPC70), 80 (SPC80) and 100% (SPC100) by SPC. In Trial 2, diets C and SPC80 were the same as in Trial 1, and phytase was supplemented in SPC80 at 1000 (P1), 2000 (P2), 3000 (P3) and 4000 (P4) FTU/kg diet. Thirty (ca. 23 g) and 20 fish (ca. 21 g) were randomly distributed into each fifteen and eighteen 300 L indoor tanks in Trial 1 and 2, respectively. Fish in both trials were fed two times daily until apparent satiation for 10 weeks. At the end of both trials, feces were collected after feeding with chromic oxide (Cr2O3) mixed diets. In Trial 1, there were no significant differences in final mean weight, specific growth rate (SGR), daily feeding rate (DFR), feed efficiency (FE), condition factor (CF), and retention efficiency of protein, lipid and energy until 70% (SPC70) FM replacement by SPC (P > .05). However, 80% FM replacement significantly reduced final mean weight, FE and lipid retention efficiency compared with group C (P < .05). There were no significant differences in plasma constituents, except total cholesterol level. In Trial 2, phytase was supplemented in SPC80 to determine whether it helps to stimulate growth up to the level of the control group. Fish fed SPC80 once again displayed significantly lower final mean weight, SGR, FE, phosphorus (P) digestibility, and retention efficiency of protein, lipid, energy and P compared with control group (P > .05). Final mean weight, FE, P digestibility, and retention efficiency of protein, lipid and P were significantly improved in fish fed diet P2 (phytase at 2000 FTU/kg diet) compared with those fed diet SPC80. However, phytase supplementation did not stimulate the growth up to the level of group C. The results demonstrated in juvenile red sea bream that 70% of FM can be replaced by SPC derived from soymilk without supplementation of IAAs and palatability enhancers.

11 show abstract
0044-8486 * * 29696266
Publication date: Available online 13 March 2019

Source: Aquaculture
Author(s): Emerson Giuliani Durigon, Ana Paula Gottlieb Almeida, Gabriela Tomas Jerônimo, Bernardo Baldisserotto, Maurício Gustavo Coelho Emerenciano

Biofloc technology (BFT) system is increasing around the world and Nile tilapia is suggested as the major fish species for such technology. The objective of this study was to evaluate diets with different levels of digestible protein (22, 26 and 30% DP) and digestible energy (3000, 3150 and 3300 kcal kg−1) for Nile tilapia juveniles raised in brackish biofloc system water (10 ppt) and its effects on the activity of digestive enzymes and the presence of ectoparasites in the gills. Tilapia juveniles (1.25 ± 0.15 g of initial weight) were stocked in thirty-two experimental units (100 L tanks) with 15 fish per tank. After 42 days fish were harvested, sampled and analyzed. The pepsine (stomach) and trypsine (intestine) activities significantly increased according to the increase of dietary levels. For both cases the higher activity was observed in 30% DP treatment (P < 0.05), with (pepsine) and without interaction (trypsine) with digestible energy levels. The opposite trend was observed for chymotripsine activity (intestine), in which 22% DP presented the higher activity, with significant interaction with energy levels. The higher activity for intestinal lipase activity was observed in 3150 kcal kg−1. No difference was found for ectoparasite analyses in gills between the treatments. Although in all treatments monogea type was found (70–90% of prevalence), the number of parasites per fish was low in all treatments (<1.6 parasites fish−1). The results suggested that differences in dietary digestible protein and digestible energy affected the activity of digestive enzymes in Nile tilapia juveniles raised in biofloc with 10 ppt of salinity. On the other hand, biofloc system did not promote ectoparasite spread even with low dietary levels of digestible protein and digestible energy.

12 show abstract
0044-8486 * * 29696267
Publication date: Available online 12 March 2019

Source: Aquaculture
Author(s): Guozhi Luo, Zefeng Liu, Lina Shao, Hongxin Tan

Biofloc technology involves manipulation of the C/N ratio to convert toxic nitrogenous wastes into useful microbial protein and helps improve the water quality in a closed system. Poly-β-hydroxybutyric (PHB) has been demonstrated to have positive effects on aquatic animals in an aquaculture system. A 40-day lab scale trial was carried out to investigate the potential of PHB as an additional carbohydrate for a shrimp Litopenaeus vannamei bioflocs nursery in brackish water. Three methods of carbohydrate supplementation were investigated. The first method was the addition of glucose daily at a percentage of 75% of the feed (GLU-group). The second method was the addition of PHB plus glucose; when the total ammonia nitrogen (TAN) level above 2 mg L−1 was observed, glucose was added, 6 g C to 1 g TAN (PHB + GLU-group). The third method was the addition of PHB only (PHB-group). During the 40-d trial, most of the ratios of dissolved organic carbon to total ammonium nitrogen (DOC/TAN) were maintained at 20 in the three groups. The average concentration of TAN in the PHB + GLU-group (0.23 ± 0.19 mg L−1) was significantly lower than those of the GLU-group (0.28 ± 0.26 mg L−1) and the PHB-group (0.30 ± 0.33 mg L−1) (P < .05). The average concentration of nitrite nitrogen in the PHB-group (0.16 ± 0.24) was significantly lower than those of the GLU-group and the PHB-group (P < .05). The concentrations of TAN and nitrite nitrogen from the PHB + GLU-group were more stable than those from the PHB-group and GLU-group. Nitrate nitrogen accumulated, as expected, in the three groups, and no significant differences were observed (P > .05). The survival rate and final weight in the PHB + GLU group were significantly higher than those of the other groups (P < .05). The food conversion ratio of the PHB group (1.52 ± 0.23) was significantly lower than those of the other groups. Taken together, our results showed that PHB is a favorable and convenient additional carbohydrate for shrimp Litopenaeus vannamei biofloc nurseries in brackish water. PHB + GLU was the best carbohydrate supplementation method.

13 show abstract
0044-8486 * * 29696268
Publication date: Available online 12 March 2019

Source: Aquaculture
Author(s): Letícia E. Fantini, Ruy A.C. Corrêa Filho, Thiago X. Martins, Laice M. Laice, Guilherme N. Seraphim, André Luiz N. Silva, Terry Hanson, Jayme A. Povh

This study was undertaken to compare the growth curves of native fish cachara (Pseudoplatystoma reticulatum) and of the cachapinta hybrid (P. reticulatum × Pseudoplatystoma corruscans), both reared in net cages. The experiment was carried out for 216 days in net cages that were placed in a 24-ha dam, in a completely randomized experimental design with two treatments (cachara and the cachapinta hybrid) and three replicates, totaling six experimental units (13.5-m3 net cages). The average weights of the fish at the start of the experiment were 75.00 ± 0.004 g (cachara) and 85.00 ± 0.001 g (hybrid). An exponential model was chosen to analyze the growth curve of the morphometric traits in each genetic group. The likelihood ratio test was used to compare the growth curves, where the equality of the A (initial size) and (K growth rate) parameters was checked. There was no difference between the growth curves (similar A and K parameters) between cachara and the cachapinta hybrid for weight, standard length, body height, body width, or head length. For head length, the A parameter (1.7416 cm) was lower (P < .05) and the K parameter (0.00499 cm) was higher (P < .05) in cachara than in the hybrid (A: 1.9445 cm; K: 0.00441 cm/day). For body length, only the A parameter (6.4970 cm) was higher (P < .05) in the cachara (A: 6.0033 cm). In conclusion, the growth curve of the cachapinta hybrid is similar to that of cachara for weight and most of the morphometric traits, demonstrating that the hybrid does not have superior growth characteristics in this low density net setting.

14 show abstract
0044-8486 * * 29696269
Publication date: Available online 12 March 2019

Source: Aquaculture
Author(s): J.G. Herranz-Jusdado, V. Gallego, C. Rozenfeld, M. Morini, L. Pérez, J.F. Asturiano

Maturation in captivity of European eel (Anguilla anguilla) requires long and costly hormonal treatments that often lead to asynchronic maturation between sexes. Therefore, optimization of sperm short-term storage methods and cryopreservation protocols can be a key factor for successful artificial fertilization. Two experiments were carried out to optimize the existing protocols.
For the short-term storage experiment, sperm was diluted in P1 extender and then stored at different dilution ratios (1,9 and 1,49). The best outcome was then tested at different temperatures (4 and 20 °C) and in constant agitation or still. In the cryopreservation experiments, large sperm volumes (cryotubes of 2 and 5 ml), different cooling rates (freezing tubes 1 or 3 cm above liquid nitrogen during 15 and 20 min), and different extender compositions (methanol 10% was used as cryoprotectant, and complemented with FBS 20%, BSA 5% or egg yolk 5%) were tested. Sperm kinetic parameters were analyzed with a CASA-Mot system both in fresh and short- or long-term stored samples.
In the short-term storage trial, sperm quality did not show significant differences in the first 24 h after sperm collection between the different storage conditions tested. For longer time, 1:49 dilution ratio showed significantly better results than 1:9, and low temperature (4 °C) was better for sperm preservation after 3 days.
Cryopreserved sperm samples showed good motility results when they were frozen in cryotubes of 2 and 5 ml, with no significant differences compared to samples cryopreserved in lower volumes (straws of 0.5 mL). Furthermore, the combination of methanol (10%) and egg yolk (5%) as freezing medium, induced significant higher post-thawing motility values (over 50%) than the control (methanol 10%), whereas the addition of FBS (20%) and BSA (5%) led to a significant reduction of the sperm motility. The establishment of these storage and cryopreservation protocols will be important for the improvement of European eel artificial reproduction programs.

15 show abstract
0044-8486 * * 29696271
Publication date: Available online 11 March 2019

Source: Aquaculture
Author(s): Pengwei Xun, Heizhao Lin, Ruixuan Wang, Zhong Huang, Chuanpeng Zhou, Wei Yu, Qianqian Huang, Lianjie Tan, Yun Wang, Jun Wang

The study was conducted to investigate the effects of dietary vitamin B1 on growth performance, intestinal digestion and absorption, intestinal microflora, and the immune response of juvenile golden pompano. Six isonitrogenous and isolipidic diets were formulated, containing diet-1 (0 mg/kg), diet-2 (4.88 mg/kg), diet-3 (8.15 mg/kg), diet-4 (12.00 mg/kg), diet-5 (17.40 mg/kg) and diet-6 (20.40 mg/kg) of vitamin B1. The diets were fed to juvenile golden pompano (initial body weight:11.20 ± 0.15 g) for 8 weeks. The study indicated that dietary vitamin B1 significantly increased weight gain rate (WGR) (P < .05), specific growth rate (SGR) (P < .05), and feed efficiency ratio (FER) (P < .05) of golden pompano. Dietary vitamin B1 levels had a significant effect on serum total cholesterol (TC) (P < .05), glucose (GLU) (P < .05), C4 complement (C4) (P < .05) and lysozyme (LZM) (P < .05). A diet supplemented with 12.00 mg/kg vitamin B1 increased the activities of hepatic total antioxidant capacity catalase (CAT) (P < .05), superoxide dismutase (SOD) (P < .05), glutathione peroxidase (GPX) (P < .05), glutathione reductase (GR) (P < .05), transketolase (TK) (P < .05) and hepatic vitamin B1 accumulation (P < .05), decreasing the activities of hepatic malondialdehyde (MDA) (P < .05). A diet supplemented with 12.00 mg/kg vitamin B1 improved intestinal digestion and absorption by increasing the activities of intestinal chymotrypsin (P < .05), γ-glutamyl transferase (γ-GT) (P < .05), and creatine kinase (CK) (P < .05). Dietary vitamin B1 also increased the intestinal microvilli length and microvilli numbers to a certain degree. Dietary vitamin B1 increased the richness and the diversity of the microbial community (P < .05; Tukey test). Dietary vitamin B1 increased the number of Pseudomonas and restricted the number of Mycoplasma and E. shigella in intestine. A quadratic regression analysis on weight gain and hepatic vitamin B1 concentrations indicated that the optimum dietary vitamin B1 levels for the optimal growth of juvenile pompano were 12.94 and 12.61 mg/kg, respectively.

16 show abstract
0044-8486 * * 29696272
Publication date: Available online 11 March 2019

Source: Aquaculture
Author(s): Luís F. Baião, Filipa Rocha, Mónica Costa, Tiago Sá, Ana Oliveira, Margarida R.G. Maia, António J.M. Fonseca, Manuela Pintado, Luisa M.P. Valente

Paracentrotus lividus gonads are considered a prized seafood delicacy due to its organoleptic features. The increasing market demand for sea urchin depleted several wild stocks, thus aquaculture can play an important role in supplying high-quality animals. Nevertheless, the success of this activity largely depends on the development of nutritionally balanced diets capable of producing excellent gonads. In this study, four extruded diets formulated with low or high protein (30 and 50% dry matter (DM), LP and HP, respectively) and lipid (6 and 11% DM, LL and HL, respectively) levels were fed to wild-caught individuals (4.5 cm diameter) for 15 weeks. Twelve homogeneous groups of 15 individuals were randomly distributed by mesh cages (45 urchins/m2) within 250 L tanks in a recirculating aquaculture system (RAS) at 18 °C and a 12 L:12 D photoperiod regime. Sea urchins fed the LP/LL diet were compared to wild specimens with similar maturation stage.
All experimental diets were well accepted by sea urchins and resulted in similar final body weight (42–43 g). No significant differences were observed in specific growth rate or protein efficiency ratio among diets. The HP diets led to a decrease of dry matter and energy intake resulting in the lowest feed conversion ratio (FCR). Weight gain, whole body composition and nutrient gain remained similar among dietary treatments. The gonad somatic index (GSI) varied between sex but was similar among dietary treatments (19–23%) and was higher than values observed in wild specimens (6–7%). Females had significantly higher total concentration of carotenoids than males, irrespectively of the dietary treatments. Dietary treatments and sex did not affect gonad texture (firmness and resilience) or colour parameters (brightness, redness, yellowness, chroma or hue angle), but affected gonad composition. Total carotenoid content in gonads was not affected by diets and resulted in lower values compared to wild specimens. These had higher levels of echinenone, β-cryptoxantin and β-carotene and showed higher redness and firmness values when compared to the LP/LL diet, irrespectively of the sex. Gonad lipid content and n-3 PUFA were higher in female than in male, whilst protein content showed an opposite trend, suggesting some sex related differences in the metabolic use of nutrients.
This study clearly shows that it is possible to enhance sea urchin gonad yield in relation to wild animals in a RAS at 18 °C. All diets were effective in promoting gonad growth, but the diet with the lowest protein (30% DM) and lowest lipid (6% DM) level resulted in the highest gonad yield in both sexes.

17 show abstract
0044-8486 * * 29732007
Publication date: Available online 18 March 2019

Source: Aquaculture
Author(s): Isabel Fuentes-Santos, Uxío Labarta, X. Antón Álvarez-Salgado

Understanding and modelling bivalve growth dynamics under variable environmental conditions are crucial for the development of management and sustainability aquaculture plans. This work proposes a new dynamic bivalve growth model that combines net production Dynamic Energy Budget (DEB) theory and the species-specific growth dynamics of the Ecophysiological Model for Mussels (EMMY). In our approach, the assimilated energy is first used for metabolic requirements, and the surplus partitioned between shell formation, somatic growth, reserves and reproduction. We also incorporate site-specific estimates for feeding and spawning. We compare the performance of our model with a standard DEB model for the simulation of mussel growth in a low seston environment (Ría de Ares-Betanzos, NW Spain). Our model provides realistic estimations of shell and soft tissue growth, while the standard DEB model overestimates soft tissue growth. Indeed the Relative Mean Square Error (RMSE), which measures the discrepancy between field and simulated shell-soft tissue relationships, of our model is below 10% of that obtained with the standard DEB. Our model also captures the different effects of environmental variability on shell and flesh growth.

18 show abstract
0044-8486 * * 29732008
Publication date: Available online 18 March 2019

Source: Aquaculture
Author(s): M. Carvalho, D. Montero, M. Gesto, A. Lencina, I. Lund, M. Izquierdo

The replacement of fish oils in aquafeeds by vegetable oil sources is known to cause a depletion in dietary n-3 LC-PUFA, particularly in DHA and EPA. This decrease may influence several performance indicators in fish, including health status and stress resistance and response. The present study aimed to evaluate the effect of dietary n-3 LC-PUFA levels (0.8, 1.4 and 2.6%), below and above the requirement estimated for growth, in stress response of meagre juveniles exposed to an acute and prolonged stress. Fish were submitted to an acute stress by chasing for 15 s, and a prolonged stress by cage confinement for 7 days. The lowest n-3 LC-PUFA levels (0.8 and 1.4%) led to higher post-stress plasma cortisol levels than fish fed 2.6%. Besides, acute stress led to higher levels of post-stress plasma lactate, as well as a strong neuronal serotonergic activity in fish fed the lowest n-3 LC-PUFA diets, while prolonged confinement resulted in the highest relative catalase mRNA levels in fish fed 1.4% n-3 LC-PUFA. Therefore, the dietary changes in n-3 LC-PUFA, essential for marine fish, induce a change in the stress response in meagre, significantly increasing glucocorticoid and serotonergic response in fish fed low n-3 LC-PUFA contents. Furthermore, low n-3 LC-PUFA diets generates greater alterations in relation to basal levels of oxidative stress-related genes and, possibly increasing the oxidative stress damage. However, meagre denotes a good adaptation to both acute and prolonged stress, even when fed with low n-3 LC-PUFA diets, highlighting the high stress resistance of this species.

19 show abstract
0044-8486 * * 29732009
Publication date: Available online 16 March 2019

Source: Aquaculture
Author(s): Haokun Liu, Handong Li, Hui Wei, Xiaoming Zhu, Dong Han, Junyan Jin, Yunxia Yang, Shouqi Xie

High-throughput sequencing of the 16S rRNA gene of microbial communities was used to investigate how biofloc technology (BFT) improved water quality and fish yield in freshwater pond aquaculture. Three treatments included conventional treatment (CT), biofloc treatment (BT) and biofloc systems augmented with floc-forming bacterium (Zoogloea resiniphila MMB) treatment (BZT). The feeding trial lasted for 8 weeks with triplicate groups of cyprinid species in nine enclosures, which were placed in an outdoor pond to simulate a real aquaculture environment. Biofloc was generated by adding organic carbon and continuous aeration, which resulted in reducing dissolved nitrogen from 22% to 14% and sedimentary nitrogen from 49% to 5% and increasing nitrogen accumulation in biofloc and fish biomass. Nitrogen content in fish biomass increased from 28% in a CT to 42% when BFT was applied. Changes in the bacterial community and stimulation of biofloc formation played a central part in transferring nitrogen from remaining food, excreta and feces to bacteria and fish biomass. Z. resiniphila MMB did not outcompete indigenous communities and had no impact on floc formation by direct addition to the pond. Filamentous bacteria comprised the major structure of biofloc, while the proportion of zoogloea-forming microorganisms was very low. The proportion of aerobic heterotrophic microorganisms increased in both BFT treatments. Actinobacteria promoted the formation of floc and could have secondary benefits of protecting against fish pathogens, such as Aeromonas sp., though may increase the accumulation of off-flavor in the water and fish tissue.

Graphical abstract

20 show abstract
0044-8486 * * 29732010
Publication date: Available online 16 March 2019

Source: Aquaculture
Author(s): Chang Xu, Xiaodan Wang, Fenglu Han, Changle Qi, Erchao Li, Jianlin Guo, Jian G. Qin, Liqiao Chen

The α-lipoic acid (α-LA) is a novel feed additive to improve growth, antioxidant capacity and lipid metabolism in animal husbandry. In this study, isonitrogenous and isoenergetic diets were formulated at seven levels of α-LA (0, 300, 600, 1200, 2400, 4800, or 9600 mg/kg) and fed to the Chinese mitten crab Eriocheir sinensis juveniles for eight weeks. According to weight gain and specific grwoth rate, the optimal level of α-LA supplement in the diet is estimated at 1339–1574 mg/kg for E. sinensis. The α-LA supplement significantly increased the activities of SOD, GSH-Px and T-AOC, and the content of GSH in the hepatopancreas except for SOD in the crabs fed 9600 mg/kg α-LA. Excess dietary α-LA supplement increased the content of MDA in the hepatopancreas. The E. sinensis fed 2400 mg/kg α-LA in the diet showed the highest mRNA expressions of es_TGL1, es_TGL2, es_IL and es_DGL and had higher lipid catabolism when taking 300 mg/kg α-LA than other diets, which coincides with higher mRNA expressions of es_IL, es_DGL and CPT-1 in the hepatopancreas. The crab fed 2400 mg/kg α-LA significantly modified 45 metabolites in serum compared with the control. The supplmentation of α-LA significantly influenced fatty acid metabolism, amino acid metabolism, carnitine metabolism and accumulation of plant antioxidants. This study indicates that α-LA is a promising feed additive to regulate growth, antioxidant status and lipid metabolism in E. sinensis, but its inclusion in the diet should be <2400 mg/kg α-LA to maximize the benefitial effect and minimize side effects.

21 show abstract
0044-8486 * * 29772533
Publication date: Available online 22 March 2019

Source: Aquaculture
Author(s): Beata Irena Cejko, Daniel Żarski, Katarzyna Palińska-Żarska, Mariola Słowińska, Radosław Kajetan Kowalski

The quality of fish sperm is characterized by relatively high individual variation. Moreover, under artificial conditions, the collected sperm loses its motility and viability very rapidly, which may decrease fertilisation success. Therefore, techniques able to secure and maintain a high biological value of collected fish sperm are needed in hatchery practice. Herein, we used previously composed artificial seminal plasma (ASP) containing 2 mM CaCl2, 1 mM Mg2SO4, 20 mM Tris, 110 mM NaCl and 40 mM KCl (pH 7.5 and 310 mOsm kg−1) to dilute common carp sperm samples for 1 h storage prior to fertilisation. Sperm was collected from mature males and, after checking its motility (MOT) using the CASA system, was divided into high (range 55–65%) and low (range 5–10%) quality. Samples of both sperm qualities (high/low) were diluted tenfold (1: 9; sperm: extender) in ASP and stored for 24 h at 10 °C. Motility (MOT, PRG) and velocity (VCL, VSL) of low- and high-quality sperm diluted in ASP increased after 1 h of storage compared to undiluted sperm. Moreover, the fertilisation capacity of low-quality sperm (previously diluted and stored for 1 h in ASP) increased three times compared to undiluted sperm of the same quality. Prolonging the time of sperm storage in ASP to 24 h results in the further increase of MOT, PRG and VCL in the low quality samples and PRG in the high quality samples. The results of the presented study confirm the possibility of common carp sperm revitalisation using ASP. The utilisation of such sperm in hatchery practice is possible since the fertilisation capacity of sperm, previously diluted and stored for 1 h in ASP, was over 90% regardless of the initial sperm quality (high/low).

22 show abstract
0044-8486 * * 29772534
Publication date: Available online 22 March 2019

Source: Aquaculture
Author(s): Seyyed Morteza Hoseini, Morteza Yousefi, Seyed Hossein Hoseinifar, Hien Van Doan

Ammonia toxicity is common and risk factor in aquaculture, deteriorating fish health. Phytochemicals might attenuate adverse effects of ammonia toxicity in fish. The present study aimed to investigate the effects of dietary myrcene and menthol administration on common carp (Cyprinus carpio) health in response to ammonia toxicity. The fish were fed with either myrcene- or menthol-supplemented diets for 30 days before exposure to 0.5 mg/L unionized ammonia for 24 h. The experimental diets contained 0, 0.1, 0.25, 0.5 and 1% of either myrcene or menthol. Growth performance was determined after the 30-d feeding trial and the fish were blood-sampled before and after the ammonia challenge. The results showed that myrcene at 0.5% significantly improved the fish growth performance compared to the control diet (29.3 vs. 41.2% weight gain); however, menthol had no significant effects on the fish growth performance. Ammonia exposure led to significant decrease in plasma catalase, glutathione peroxidase, blood RBC and hemoglobin and significant increase in plasma superoxide dismutase, malondialdehyde, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase, which are indicators of oxidative stress, tissue damage and anemia. Myrcene at 0.25–1% and menthol at 0.25% levels significantly improved most of the tested parameters. Moreover, myrcene at 0.5 and 1% significantly inhibited the adverse effects of ammonia exposure on the fish antioxidant responses, tissue health and anemia; however, menthol was less effective compared to myrcene and the most effective concentration was 0.25%, which mitigated the adverse effects of ammonia exposure. In conclusion, myrcene at 0.5% and menthol at 0.25% levels are effective in reducing the adverse effects of ammonia toxicity in common carp. Such effects seem to be related to the compounds antioxidant effects, which mitigated ammonia-induced tissue damage and anemia.

23 show abstract
0044-8486 * * 29772535
Publication date: Available online 22 March 2019

Source: Aquaculture
Author(s): Arkadiusz Nędzarek, Przemysław Czerniejewski, Agnieszka Tórz

Chinese mitten crab (Eriocheir sinensis) is a valued foodstuff in China. However, their elemental composition is still poorly understood. Therefore, the aim of this study was to quantify the concentrations of Al, As, Ca, Cd, Cu, Fe, K, Mg, Na, Ni, Pb, Se, and Zn in muscle, hepatopancreas, gonads, gills, and exoskeletons of E. sinensis caught in spring and autumn in the Szczecin Lagoon, and to compare these levels to Dietary Reference Intake. High levels of Ca (>20, 000 μg g−1) in the exoskeleton, K (5,980 μg g−1) and Zn (80.8 μg g−1) in muscle, Ni (0.678 μg g−1) and Cd (0.3278 μg g−1) in the hepatopancreas, As (0.0411 μg g−1) and Se (0.3208 μg g−1) in the gonads, Fe (204 μg g−1), Cu (59.0 mg g−1), and Pb (0.0742 mg g−1) in the gills were measured. The edible parts of E. sinensis caught in Poland can be a valuable source of macro- and microelements important in human diet. Levels of Pb and Cd did not exceed the established food safety level of 0.50 μg g−1. The results showed that introduction of commercial fishing of this species may be profitable and would also comply with the European Union's legal regulations concerning the reduction of invasive animal populations in Europe.

24 show abstract
0044-8486 * * 29772536
Publication date: Available online 21 March 2019

Source: Aquaculture
Author(s): H.R. Knutsen, I.H. Johnsen, S. Keizer, M. Sørensen, J.A.C. Roques, I. Hedén, K. Sundell, Ø. Hagen

Spotted wolffish (Anarhichas minor) is a promising candidate for diversification of cold-water aquaculture. An increased knowledgebase is needed concerning the capacity of spotted wolffish to utilize a variety of feed ingredients such as microalgae and terrestrial plants. The aim of the study was therefore to investigate the effect of incorporating graded levels of microalgae (Nannochloropsis oceanica) on fish welfare indicators (growth, hepasomatic index, hematological parameters), fast muscle cellularity, chemical and fatty acid composition. Three isonitrogenous and isocaloric diets were formulated; one control diet (0% N. oceanica) and two diets with low (7.5% N. oceanica) and high (15% N. oceanica) levels of microalgae replacing fishmeal and wheat in the diets. After 12 weeks of feeding, the fish showed low growth compared to previous wolffish studies (0.26% SGR). However, this effect was not treatment dependent as there were no differences in growth or fast muscle cellularity among the three treatment groups and hematological parameters showed no indications of stress in the fish fed microalgae. Hepatosomatic index decreased over the course of the experiment for all treatment groups; a significantly larger reduction was noted in the algae-fed fish compared to the control. The omega-3 fatty acid EPA increased in the whole body of the fish fed diets containing microalgae. The results suggest that spotted wolffish has potential to utilize inclusions of up to 15% of the microalgae N. oceanica.

25 show abstract
0044-8486 * * 29772537
Publication date: Available online 21 March 2019

Source: Aquaculture
Author(s): Elena Coccia, Roberta Imperatore, Graziella Orso, Dominique Melck, Ettore Varricchio, Maria Grazia Volpe, Marina Paolucci

In this study, we utilized a model of trout intestinal explants to investigate the uptake and the metabolic effects of Hydroxytyrosol (HT), a bioactive molecule belonging to polyphenols, present in the fruit and leaf of the olive (Olea europaea L.). Fragments of the pyloric caeca (PC), mid intestine (MI) and distal intestine (DI) of the rainbow trout Oncorhynchus mykiss, were incubated with varying concentrations (2.0–20–200 μM) of HT for 5, 15, 60, 120 and 360 min. HT was uptaken by PC and MI, but not DI. The HT concentration reached the highest value after 15 min of incubation. 2.0 and 20 μM HT were well tolerated by both PC and MI, 200 μM HT was cytotoxic, causing DNA damage in PC, but not in MI. 1H NMR analysis of PC and MI incubated with 2.0 and 20 μM HT revealed the increase in the essential amino acids and fatty acids, suggesting that HT slowed down the amino acid degradation while acting as lipolysis stimulators. The effect of HT on the intestinal macromolecular asset was also investigated by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) in order to test the advantages of this method in the analysis of biological samples. HT caused macromolecular modifications coherent with the results of the HT uptake, cytotoxicity and 1H NMR analysis.
In conclusions, the intestinal explants allow many experimental conditions to be tested simultaneously. Such ex vivo approach may be usefully employed to study the effects of additives or feed components in screening tests before designing in vivo trials. Thus, it may represent an alternative to reduce the number of animals employed. Finally, the present study confirms the validity of ATR-FTIR as a rapid, non-invasive, high-resolution analytical method of analysis for biological samples.

26 show abstract
0044-8486 * * 29772538
Publication date: Available online 21 March 2019

Source: Aquaculture
Author(s): Koji Murashita, Hiroyuki Matsunari, Haruhisa Fukada, Nobuhiro Suzuki, Hirofumi Furuita, Hiromi Oku, Ivar Rønnestad, Hazuki Yoshinaga, Takeshi Yamamoto

To characterize the effects of a plant-based low-fishmeal (LFM) diet on the digestive physiology of yellowtail, Seriola quinqueradiata, we prepared two isonitrogenous and isolipidic diets; an FM-based diet (diet Control, FM 50%) and a plant protein (soybean meal and corn gluten meal)-based low fishmeal diet (diet LFM, FM 15%), and examined the acute and chronic effects of the diets on the digestive physiology of the fish were examined. In the acute effect trial (fed only a single meal), the fish fed the LFM diet displayed faster gastric emptying, lower pH of the gastrointestinal content and suppressed pancreatic digestive enzymes (trypsin, chymotrypsin and amylase) secretions. In the chronic effect trial (feeding for six weeks), in addition to the effects observed in the acute trial, the fish fed the LFM diet also displayed suppressed stomach pepsin secretion and pancreatic digestive enzymes production (gene expression). Furthermore, gene expression levels of digestion-regulating hormones, gastrin, cholecystokinin and peptide yy were also disrupted by the long-term administration of the LFM diet. Taken together, these results indicate that a plant protein-based low fish meal diet appears to not fully activate or stimulate the digestive system of yellowtail in either the short or long term and that its inhibitory/disruptive effects become more pronounced on a long-term basis. The effects we have identified on yellowtail digestive physiology could serve as important indicators to improve the plant-based low-fishmeal diets.

27 show abstract
0044-8486 * * 29772539
Publication date: Available online 20 March 2019

Source: Aquaculture
Author(s): Ricardo Shohei Hattori, Túlio Teruo Yoshinaga, Naoto Katayama, Shoko Hattori-Ihara, Ricardo Yasuichi Tsukamoto, Neuza Sumico Takahashi, Yara Aiko Tabata

Surrogate broodstock technology is emerging as a promising biotechnology for xenogeneic production of gametes of highly valuable fish species. In this study, we produced gametes of landlocked Atlantic salmon using triploid rainbow trout as recipient through germ cell transplantation technique in embryos. Spermatogonial cells were obtained from Atlantic salmon juveniles and transplantation conducted into the coelomic cavity of 150 mixed-sex triploid embryos of rainbow trout. Colonization efficiency assessed in larvae four weeks post-transplantation showed presence of PKH-26-labeled cells in 61.1% of individuals. Analysis in sexually mature adults revealed presence of donor-derived sperm in four transplanted males (10%), whereby one of them reached sexual maturity in the first year. Transplanted females became mature after the second year and donor-derived oocytes were detected in four individuals (12.1%). Milt produced by transplanted triploid males were used for artificial insemination. Genetic analysis of hatchlings revealed that progeny was composed by pure Atlantic salmon and therefore were donor-derived. In conclusion, this study shows that surrogate broodstock can be used to produce oocytes and spermatozoa using species from different genus. The production of surrogate gametes using species with a shorter life cycle represents an efficient approach to streamline the development of improved strains in aquaculture industry.

28 show abstract
0044-8486 * * 29772540
Publication date: Available online 20 March 2019

Source: Aquaculture
Author(s): Wang Hui, Shi Wenjing, Wang Long, Zhu Chuankun, Pan Zhengjun, Chang Guoliang, Wu Nan, Ding Huaiyu

Photoperiod and light intensity have been shown to play important roles in the growth of larval fish. In terms of the effect of light conditions on the larval growth of Nile tilapia, previous studies are confined to examining the effect of only photoperiod rather than of their combined effects. The face-centered composite experimental design and response surface methodology were utilized to investigate the combined influences of photoperiod and light intensity on the feed conversion and larval growth of Nile tilapia in this study. Based on the results of pilot experiments, photoperiod ranged from 8 h to 24 h, light intensity from 100 lx to 2000 lx (1.26–25.20 μmol m−2 s−1). Results showed that under indoor recirculating rearing system varying growth rhythms occurred with different light conditions; interaction between the two factors was detected, and the light intensity was more important in impacting on growth than photoperiod in the larval stage, implying that light intensity and photoperiod ought to be examined in concert rather than separately. If light intensities are held invariable, the photoperiod studies would lead to the choice of>18 h photoperiod for the best larval growth. Response surface of the larval growth was roughly consistent with that of feed conversion, indicating that the larval growth was realized through feed conversion. Relationship of the larval growth and feed conversion to artificial light conditions could be reliably quantified in a second-order form, through optimization of which optimal two-factor combination, 14–16 h/1650–1900 lx (20.79–23.94 μmol m−2 s−1), was derived with the reliability as high as ca. 98%. There is therefore the potential for maximizing larval growth in hatcheries via manipulation of artificial light regimes. According to our findings, continuous lighting should not be recommended for optimal growth in larviculture. These findings underscore the important role of light conditions during the larval stage of Nile tilapia and should be taken into consideration for the optimization of rearing protocols in Nile tilapia hatcheries.

29 show abstract
0044-8486 * * 29772541
Publication date: Available online 19 March 2019

Source: Aquaculture
Author(s): Leyciane Tayana de Souza Silva, Ulisses de Pádua Pereira, Hugo Mendes de Oliveira, Elenice Martins Brasil, Scheila Anelise Pereira, Edsandra Campos Chagas, Gabriel Fernandes Alves Jesus, Lucas Cardoso, José Luis Pedreira Mouriño, Maurício Laterça Martins

Essential oils are obtained from vegetal material and present antibacterial activities, antioxidant, antiviral, antifungal properties and may replace the use of chemotherapeutics for treating and prophylaxis in fish farm. The objective of this study was to verify the influence of essential oil of Mentha piperita in the prevention of Streptococcus in Nile tilapia. A total of 300 fish with approximately 5 g were divided into 20 tanks with 15 fish each were fed diet supplemented with essential oil at concentrations of Mentha 0.075%; Mentha 0.125%; Mentha 0.25% and two controls (commercial feed and feed+cereal alcohol) in quadruplicate, during 50 days. At the end of the supplementation period, four fish from each experimental unit were collected for hemato-immunological analysis and the rest of the animals were challenged against Streptococcus agalactiae intraperitoneally. During seven days after infection, the fish were monitored every three hours for mortality registration. Zootechnical performance indexes were measured based in the biometries each 15 days along the experimente and did not present significant difference as well as the hematological parameters. Total plasmatic protein was higher in fish fed Mentha 0.125% than those fed Mentha 0.25%. After the challenge, unlike the animals whose diet did not contain essential oil, the animals that received supplemented ration maintained their alimentary activity. The supplementation with the essential oil increased the resistance of the fish after the challenge with S. agalactiae and survival was significantly higher in fish fed with Mentha 0.25%.

30 show abstract
0044-8486 * * 29772542
Publication date: Available online 19 March 2019

Source: Aquaculture
Author(s): Wenfang Dai, Qiongfen Qiu, Jiong Chen, Jinbo Xiong

Increasing evidence has revealed a tight association between host diseases and dysbiosis in its gut bacterial communities. However, it remains uncertain whether this interplay also holds true for gut eukaryotes. To fill this knowledge gap, using Illumina sequencing the eukaryotic 18S rRNA genes, we explored the gut eukaryotic signatures of Pacific white shrimp (Litopenaeus vannamei) suffered from white feces syndrome (WFS). The gut eukaryotic communities in WFS shrimp differed significantly (P < .001) from healthy cohorts, accompanied with a significant (P = .016) reduction in diversity. Compared with healthy shrimp, Basidiomycota and Ascomycota were overrepresented, while Desmodesmus and Gymnodiniphycidae were underrepresented in WFS ones. A phylogenetic-based mean nearest taxon distance (MNTD) analysis revealed that WFS significantly (P = .008) shifted ecological processes that govern the gut eukaryotic community from determinism to stochasticity. In addition, WFS shrimp exhibited less connected and cooperative interspecies interactions as compared with healthy cohorts. Notably, we identified 14 disease-discriminatory taxa that were indicative of shrimp health statuses, with an overall 96.4% diagnosis accuracy. In addition, the 14 taxa between pre-WFS and corresponding healthy shrimp exhibited the same change direction (increased or decreased) with that of WFS, suggesting that the identified disease-discriminatory taxa are not transient and predictive of WFS onset. Among these, 11 indicators were affiliated with Opisthokonta and Archaeplastida phyla, which conjointly contributed 39.8% dissimilarity of the gut microbiotas between healthy and WFS shrimp, indicating that WFS occurrence could be attributed to dysbiosis of the two phyla. Collectively, our findings provide an integrated overview on the intimate association between WFS and gut eukaryotes. In addition, the gut disease-discriminatory taxa can serve as indicator for quantitatively diagnosing the incidence of shrimp WFS.

31 show abstract
0044-8486 * * 29772543
Publication date: Available online 19 March 2019

Source: Aquaculture
Author(s): M.A. Ruiz, C.M. Hernández-Cruz, M.J. Caballero, H. Fernández-Palacios, R. Saleh, M.S. Izquierdo, M.B. Betancor

Systemic granulomatosis has already been reported in meagre larvae with an adequate feeding protocol and enrichment media preventing its appearance in the first weeks of life. Afterwards, the control of this disease could be prevented through nutritional components of the inert food, being the antioxidants the key to success. For this reason, in the present study, meagre larvae were reared from 30 days post hatching (dph) with five isonitrogenous and isolipidic experimental microdiets with different levels of vitamin E and C: C– (40 mg kg−1 E, 100 mg kg−1C), C+ (400 mg kg−1 E, 1000 mg kg−1C), Krill (400 mg kg−1 E, 1000 mg kg−1C and substitution of fish oil by krill oil), EC (200 mg kg−1 E, 500 mg kg−1C) and EECC (800 mg kg−1 E, 2000 mg kg−1C). Prior to this, larvae were co-fed with rotifers and Artemia following a protocol which prevented the appearance of granulomas, as previously demonstrated. The substitution of fish oil by krill oil significantly increased levels of eicosapentaenoic acid (EPA, 16.6%) and docosahexaenoic acid (DHA, 17.6%) in meagre, consequently increasing the peroxidation index, which in turn translated into a higher incidence of granulomas. Although even low levels of vitamin E and C (40 mg kg−1 E, 100 mg kg−1C; C-) allowed the adequate growth of larvae, these levels were not enough to prevent the appearance of granulomas, requiring superior levels of both antioxidant vitamins (800 mg kg−1 E and 2000 mg kg−1C) to mitigate systemic granulomatosis. This mitigation was simultaneous with the reduction of thiobarbituric acid reactive substances TBARs content in larvae, which were highly correlated with the appearance of granulomas (R2 = 0.892, y = 0.0446× + 0.0756). A strong negative correlation was observed between the dietary levels of vitamin E (y = −0.0098× + 11.174, R2 = 0.8766, p value = .019, r = −0.93) and vitamin C (y = −0.0022× + 6.4777, R2 = 0.9278, p value = .003, r = −0.96) and the percentage of larvae with granulomas. The results showed that the occurrence of systemic granulomatosis seems to be associated to the larvae peroxidation status, so that high dietary levels of vitamin E and C (800 and 2000 mg kg−1, respectively; Diet EECC), reduced lipid peroxidation and completely prevented the appearance of granulomas in meagre larvae at 44 dph.

32 show abstract
0044-8486 * * 29873093
Publication date: Available online 23 March 2019

Source: Aquaculture
Author(s): Mengyu Zhang, Luqing Pan, Fei Huang, Shuo Gao, Chen Su, Mingzhu Zhang, Ziyan He

With the increasing production of farmed Litopenaeus vannamei, the discharge of culture sewage and the accumulation of deleterious substances (nitrite, ammonia, sulfide…) in ponds have been more severe, especially at the mid-late farming stage, severely inhibiting the sustainability of aquaculture. Considering vital roles of microorganisms in cycling processes, we thereupon comprehensively investigated microbiotas in water, sediment and effluent of L. vannamei ponds under different culture modes by 16S rRNA gene and metagenome sequencing. Results revealed that microbial communities in water, sediment and effluent of white shrimp ponds were diverse and had active metabolism. Genes related to quorum sensing were abundant. Furthermore, we uncovered carbon fixation, such as CBB, WL and 3-HP; N, S, P cycling except nitrification and sulfide oxidation were active in shrimp farming environments at mid-late farming stage. Remarkably, each gene encoding key enzyme involved in cycling processes were assigned to specific taxa, such as Rhodobacteraceae, Rubrivivax and so on. Interestingly, many functional taxa (Vibrio, Aeromonas) were also potential pathogens to shrimp and microbiotas' structure along with function were correlated with environmental factors, reminding us of regulating variations of environmental factors during the shrimp farming period. Meanwhile, water, sediment and effluent under different culture modes had different microbial diversity and characteristics. Notably, we called for urgent management of direct discharge of aquaculture sewage including numerous genes related to human diseases, which is vital to public health. Briefly, this was the first study analyzing microbiotas' structure, function, ecology cycling in different L. vannamei culture surroundings and their correlation with environmental factors, advancing our knowledge for aquaculture ecosystems and providing preliminary data for probiotics screening and cycling regulation in the future.

33 show abstract
0044-8486 * * 29873094
Publication date: Available online 22 March 2019

Source: Aquaculture
Author(s): Yao-Wu Fu, Cheng-Ke Zhu, Qi-Zhong Zhang

Largemouth bronze gudgeon (Coreius guichenoti) is a fish endemic to the middle and upstream reaches of the Yangtze River in China. Indoor culture and domestication of C. guichenoti have yet to see success in part because of Ichthyophthirius multifiliis infection, which causes 100% mortality in these fish. Here, we investigated whether the complement components C3 and C9 in C. guichenoti play a role in immune reactions against I. mulifiliis. Full-length C3 and C9 cDNA sequences were determined and analyzed. The C3 cDNA sequence comprised 5142 bp encoding 1643 amino acids. The C9 cDNA sequence comprised 2206 bp with an open reading frame of 2085 bp. The mRNA expression of C3 and C9 genes was detected in the liver, spleen, and trunk kidney, and as well as that of C3 gene in head kidney. I. multifiliis infection significantly upregulated mRNA expression of C3 and C9 in liver and spleen. However, no transcript was detected in the skin of C. guichenoti post-infection with I. multifiliis, and might be responsible for C. guichenoti to be vulnerable to the parasite. The results suggest that C3 and C9 are involved in defense against the ectoparasite I. multifiliis, and promote understanding function of the complement components C3 and C9 in C. guichenoti.

34 show abstract
0044-8486 * * 29873095
Publication date: Available online 22 March 2019

Source: Aquaculture
Author(s): Adriane Erbice Bianchini, Quelen Iane Garlet, Patrícia Rodrigues, Carine de Freitas Souza, Lenise de Lima Silva, Alessandro Casale dos Santos, Berta Maria Heinzmann, Bernardo Baldisserotto

S-(+)-linalool is a phytochemical with proven sedative and anesthetic effects in silver catfish (Rhamdia quelen); however, the pharmacokinetic profile of this compound in fish remains unknown. Therefore, this study describes the pharmacokinetics of S-(+)-linalool in silver catfish anesthetized by immersion bath. Fish were exposed to 153 mg/L S-(+)-linalool for a maximum of 30 min. Blood and brain samples were collected at several time-points up to 4.0 h (0.5 h of anesthesia and 3.5 h of recovery) after the onset of exposure. Before each tissue/blood sampling, the anesthesia stage of each animal was recorded. Following S-(+)-linalool quantification in plasma and brain tissue by gas chromatography with flame ionization, concentration curves were constructed for determination of the pharmacokinetic parameters. S-(+)-linalool in the plasma and brain was detected within the first 2 min (0.03 h) of exposure, with maximum times (Tmax) of 0.50 and 0.33 h and maximum concentrations (Cmax) of 129.33 μg/mL and 113.92 μg/g, respectively. Other parameters estimated for the plasma and brain were terminal half-lives (T1/2β) of 1.36 and 57.27 h, elimination constants (Kel) of 0.50 and 0.01/h, areas under the curve from zero to 4.0 h (AUC0–t) of 120.98 μg/mL/h and 250.57 μg/g/h, and AUCs from zero to infinity (ASC0–∞) of 132.15 μg/mL/h and 4946.13 μg/g/h, respectively. After 10 min (equivalent to a collection time of 0.66 h) in a drug-free bath, all animals recovered from anesthesia. These results suggest that S-(+)-linalool is promptly absorbed into the bloodstream and widely distributed to the brain. Elimination is efficient in plasma but slower in the brain, yet this factor does not impair the recovery of animals, which occurs quickly. Therefore, S-(+)-linalool holds a pharmacokinetic profile suitable for its application as an anesthetic in aquaculture.

35 show abstract
0044-8486 * * 29944659
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Alton F. Burns, Delbert M. Gatlin

Creatine is a multifunctional organic acid necessary for various physiological processes and is commonly supplemented to improve muscle growth and performance of humans. However, the effects of supplemented creatine in the diets of fishes is unclear. Thus, two feeding trials were conducted to examine the performance of juvenile red drum fed diets supplemented with creatine. The first feeding trial was conducted for 7 weeks, to determine the optimal dietary supplementation of creatine for red drum at low (5 ppt) salinity. Red drum is a euryhaline species and potential benefits of creatine may include enhanced energy utilization during osmoregulation. Therefore, the second trial was a two-part, 12-week, feeding trial. During the first 7 weeks, salinity was maintained at 3 ppt (low salinity), then, for an additional 5 weeks, maintained at 15 ppt (moderate salinity). The basal diet for both feeding trials was formulated to contain 40% crude protein, contributed equally by menhaden fishmeal and soy protein concentrate, and 10% lipid. For trial 1, five experimental diets were derived from the basal diet by supplementing creatine at 0.5, 1, 1.5, 2, or 4% by weight at the expense of cellulose. The diets for trial 1 were adjusted with a 50/50 blend of aspartate and glutamate to maintain the diets isonitrogenous. For trial 2, the same basal diet and one supplemented with creatine at 2% were prepared with the creatine-supplemented diet adjusted with a 50/50 blend of aspartate and glutamate on an equal-weight basis. In trial 1, significant (P ≤ .05) positive trends were observed in weight gain, feed efficiency, and survivability of fish fed the diets supplemented with creatine. Broken-line regression analysis indicated creatine supplementation at 1.98% of diet provided optimal weight gain of red drum. In trial 2, there was a trending increase in percent weight gain and feed efficiency of fish fed the creatine supplemented diet during the moderate salinity portion of the trial, resulting in significant improvements over the 12-week period. Results from these study confirm that red drum benefit from dietary creatine supplementation in practical diets.

36 show abstract
0044-8486 * * 29944660
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Bruno L. Gianasi, Jean-François Hamel, Annie Mercier

The environmental control of reproductive processes is central to both fundamental and applied aspects of animal ecology. The present study experimentally assessed how environmental factors modulate gametogenesis and spawning and impact embryo development and survival in the holothuroid Cucumaria frondosa, a cold-water echinoderm with lecithotrophic development. Adults were exposed to three seawater temperatures, four photoperiod regimes, and two food concentrations during 120 days overlapping the natural gametogenic and spawning periods. Among all the treatments tested, exposure to ambient conditions of water temperature (−1 to 3 °C), photoperiod (8 to 13 h of light) and food concentration (3 × 103 ± 896 rotifers g−1 of sea cucumbers d−1) yielded the greatest reproductive output and embryo survival. At pre-spawning, males and females had the highest gonad index (~33%) and where filled with mature gametes. At spawning, females in ambient conditions released the highest number of oocytes (1.2 × 103 oocytes female−1) and yielded the highest embryo survival rates (21% at 20 days post fertilization). Individuals exposed to warmer water temperatures (6 and 12 °C) experienced delayed gametogenesis and did not spawn. Individuals under 24-h light, 24-h dark, and advanced (4 months) photoperiods showed delayed gametogenesis and low numbers of oocytes released; moreover, embryos died within 10 days post fertilization. Individuals fed with high food concentration (6 × 103 ± 982 rotifers g−1 of sea cucumbers d−1) showed similar results to ambient conditions, suggesting that increased food supply neither decreased nor enhanced reproductive output over the experimental period. This study sheds new light on the environmental drivers of reproductive success in C. frondosa, which is of value for developing conservation strategies and mariculture protocols in cold-water holothuroids with lecithotrophic development.

37 show abstract
0044-8486 * * 29978825
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Zoltán Bokor, Gergely Bernáth, Levente Várkonyi, József Molnár, Zete Levente Láng, Zsófia Tarnai-Király, Enikő Solymosi, Béla Urbányi

In the presented study, effects of sperm cryopreservation methods (Polystyrene box-P. box vs a controlled-rate freezer-CRF) and various semen confection methods during freezing (5 mL straw vs. 10 mL cryotube) on sperm motility parameters and fertilization capacity of wels catfish (Silurus glanis) were tested. In general, pMOT (Control: 89 ± 3%, Straw P. box: 50 ± 9%, Straw CRF: 53 ± 12%, Cryotube: 52 ± 7%) and BCF (Control: 30 ± 1 Hz, Straw P. box: 27 ± 1 Hz, Straw CRF: 26 ± 1 Hz, Cryotube: 27 ± 1 Hz) showed significant reduction following thawing. ALH reduced significantly in the case of the straw frozen with P. box (1.2 ± 0.2 μm) compared to the fresh control (1.5 ± 0.1 μm). However, VCL (Control: 108 ± 6 μm/s, Straw P. box: 107 ± 5 μm/s, Straw CRF: 108 ± 8 μm/s, Cryotube: 109 ± 7 μm/s) and VSL (Control: 94 ± 6 μm/s, Straw P. box: 99 ± 4 μm/s, Straw CRF: 99 ± 9 μm/s, Cryotube: 99 ± 7 μm/s) did not decrease. A significantly higher LIN was measured using the straw cryopreserved in the P. box (92 ± 2%) and the CRF (91 ± 2%) in comparison with the fresh control (86 ± 1%). No significant difference in the fertilization capacity when eggs were fertilized by frozen/thawed (Straw P. box: 75 ± 5%, Straw CRF: 72 ± 3%, Cryotube: 66 ± 6%) or fresh (control, 68 ± 4%) semen was observed (P > .05). As well, no significant correlation between none of sperm motility parameters tested and the fertilization rate were recorded (P > .05). All tested sperm cryopreservation showed a similar high efficiency in the hatchery practice of wels catfis.

38 show abstract
0044-8486 * * 29978826
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Yijia Deng, Mei Qiu, Yaling Wang, Rundong Wang, Pengli Lu, Lijun Sun, Xuepeng Li, Ravi Gooneratne

Mycotoxin contamination of plant-based food adversely affects growth and health of tilapia (Oreochromis niloticus) and a search is underway for naturally occurring biological agents that can protect against these mycotoxins. Therefore, diets containing the antioxidants quercetin, rutin and tea polyphenols were investigated for their effects on T-2-toxin-induced growth behavior, antioxidant response, histopathological changes and T-2 residues in tilapia. Five groups of tilapia were exposed to increasing doses of T-2, supplemented with antioxidants (control, T-2, T-2 + quercetin, T-2 + rutin, T-2 + tea polyphenols) for 20 d to evaluate the protective effects of antioxidants on growth, antioxidant enzyme activity, histopathology, and residues in fish liver and muscle. The results indicated that exposure to increasing T-2 doses significantly decreased the survival rate, weight gain and hepatosomatic index, induced liver cell and myofiber damage, and increased T-2 residues in liver and muscle. Dietary supplementation with antioxidants effectively reduced the damage to fish liver and muscle. Tea polyphenols significantly enhanced liver glutathione-S-transferase activity. In conclusion, quercetin, rutin and tea polyphenols significantly reduced liver and muscle damage in tilapia. Supplementation of tilapia diet with rutin was most beneficial with improved growth, increased liver antioxidant capacity, and markedly reduced liver and myofiber damage. Thus, addition of antioxidants to fish diets could potentially be used to resist mycotoxin-related morbidity and mortality in fish.

39 show abstract
0044-8486 * * 29978827
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Tania Pérez, Claudio Alba, Marina Aparicio, Javier de Andrés, José A. Ruiz Santa Quiteria, Juan M. Rodríguez, Alicia Gibello

The gut microbiota plays a key role in animal health, including immune and metabolic homeostasis. Despite the economic relevance of the sturgeon, studies addressing the gut microbiome of this species are scarce and have focused only on the hindgut. The objective of this work was to use Illumina metabarcoding technology to compare the bacterial microbiomes of two different intestinal locations, the proximal intestine (small intestine) and the distal intestine (hindgut containing the spiral valve), of healthy Siberian sturgeons (Acipenser baerii) reared on two different farms in Spain. Although a high degree of interindividual variability was observed, certain differences between the anatomical parts and between the geographical locations were clear. The results show that the sequences corresponding to the most abundant taxa were the basis for clustering according to anatomical region (proximal and distal intestine), whereas the less abundant taxa were the basis for clustering according to the geographical location of the fish farms. Finally, the results also indicate the existence of certain bacteria that are present in the intestinal tracts of all the fish analyzed in this study; this information may be useful in future studies aiming to establish differences based upon fish health or disease.

40 show abstract
0044-8486 * * 30015545
Publication date: 30 May 2019

Source: Aquaculture, Volume 507
Author(s): V. Gnanavel, Selvaraj Mohana Roopan, S. Rajeshkumar

Marine organisms inhabit almost around two-third of the total earth surfaces. The abundance of wide range of marine organisms makes the systematic classification of a marine organism and systematic research on marine compounds hard-hitting. Natural compounds obtained from marine organisms are used in the treatment of various diseases and disorders since ancient times. Most of the marine compounds obtained from the marine organisms are pharmacologically bioactive and they are significantly effective against various types of diseases. In the present review, the different types of seaweeds like carotenoids, polyunsaturated fatty acids, phycocolloids and sterols are discussed along with their chemical ecology. The present review will also help the researchers from various disciplines like marine and phytochemistry to understand the chemical ecology of seaweeds. This review also emphasises on the importance of various marine bioactive metabolites which are responsible for diverse pharmacological activities of different classes of seaweeds and helps in the identification lead molecules for the discovery of new drug molecule from marine sources.

Graphical abstract

41 show abstract
0044-8486 * * 30015546
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Walker D. Wright-Moore, Wade O. Watanabe, Andrea J. Bourdelais, M.S. Alam, Troy C. Rezek, Patrick M. Carroll, Christopher A. Woolridge

Spawning performance and egg quality were compared in wild-caught and F1 generation southern flounder broodstock following induction with mammalian mLHRHa or piscine sGnRHa at different doses. Forty F1 and 33 wild vitellogenic females (mean oocyte diameter ≥ 0.385 mm) were implanted with an 80% cholesterol-20% cellulose pellet at doses (μg/kg bw) of 0 (control), 5 (low), 25 (mid) and 50 (high) mLHRHa, or with similar doses of sGnRHa. Ovulated females (N = 5–8 per treatment) were strip-spawned and eggs were fertilized in vitro with sperm from two males. Egg quality was categorized according to fertilization and hatching success: 75–100% (high), 50–75% (medium-high), 25–50% (medium-low), and 0–25% (low). Egg production (number of eggs/kg female bw × 103) was highest at the low dose of mLHRHa in F1 females (146.4) and sGnRHa in wild females (128) and was lowest at the intermediate dose sGnRHa in F1 females (61.9) and the high dose sGnRHa in wild females (40.6). Number of fertilized eggs produced per kg bw (× 103) was highest at the low dose mLHRHa in F1 females (113.5) and sGnRHa in wild females (95.4) and lowest at the high dose sGnRHa in F1 females (18.7) and sGnRHa in wild females (7.8). Number of yolksac larvae produced per kg bw (× 103) was highest at the low dose of mLHRHa in F1 females (74) and sGnRHa in wild females (73.5) and was lowest at the high dose of sGnRHa in F1 females (2.0) and in wild females (1.2). Number of larvae per kg bw (× 103) surviving to 96 h post-hatching was highest at the low dose mLHRHa in F1 females (67.5) and sGnRHa in wild females (66.5) and was lowest at the high dose sGnRHa in F1 (0.72) and sGnRHa in wild females (0.68). In F1 females, larval production was significantly greater (P < .01) at lower doses and greater (P < .01) for mLHRHa than for sGnRHa at all doses. For wild females, larval production was greater at lower doses of sGnRHa, with the inverse trend observed for mLHRHa (hormone dose × type interaction, P < .05). Taurine concentrations (nmol/mg dw) were higher (P < .05) in ovulated eggs of high quality (27.4) than in eggs of med-low (14.8) and low (17.5) quality, supporting an important role in broodstock nutrition and in early development. The results help standardize GnRHa therapies for spawning of wild and F1 southern flounder.

42 show abstract
0044-8486 * * 30015547
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Tomoki Honryo, Tokihiko Okada, Michio Kurata, Yasunori Ishibashi, Yasuo Agawa, Yoshifumi Sawada

We conducted a chemical analysis of the blood of juvenile Pacific bluefin tuna (PBF; Thunnus orientalis) showing abnormal swimming (AS) behavior, such as irregular and/or frantic patterns, and compared them to normally-swimming (NS) fish in order to elucidate causes of death in aquaculture-reared tuna. This study found three abnormal characteristics in the blood chemistries of AS specimens; 1) hyperventilation accompanied by significantly higher PO2 and lower PCO2 than NS, 2) metabolic alkalosis owing to excessive excretion of protons, and 3) hyperkalemia. Hence, PBF juveniles are subject to mortality due to respiratory failure and homeostatic imbalances in acid-base regulation, even in the absence of physical injury. This indicates that since PBF juveniles are ram ventilators, even light collision impacts can be fatal for PBF juveniles if swimming activities are affected.

43 show abstract
0044-8486 * * 30015548
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Matheus D. Baldissera, Carine F. Souza, Sharine N. Descovi, Camila M. Verdi, Carla C. Zeppenfeld, Aleksandro S. da Silva, Roberto C.V. Santos, Bernardo Baldisserotto

Grape pomace is a by-product of the winemaking process, rich in bioactive compounds such as resveratrol and has antioxidant and antimicrobial properties. Recent evidence has demonstrated the protective effects of grape against impairment of the phosphoryl transfer network, a system linked to energetic homeostasis of high-energy phosphoryl transfer, to maintain energetic balance. Also, Pseudomonas aeruginosa infection in fish has been related to severe impairment of the branchial phosphoryl transfer network via inhibition of creatine kinase (CK), adenylate kinase (AK) and pyruvate kinase (PK) activities. Thus, the aim of this study was to evaluate whether dietary supplementation with grape pomace flour (GPF) is able to reduce or prevent the impairment of cellular energetic homeostasis in grass carp (Ctenopharyngodon idella) experimentally infected by P. aeruginosa. Branchial CK (cytosolic and mitochondrial), AK, and PK activities were lower in infected animals on day 15 post-infection (PI) compared to uninfected fish, while lactate dehydrogenase (LDH) activity was higher. Branchial reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), lipid oxidation (LOOH) and protein carbonylation levels were higher, while the level of non-proteic (NPSH) and proteic (PSH) thiols was lower in infected fish on day 15 PI, as compared to uninfected fish. The use of 300 mg of GPF/kg of feed was able to ameliorate the activities of CK, AK, PK, and LDH as compared to infected fish, but their activities remained different from the control group. On the other hand, dietary supplementation with 300 mg of GPF/kg of feed was able to prevent all alterations linked to oxidative damage elicited by disease. Based on this evidence, inhibition of the phosphoryl transfer network may contribute to the impairment of intracellular energetic communication between cellular ATP synthesis and consumption and is mediated by oxidative damage in the gills of fish infected by P. aeruginosa. The use of 300 mg of GPF/kg of feed exerted protective effects on branchial energetic metabolism linked to ATP metabolism by reducing the impairment in cellular energetic homeostasis; its effects can be mediated by the prevention of SH group oxidation.

44 show abstract
0044-8486 * * 30015549
Publication date: 15 May 2019

Source: Aquaculture, Volume 506
Author(s): Megan N. Dethier, Katie Dobkowski, Alifaire Noreen, Malise Yun, Abigail Moosmiller

Predation, especially by crabs, is a common source of mortality for natural and farmed populations of intertidal clams. Consumption of juvenile “seed clams” forces aquaculturists to try to exclude predators and/or raise juveniles in hatcheries until they can reach a size refuge. We ran a variety of lab experiments assessing vulnerabilities of juvenile clams to small, common shore crabs (Hemigrapsus spp.). Crabs <1 cm width can consume hardshell Manila clams larger than those normally used for “seed”, and can readily crush even larger softshell Mya clams. We suggest that using netting to prevent consumption by shore crabs is not practical given that smaller individuals can fit through mesh openings. Raising seed in hatcheries until they are 10–15 mm will provide a size refuge from shore crabs, but not larger cancrid crabs. Farming on beaches with little habitat (e.g., cobbles) for shore crabs can likely reduce juvenile clam mortality. A better understanding of predation threats to commercially important clams is critical, especially as the invasion of the green crab Carcinus to Washington shorelines further threatens survival of juvenile clams.

45 show abstract
0044-8486 * * 30015550
Publication date: Available online 6 April 2019

Source: Aquaculture
Author(s): Celia Agusti-Ridaura, Lars A. Hamre, Per G. Espedal, Øivind Øines, Tor E. Horsberg, Kiranpreet Kaur

Caligus elongatus is a generalist sea louse infesting a wide range of wild and farmed fish in the North Atlantic. Like its relatives Lepeophtheirus salmonis and Caligus rogercresseyi, C. elongatus is a well known pathogen in farmed salmonids, and it also infests farmed cod. The mitochondrial gene cytochrome C oxidase I (mtCOI) is used as a marker for C. elongatus identification at the species and subspecies level, with two genotypes (possibly sibling species) being identified thus far. Sea lice can cause problems in farmed fish when abundant. Salmon farms use chemical, non-chemical and preventive treatments for controlling lice numbers. It is highly plausible that C. elongatus could develop resistance to chemical delousing treatments, similar to its related species, L. salmonis and C. rogercresseyi, which have developed reduced sensitivity against several anti-louse chemicals. In the current study, we aimed to provide data on C. elongatus sensitivity status towards four major anti-louse chemicals (azamethiphos, deltamethrin, emamectin benzoate and hydrogen peroxide). We collected a number of lice from wild saithe and farmed Atlantic salmon from three localities in the West coast of Norway. Lice were kept in lab culture and six-dose bioassays were carried out on the louse offspring for the four anti-louse chemicals. In addition, we screened the samples for the two mitochondrial genotypes using a TaqMan probe assay. The results showed that most of the C. elongatus specimens were sensitive to all the delousing chemicals tested. Lice from one of the farms had lower immobilization rate at the highest H2O2 concentration than lice from wild fish, which might be due to sensitivity loss. The mtCOI genotyping revealed the presence of only one genotype (genotype 1) in our sample set. The current study provides, for the first time, the baseline sensitivity levels of C. elongatus to four major anti-lice chemicals used on salmon farms. This would provide a good reference point for future studies or monitoring programs to keep a regular check on the sensitivity levels of this parasite.

46 show abstract
0044-8486 * * 30015551
Publication date: Available online 5 April 2019

Source: Aquaculture
Author(s): Theerawut Phusantisampan, Puntanat Tattiyapong, Palita Mutrakulcharoen, Malinee Sriariyanun, Win Surachetpong

Tilapia lake virus (TiLV) is a newly emerging viral disease in tilapia with recent outbreaks in many parts of the world. There is an urgent need to develop an accurate, sensitive, on-farm method for rapid detection of TiLV to limit economic loss and prevent the spread of the virus into new geographical areas. In this study, we developed a rapid, one-step reverse transcription, loop-mediated, isothermal amplification (RT-LAMP) method for the detection of TiLV in fish tissues. Our results revealed that the RT-LAMP assay was able to detect TiLV infection in infected cell culture materials, and fish samples collected from different geographic locations in Thailand. In total, 166 tissue samples were collected from TiLV-infected fish and uninfected fish from tilapia farms in Thailand with a history of TiLV outbreaks, and fish showing clinical signs of TiLV infection were tested using our RT-LAMP protocol. The RT-LAMP assay offered high specificity and sensitivity compared to reverse transcription polymerase chain reaction (RT-qPCR) assay. These results supported the application of the RT-LAMP assay for the diagnosis of TiLV with benefits including reduced analysis time and easy interpretation of results based on the colorimetric change, thus offering a diagnostic tool in resource-limited countries where there is an urgent need for rapid diagnostic assay to guide TiLV control.

47 show abstract
0044-8486 * * 30015552
Publication date: Available online 5 April 2019

Source: Aquaculture
Author(s): S. Allred, W. Shao, M.W. Schilling, L. Petrie-Hanson, P.J. Allen

Nonstandard Channel Ictalurus punctatus and Hybrid I. punctatus × I. furcatus Catfish fillets are rejected by catfish processors primarily due to aberrations in muscle texture or coloration (i.e., yellow, pink, red), and represent an economic loss for both the processer and farmer. Of these fillet types, red fillet is characterized by red coloration, with affected areas ranging from a solitary spot to the whole fillet. The present study investigates the prevalence of red fillet within the catfish industry and evaluates compositional differences in fillets by means of color, proximate composition, and microbial presence between red (diffuse red patch), punctured (singular red spot), and acceptable fillets. Red fillets with presence of different bacteria were also compared histologically. In order to evaluate the occurrence of red fillet, subsamples of acceptable and rejected fillets were obtained biweekly from a commercial processing plant over the course of a year, with rejected fillets sorted as red, punctured, or neither. Red fillets accounted for an average of 0.13% fillets from each pond harvest, representing an estimated annual loss of $443,000 for catfish farmers and $683,000 for catfish processors. Red and punctured fillets did not significantly differ in color (lightness and redness), pH, fat, protein, or moisture. Red and punctured fillets were darker, redder, and yellower than acceptable fillets. Acceptable fillets had more fat and less moisture than red and punctured fillets. Microbial analyses were similar for both red and punctured fillets with Aeromonas sobria being the most prevalent bacterium (62%) followed by Plesiomonas shigelloides (28%) and A. hydrophila (19%). Fewer acceptable fillets had bacteria than red or punctured fillets, with A. sobria as the most abundant bacterium (24%). The prevalence of A. sobria in red catfish fillets may warrant further investigation into the effect of bacteria on the development of red fillets in intensively-reared Channel and Hybrid Catfish.

48 show abstract
0044-8486 * * 30015554
Publication date: Available online 4 April 2019

Source: Aquaculture
Author(s): Tipsuda Thongbuakaew, Saowaros Suwansa-ard, Prapee Sretarugsa, Prasert Sobhon, Scott F. Cummins

The giant freshwater prawn, Macrobrachium rosenbergii, is an important aquaculture species in many Asian-Pacific countries due to its high economic value. A better understanding of hormones that regulate reproductive processes, including development and maturation of gametes, will facilitate more efficient breeding and larval production in prawn aquaculture. In this study, we identified four gene transcripts from the M. rosenbergii that encode crustacean female sex hormones (CFSHs), which were designated as MroCFSH1a, MroCFSH1b, MroCFSH2a and MroCFSH2b, based on primary sequence and phylogeny. We also show that CFSH may have evolved from an ancestral protein similar to the interleukin 17. All MroCFSH genes are present in the central nervous system (CNS) as well as in other tissues, including the ovaries and testes. The expression level of all MroCFSH during ovarian development is significantly higher in the CNS compared to the ovary. In the brain, MroCFSH expression is localized to small-sized neurons of neuronal clusters 9, 10, and 11, and in the medium- and large-sized neurons of neuronal clusters 14 and 15; regions known to regulate feeding and reproductive behaviors. In the ovary, MroCFSHs expression are found in the oogonia, previtellogenic and early vitellogenic oocytes. A role for CFSHs in M. rosenbergii reproduction was supported following experimental administration of serotonin to ovarian explant cultures, showing an upregulation of MroCFSHs.

49 show abstract
0044-8486 * * 30015555
Publication date: Available online 4 April 2019

Source: Aquaculture
Author(s): Ishfaq Nazir Mir, Irfan Ahmad Bhat, Showkat Ahmad Dar, K.K. Jain, Tincy Varghese, Rakhi Kumari, A.P. Muralidhar, P.P. Srivastava

To understand the carbohydrate utilization ability during developmental stages of Clarias magur, the mRNA levels and enzyme activity of amylase were studied. Furthermore, the transcript levels of some important growth genes like growth hormone (GH), insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein (IGFBP) were evaluated. The enzymatic activity and mRNA expression of alpha-amylase along with expression of growth-related genes were examined from hatching until 34 days post-hatching (dph) by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Subsequently, mRNA expression pattern revealed the significantly (P < .05) high transcript level of alpha-amylase during early stages and early peaks were found at 3 to 6 dph, later the expression decreased till the end of experiment. Growth-related genes like GH, IGF-I and IGFBP showed a variable level of mRNA expression pattern from 0 dph to 34 dph. However, there was no significant difference (P > .05) in the mRNA expression of growth-related genes among the different time points of the present study. Moreover, the amylase activity revealed almost same pattern as that of its mRNA expression. In general, the present results suggested that C. magur has the ability to utilize the digestible carbohydrates during the early stages and can be helpful in developing low cost feeds for larvae.

50 show abstract
0044-8486 * * 30015556
Publication date: Available online 4 April 2019

Source: Aquaculture
Author(s): Marcela Cristina Flexa do Amaral, Natalia Bianca Caires Medeiros, Marília Danyelle Nunes Rodrigues, Marcos Rodrigues, Leandro de Lima Sousa, Elson Cardoso de Jesus, Igor Guerreiro Hamoy

Consumer exigencies demands that fish farmers use technological advances to increase the product standards and quality, involving better management and productivity levels. Aiming to investigate the technological practices of fish farming in the Amazon region, in this study, we performed an explanatory factor analysis (EFA) of data from a survey conducted with fish farmers in the southeast region of Pará state. The EFA model grouped the technological variables in four factors. We then normalized factors scores for each subject in each factor to construct an index of technological practices adoption (ITA) to determine the most used or the most neglected technology in terms of adoption by fish farmers. In addition, we performed a linear regression to identify the most influential variables that interfered with technological adoption. The Southeast Amazon region has a great potential to expand fish farming, however most fish farmers have adopted few technologies that are aimed at improving production. The results of ITA demonstrate that most fish farmers in Amazon do not use the recommended technological practices for the activity, as 85% percent of them were classified as low or very low in terms of technology adoption. Small-scale farmers are more likely to adopt management practices than large farmers. In large properties, fish farming is understood as a secondary activity, with cattle ranching being the predominant economic activity, in contrast, small-scale farmers invest more in technology because fish farming is their primary activity. For a long-term development strategy, both small and large farmers need greater technology adoption, thus establishing innovation networks and developing continuous mechanisms of resilience, which are still absent in the current sector.

51 show abstract
0044-8486 * * 30015557
Publication date: Available online 3 April 2019

Source: Aquaculture
Author(s): Rahul Krishnan, Jong-Oh Kim, Jae-Ok Kim, Syed Shariq Nazir Qadiri, Soo-Jin Kim, Myung-Joo Oh

Here, we report the characterization of four calcium-independent cell adhesion molecules, viz- nectin-1, 2, 3 and 4 from seven-band grouper Hyporthodus septemfasciatus a high valued marine finfish susceptible for nervous necrosis virus (NNV) infection. Structural analysis of the nectin molecules revealed an N-terminal V domain, two constant C2 domains, a transmembrane domain, and a cytoplasmic tail. All the nectin molecules except nectin-4 shared a C-terminal interaction motif (E/AxYV). Phylogenetic analysis revealed a close relationship between seven-band grouper nectins and zebrafish nectins. Also, nectins ubiquitously expressed in all the tissues of healthy fish with higher transcript abundance in the brain, gill and anterior kidney. Significant up-regulation of nectin-4 expression was observed in the brain of NNV challenged fish followed by the gill and kidney. Further, docking simulations of nectins with NNV capsid proteins revealed a strong interaction with nectin-1 and nectin-4. Our findings suggest that nectins might have a possible role to play in NNV neuropathogenesis. The present observations provide potential clues for further elucidating the involvement of nectins in NNV pathogenesis and could help in the development of new antiviral therapeutics inhibiting the NNV entry to the cell.

52 show abstract
0044-8486 * * 30015558
Publication date: Available online 3 April 2019

Source: Aquaculture
Author(s): Martin Perez-Velazquez, Delbert M. Gatlin, Mayra L. González-Félix, Armando García-Ortega, Clement R. de Cruz, María L. Juárez-Gómez, Kequan Chen

A 6-week growth trial was conducted to assess the replacement of fishmeal (FM), soy protein concentrate (SPC) and fish oil (FO) by Arthrospira sp. and Schizochytrium limacinum meals in diets for hybrid striped bass (Morone chrysops × M. saxatilis) juveniles of 10.6 ± 0.2 g initial individual weight (±standard deviation). A control diet was formulated with equivalent contributions of FM and SPC to provide 40% crude protein. Menhaden FO was the main lipid source, providing 10% crude fat. Five experimental diets replaced 10, 20, 30, 40 and 50% of FM, SPC, and FO from the control diet by combining two algal meals derived from the freshwater autotroph Arthrospira sp. and the marine heterotroph S. limacinum. Each diet was randomly assigned to three replicate aquaria, and twelve group-weighed fish were stocked per aquarium. Fish were group-weighed weekly to adjust the feeding ration, which started at 6% and gradually decreased to 3%, confirmed by visual feeding cues to avoid overfeeding. At the end of the trial, no statistical differences for responses such as condition factor (P = .6778), hepatosomatic index (P = .4542), intraperitoneal fat ratio (P = .0997), or feed efficiency (P = .2210) were detected. However, statistically significant differences were observed for percent weight gain (WG; P = .0323) and thermal growth coefficient (TGC; P = .0164). Weight gain (209.5%) and TGC (0.088) of fish fed the control diet was significantly lower than fish fed the 30 and 50% replacement diets (WG: 232.8–235.3%), but no differences were detected among fish fed any of the other replacement levels (WG: 217.1–227.9%). Whole-body proximate composition showed no statistical differences among fish for crude protein, moisture, or ash, except for crude fat content (P < .0001); the highest percentage of fat (9.3%) was observed in fish fed the 30% replacement level. The dietary fatty acid profile influenced the fatty acid profile of fish, eliciting an increment in the content of specific fatty acids, such as 16:0, 18:2n-6 and 22:6n-3. Although higher docosahexaenoic acid (DHA) content was observed in whole-body of hybrid striped bass fed the experimental diets, this fatty acid did not contribute to a higher body lipid content. The findings indicate that the combination of Arthrospira sp. and S. limacinum meals can replace a significant proportion of fish-derived feedstuffs in hybrid striped bass feeds, promoting suitable growth performances with up to 50% replacement under these conditions, and promoting the accumulation of DHA in fish tissues, which would ultimately benefit consumers.

53 show abstract
0044-8486 * * 30015559
Publication date: Available online 3 April 2019

Source: Aquaculture
Author(s): Hongqiang Xu, Qi Li, Ziqiang Han, Shikai Liu, Hong Yu, Lingfeng Kong

Crassostrea nippnoa is a potential aquaculture species because of its unique flavor, delicious taste and edibility during the summer, while C. gigas is a major global aquaculture species due to the fast growth rate, high disease resistance and strong environmental adaptability. This study firstly described the reciprocal hybridization between the two oyster species, and four crosses were produced: C. gigas ♀ × C. gigas ♂ (GG), C. gigas ♀ × C. nippona ♂ (GN), C. nippona ♀ × C. gigas ♂ (NG) and C. nippona ♀ × C. nippona ♂ (NN). The embryonic development of reciprocal crosses was similar to that of the pure crosses. However, fertilization rates were obviously different between the reciprocal hybrids and parental species, where the fertilization rates of reciprocal hybrids were significantly lower than those of parental species. At larval stages, the survival rates of the hybrid cohorts were significantly lower than those of inbred cohorts, and the critical stage of reciprocal hybrids where highest mortality occurred was the umbo period. The growth rate of GN progeny was not different from the inbred cohorts, while the growth rate of the NG progeny was higher than that of inbred cohorts. Furthermore, both hybrid cohorts had normal metamorphosis and produced viable spats. During the spat stage, the survival rates of reciprocal hybrids were not different from that of GG spat but were much higher than that of the NN spat. The growth rates of reciprocal hybrids were comparable to that of GG spat but significantly higher than that of NN spat. The shell height of the reciprocal crosses GN and NG were increased by 46.66% and 60.75% compared with the NN cross at day 360, respectively. The reciprocal hybrids had significant survival advantage and growth heterosis compared to NN cohort. The results demonstrated that the cross NG was deemed to be the better hybridization combination for genetic improvement, which could have a potential utilization for oyster aquaculture.

54 show abstract
0044-8486 * * 30015560
Publication date: Available online 3 April 2019

Source: Aquaculture
Author(s): Laura González, Richard S. Taylor, Andrew R. Bridle, Philip B.B. Crosbie, Barbara F. Nowak

Reiterative freshwater bathing is the main treatment to control amoebic gill disease (AGD) of farmed Atlantic salmon in Tasmania, Australia. Regular freshwater exposure appears to control ectoparasitic cymothoid isopods, which were only seen at high prevalence and intensity in summer when fish had not been treated for over 100 days. With the potential advent of non-freshwater AGD treatments or increased periods between freshwater bathing due to selective breeding for AGD resistance, it is possible that cymothoid parasitism will become an increasing threat on Tasmanian salmon farms. In order to establish whether isopods could be vectors of Neoparamoeba perurans Young et al. 2007 (the causative agent of AGD), gill isopods were collected from salmon that had not been bathed for seven months and carried a 95% prevalence of isopods, including Ceratothoa banksii (Leach, 1818) and Nerocila orbignyi (Guérin-Méneville, 1832). PCR analyses of gill swabs indicated that 82% of salmon were positive for N. perurans while 41% of the sampled isopods were positive for N. perurans on external surfaces. When internal material was analysed, only 9% of the isopods were positive for the amoeba, but in very low concentration. Quantitative analysis showed no correlation between the concentrations of N. perurans from gill swabs and the isopods from the same individual fish. Thus, it is unlikely that these isopods act as a significant reservoir or vector for N. perurans.

55 show abstract
0044-8486 * * 30015561
Publication date: Available online 3 April 2019

Source: Aquaculture
Author(s): Waraporn Hahor, Karun Thongprajukaew, Naraid Suanyuk

The effects of dietary supplementation of various oligosaccharide types on growth performance, gut health and immune response were investigated in hybrid catfish (Pangasianodon gigas × Pangasianodon hypophthalmus). The fish (5.50 ± 0.04 g initial body weight) were fed for 10 weeks with fish meal-soybean meal-based diets containing 0.6% of xylooligosaccharide (XOS), galactooligosaccharide (GOS), fructooligosaccharide (FOS) or mannanoligosaccharide (MOS), while the control diet was not supplemented. At the end of experiment, growth performance was similar across the five dietary treatments, but some improvements in feed utilization parameters were mainly observed in fish fed with the MOS diet, followed by the diet containing FOS. The preferred treatment improved gut health, as indicated by the activities of digestive enzymes and microvillus length. Positive responses in protein synthesis capacity and protein turnover rate as well as amount of native myosin and actin were also observed, while the carcass proximate composition did not differ across the five dietary treatments. Improved immunological response and survival rate after challenge with Edwardsiella ictaluri was achieved in fish fed with the preferred oligosaccharide type. Overall, these findings indicate that a MOS supplemented diet can improve growth performance, gut health and immune response in juvenile hybrid catfish. This prebiotic could be applied by supplementation in practical diets for this hybrid fish.

56 show abstract
0044-8486 * * 30015562
Publication date: Available online 3 April 2019

Source: Aquaculture
Author(s): Pauline Wischhusen, Maroussia Parailloux, Pierre-André Geraert, Mickael Briens, Maïté Bueno, Sandra Mounicou, Brice Bouyssiere, Antony Jesu Prabhu, Sadasivam J. Kaushik, Benoit Fauconneau, Stéphanie Fontagné-Dicharry

We studied the effects of supplementing a plant-ingredient based rainbow trout broodstock diet with different forms of selenium (Se) on reproductive performance, parental Se transfer and antioxidant metabolism in their progeny before first-feeding. Three groups of rainbow trout were fed a diet either without selenium supplementation (NC, basal Se level: 0.3 ppm) or supplemented with 0.3 ppm Se either in the form of sodium selenite (SS) or as hydroxy-selenomethionine (SO, dietary Se level: 0.7 ppm) over a 6-month period prior to spawning. In Se-supplemented groups, the total number of females spawning was significantly higher compared to the negative control group and the females fed SO began to spawn earlier compared to females fed SS or NC. Total Se concentrations were significantly higher in female muscle of SO group. Higher Se concentrations in the oocytes of both Se-supplemented groups confirmed a maternal transfer of Se, while total Se concentrations in milt samples were not significantly different between dietary groups. There was no effect on glutathione peroxidase (GPX) or other antioxidant enzyme activity in the liver of female or male broodstock, whereas in the swim-up fry, GPX activity was significantly higher in both Se-supplemented treatments with the highest activity in the SO group. Se-supplementation enhanced the expression of hepatic SelPa in broodstock males and females along with MsrB1, GPx1a, GPx4a2, CAT, Gclc, Keap1 and MsrB2 in male liver. In swim-up fry, only organic Se-supplementation led to a higher gene expression for SelPa, GPX1a, GPX1b2, CAT and MsrB2. An improvement of the oxidative status in whole-body of swim-up fry could not be confirmed in this study as the GSH/GSSG was even lower in swim-up fry of Se-supplemented groups, whereas the 8-isoprostane levels were lower in the SS group and no effect on protein carbonyl levels could be detected. Organic Se-supplementation led to a significant increase in the α-tocopherol and vitamin C levels in the progeny. These results show that dietary Se in broodstock nutrition influences spawning occurrence and along with the parental transfer, several traits in the progeny are affected.

57 show abstract
0044-8486 * * 30015563
Publication date: Available online 3 April 2019

Source: Aquaculture
Author(s): Shi-Ming Wan, Xue-Mei Xiong, Tea Tomljanovic, Yu-Long Chen, Han Liu, Tomislav Treer, Ze-Xia Gao

Most of the freshwater aquaculture fish species in the world, especially cyprinid fishes, contain intermuscular bones (IBs). Different number of IBs had been indicated among different species and strains or individuals of same species, which suggested that the trait of IBs counts has the possibility of genetic improvement through selective breeding program. In this study, two groups with extreme differences for IB number were constructed to identify IB number-associated SNPs and genes in blunt snout bream (Megalobrama amblycephala), which is one of the most important aquaculture species in China. Through whole genome resequencing and bulked segregant analysis (BSA) for two groups with extreme IBs number (IB-more group with IBs number ≥130; IB-less group with IBs number ≤100), a total of 6074 high quality SNPs with Delta-Index ≥0.5 were screened out by chi-square test and index analysis. The sliding-window analysis subsequently obtained two SNP enrichment regions, which located on chromosome 06 (32 M–34 M) and chromosome 11 (12 M–16 M), respectively, containing 21 and 300 candidate SNPs. Besides, 181 candidate SNPs with Delta-Index ≥0.8 were detected and annotated within the genome-wide range beyond above two regions. Finally, 52 SNPs were used for data reliability verification. Genotyping of SNPs in IB-less individuals and IB-more individuals and correlation analysis between candidate SNPs and IB number traits indicated that five SNPs were significantly associated with the trait of IB number. The sequences or flanking sequences where SNPs located were then annotated to different genes, which maybe closely related to IB number trait. This is the first study to explore SNPs/genes related to the number of IBs in fish by BSA. The identified dataset provides an extensive resource for understanding the molecular mechanisms underlying IB counts in teleosts and also lays the foundation for the marker assisted breeding of IB number traits in M. amblycephala.

58 show abstract
0044-8486 * * 30015564
Publication date: Available online 2 April 2019

Source: Aquaculture
Author(s): A. Carbajal, F.E. Reyes-López, O. Tallo-Parra, M. Lopez-Bejar, L. Tort

Cortisol, the end product of the hypothalamus-pituitary-interrenal (HPI) axis, has been traditionally measured in blood as indicator of stress in fish, however, the degree of invasiveness inherent to blood collection is not always possible or desirable. Instead, cortisol measurement in skin mucus is far less invasive, but as blood, this method potentially provides only a brief window of information of the HPI axis activity. The newly described method of cortisol measurement from scales may serve as a long-term, integrated measure of the HPI axis activity in fish. While skin mucus and scales cortisol measurement present practical and conceptual advantages, there are still several unclear issues related to their biological relevance that need deeper study. Accordingly, we aimed to evaluate whether skin mucus and scales cortisol levels can be reliably used as stress indicators by subjecting fish to prolonged, continuous stressful conditions. The present study demonstrates that the measurement of cortisol in skin mucus reflect circulating cortisol concentrations when fish are responding to stress with an intense activation of the HPI axis. Results also revealed that cortisol content in scales strongly correlates to circulating cortisol levels in chronically stressed fish. Besides, we provide further support that scales cortisol assessment offer a retrospective measure of the past stress experience in fish. While this study provides a good basis for future research applying the methods presented, our results open the question of whether these matrices have additional sources of cortisol other than blood, and the route of incorporation or diffusion. Further knowledge about the general robustness and stability of scales cortisol in fish subjected to prolonged stress would largely help strengthen the interpretation of hormone fluctuations in this matrix.

59 show abstract
0044-8486 * * 30015565
Publication date: Available online 2 April 2019

Source: Aquaculture
Author(s): Jia-ling Guo, Yue-lang Zhou, Hang Zhao, Wen-Yan Chen, Yong-Jun Chen, Shi-Mei Lin

This study was conducted to evaluate the effect of dietary lipid levels on growth, body composition and liver oxidative stress of largemouth bass, Micropterus salmoides. Fish were fed isonitrogenous (crude protein 45%) practical diets with five lipid levels (3.3%,8.2%,13.2%,18.1% and 23.3%, respectively) for 60 days. The results showed that weight gain (WG) and protein efficiency ratio (PER) were all significantly improved by dietary lipid levels up to 18.1% and then levelled off beyond this level. Both feed intake (FI) and feed conversion ratio (FCR) showed a decreasing trend with dietary lipid increased. Body lipid content, liver lipid content, total n-3 and n-6 PUFA content in muscle, and triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) contents in plasma significantly increased with increasing dietary lipid levels. However, body protein content, and HDL-C/TC and HDL-C/LDL-C values significantly reduced. The carnitine palmitoyltransferase I (CPT-1), lipoprtein lipase (LPL), glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK) and fructose-1,6-bisphosphatase (FBPase) activities in liver increased significantly as dietary lipid levels increased, whereas both fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) activities showed the opposite trend. Moreover, higher superoxide dismutase (SOD), catalase (CAT) and oxide synthase (NOS) activities, and nitric oxide (NO) concent in liver were recorded in fish fed diets with 18.1% lipid, while the malondialdehyde (MDA) content in liver increased as dietary lipid levels increased. Results indicated that high dietary lipid level (23.3%) inhibit weight gain and induce oxidative stress, which affect the health status of largemouth bass. Based on WG, a dietary lipid level of 18.42% was optimal for growth performance of juvenile largemouth bass.

60 show abstract
0044-8486 * * 30015566
Publication date: Available online 2 April 2019

Source: Aquaculture
Author(s): Huaqun Ye, Minglei Xu, Leling Chen, Xiaohong Tan, Shu Chen, Cuiyun Zou, Zhenzhu Sun, Qingying Liu, Chaoxia Ye, Anli Wang

A 56-day feeding trial was conducted to evaluate the effects of replacing dietary fish meal (FM) with a complementary mixture of plant protein (PP) consisting of soybean meal (SBM), corn gluten meal (CGM) and cottonseed meal (CSM) on hepatic lipid metabolism and hepatocyte apoptosis in juvenile hybrid grouper, Epinephelus lanceolatus♂ × E. fuscoguttatus♀ (31.64 ± 0.82 g). A basal diet (FM60) with FM as the sole protein source was compared to diets progressively replacing 25% (FM45), 50% (FM30) and 75% (FM15) of FM protein. No significant differences were observed in growth performance and feed utilization when up to 75% of FM protein was replaced by PP sources. The hepatosomatic index (HSI) was markedly increased as dietary PP inclusion increased, but crude lipid content in the liver showed the opposite trend. Plasma cholesterol (CHO), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) of fish fed the PP containing diets were all significantly lower than the control. Liver histological analysis showed a higher levels of hepatocyte vacuolization and nuclear pycnosis occurred as dietary PP inclusion increased, but the amounts of hepatic lipid droplets showed a decreasing trend with increasing PP inclusion levels. Moreover, dietary PP inclusion down-regulated the mRNA levels of lipid metabolism-related genes including peroxisome proliferator-activated receptor alpha (PPARα), carnitine palmitoyltransferase 1 (CPT1), apolipoprotein AI (Apo-AI) and lipoprotein lipase (LPL). On the other hand, dietary PP sources also down-regulated the apoptosis-related genes including caspase-3, caspase-7, caspase-8 and p53. The present study provided new evidence for the PP sources-induced lipid metabolism in carnivorous fish, and provided new insight into the relationship between dietary PP sources and cell apoptosis.

61 show abstract
0044-8486 * * 30015567
Publication date: Available online 2 April 2019

Source: Aquaculture
Author(s): Wang Ligai, Ma Binheng, Chen Dongxing, Lou Bao, Zhan Wei, Chen Ruiyi, Tan Peng, Xu Dongdong, Liu Feng, Xie Qingping

An 8-week feeding trial was conducted to establish the optimal dietary vitamin E requirement for juvenile yellow drum (Nibea albiflora). Fish (initial weight 32.32 ± 0.26 g) were fed six diets containing graded levels of vitamin E (α-tocopherol) (0, 20, 40, 80, 160 and 320 mg kg−1). The levels of dietary vitamin E, analyzed by high-performance liquid chromatography, were 4.0, 15.4, 36.2, 69.4, 137.9 and 292.7 mg vitamin E kg−1 diet. Weight gain and specific growth rate were significantly higher in fish fed the 69.4 mg kg−1 diet than in fish fed the 4.0 mg kg−1 diet. Among all diet treatments, the feed conversion ratio was the lowest and the protein efficiency ratio was the highest in fish fed the 69.4 mg kg−1 diet. The whole-body lipid content of fish fed the 292.7 mg kg−1 diet was significantly lower than that of fish fed the 4.0 mg kg−1 diet. Liver vitamin E concentration increased with dietary vitamin E levels up to 137.9 mg kg−1 diet, and plateaued thereafter. Fish fed the 36.2 mg kg−1 diet had significantly higher serum superoxide dismutase activity than fish fed the 137.9 mg kg−1 diet. The level of serum malondialdehyde was significantly lower in fish fed the 36.2 mg kg−1 diet than in fish fed the 4.0 mg kg−1 diet; fish fed the 292.7 mg kg−1 diet had significantly higher lysozyme activity than fish fed the 4.0–69.4 mg kg−1 diets. Subsequently, a challenge test by injection of Vibrio alginolyticus showed significantly higher cumulative mortality among fish fed the 292.7 mg kg−1 diet as compared with those fed the 15.4–69.4 mg kg−1 diets. This study demonstrated that proper dietary vitamin E could enhance growth performance, antioxidant status, and ability against bacterial infection in yellow drum juveniles. A broken-line model of percent weight gain indicated the optimal vitamin E requirement for juvenile yellow drum is 68.75 mg kg−1.

62 show abstract
0044-8486 * * 30015568
Publication date: Available online 2 April 2019

Source: Aquaculture
Author(s): Jian Han, Wan Shu Hong, Qiong Wang, Ting Ting Zhang, Shi Xi Chen

The large yellow croaker (Larimichthys crocea) is one of the most valuable economic mariculture fish in China, and its yellowness in skin is considered as the most important traits that determine the market value. The fish skin colors present naturally silvery white during the daytime and golden yellow during the night-time. In the present study, we found that the xanthosomes of xanthophores aggregated during the daytime and dispersed during the night-time, while the melanosomes of melanophores always dispersed all day long in vivo. We further cloned three proopiomelanocortin (POMC) genes of the large yellow croaker. All these POMC genes were expressed in the pituitary, but only POMC-C mRNA was expressed in the skin. The results of single-cell RT-PCR showed that the POMC-C mRNA was expressed in isolated xanthophores but not in melanophores. The xanthophores, but not melanophores, were found in the ventral skin, where only one subtype of melanocortin receptor (MCR), i.e. MC5R, was expressed. MC1R, MC4R and MC5R mRNAs were detected in the dorsal skin, where there existed both the xanthophores and melanophores. The results of single-cell RT-PCR showed that only MC5R mRNA was expressed in the xanthophores, while only MC1R mRNA was detected in the melanophores. Thirty min after in vivo and in vitro treatment with melanocyte-stimulating hormone (MSH) peptides (α-MSH, Des-Ac-α-MSH, α-MSH-C and β-MSH-C), dispersion degrees of the xanthosomes and melanosomes significantly increased, even under light exposure. Interestingly, when we immediately observed the dorsal scales that have been maintained under in vitro complete dark condition without MSH peptides treatment for at least 30 min, the melanosomes aggregated as expected, but the xanthosomes dispersed. Both α-MSH and α-MSH-C exhibited similar, but stronger effects than Des-Ac-α-MSH on dispersion of both the xanthosomes and melanosomes. Although the two MSH peptides (α-MSH-C and β-MSH-C) are generated from POMC-C, the former showed stronger effect on xanthosome dispersion than the latter. Forskolin, an Adenylyl cyclase activator, dispersed pigment granules in both the xanthophores and melanophores. H 89 2HCl, a specific inhibitor of protein kinase A blocked α-MSH-induced pigment granule dispersion of xanthophores and melanophores. Taken together, our results indicated that the dispersion of melanosomes is stimulated by MSH, possibly secreted from pituitary, through endocrine pathway. The yellowness of the large yellow croaker skin was mainly due to the dispersion of xanthosomes. The dispersion of xanthosomes was regulated by MSH that is possibly released both from the pituitary through endocrine pathway and from the xanthophores through autocrine pathway.

63 show abstract
0044-8486 * * 30015569
Publication date: Available online 1 April 2019

Source: Aquaculture
Author(s): Daichi Hayashi, Chiemi Miura, Takeshi Miura

Vertebral deformities, including kyphosis, of the cultured yellowtail Seriola quinqueradiata resulted in a decrease in product value, and consequently economic loss for fish farmers. Hence, in order to resolve this problem, it is important to examine the characteristics of kyphotic vertebrae in fish. In this study, we focused on the comparison between kyphotic and non-kyphotic two-year old yellowtail. We analyzed the appearance of the caudal vertebrae by X-ray image analysis. The strength of the vertebrae, bone density and gonad development were analyzed. Moreover, the muscles were analyzed for protein, fat, moisture, and ash content. A decrease in vertebrae strength and vertebrae bone density, thinning of compact bone, and an increase in bone porosity relative to the total spongy bone area of vertebrae were observed in kyphotic fish. However, there is no difference in weights, and there is no effect on the fleshy substance component of muscles. Histological observation of gonad suggested that spermatogenesis progressed in kyphotic fish. Our study implies that a thin compact bone area and an increase in bone porosity caused low bone strength and density, and weak vertebrae in kyphotic fish.

64 show abstract
0044-8486 * * 30015570
Publication date: Available online 1 April 2019

Source: Aquaculture
Author(s): Wuxiao Zhang, Silei Xia, Jian Zhu, Linghong Miao, Mingchun Ren, Yan Lin, Xianping Ge, Shengming Sun

Ammonia is one of the major environmental pollutants in freshwater aquatic systems that affects the survival and growth of organisms. In the present study, a nine-week experiment was conducted to investigate the chronic toxicity of ammonia on survival and selected hematological parameters, antioxidant ability, and histological structure in juvenile Chinese blunt snout bream, Megalobrama amblycephala. Fish were exposed to one of five different ammonia concentrations (0, 5, 10, 15, and 20 mg L −1 total ammonia-N, pH = 7.86 ± 0.41, temperature = 28.23 ± 0.79 °C). Growth performance of fish in the high-ammonia treatment was lower than that of fish in the control group. The survival rate in the group exposed to the highest ammonia-N concentration (20 mg L−1) was significantly lower than that of the control group. The lowest level of white blood cell count (WBC), red blood cell count (RBC), hemoglobin, hematocrit, and plasma glucose and the highest level of plasma ammonia, cortisol and aspartate transaminase were observed in fish exposed to ammonia-N at 20 mg L −1 compared with the control group. The liver superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities in fish exposure to 20 mg L −1 ammonia-N group were significantly lower than those in the control group, while oxidative stress indices (levels of malondialdehyde, MDA) was significantly higher than those in the control group. Regression analysis found that growth performance, plasma parameters, hematological parameters, and antioxidant status of fish were significant linear correlated to ammonia-N concentration. Fish exposed to various concentrations of ammonia displayed histopathologic alterations in both gill and liver tissue. Furthermore, morphological examination by transmission electron microscopy revealed that gill tissues displayed vacuolation of the cytoplasm, damaged mitochondria, increased heterochromatin, and intense desquamation of pavement epithelial cells on the gill lamellae. Our findings suggest that the stress responses induced in juvenile blunt snout bream by chronic exposure to ammonia are not limited to simple growth inhibition, but are accompanied by changes in oxidative stress, plasma parameter effects, and alterations in the histology of the liver and gill. Blunt snout bream had a dose-dependent effect on ammonia-N. We preliminarily suggest that the level of plasma ammonia, MDA, CAT, AST, FER, and SGR can be used as an indicator for chronic ammonia-N toxicity, but further research and verification are needed in the future.
65 show abstract
0044-8486 * * 30015571
Publication date: Available online 1 April 2019

Source: Aquaculture
Author(s): Hyun-Ki Hong, Ludovic Donaghy, Kwang-Sik Choi

The variously colored abalone Haliotis diversicolor is widely distributed in the northwest Pacific region and commonly occurs in shallow subtidal regions of Jeju Island, off the south coast of Korea. In this study, we first characterized the morphology and immune-related activities of H. diversicolor hemocytes using flow cytometry and light microscopy. Flow cytometry revealed three types of hemocytes in the hemolymph: granulocytes, hyalinocytes, and blast-like cells. Hyalinocytes were the largest and most abundant, while granulocytes were intermediate-sized and contained many granules in the cytoplasm. Flow cytometry indicated that granulocytes were mainly involved in phagocytosis and oxidative activities, although hyalinocytes also exhibited a certain level of immune-related activities. Blast-like cells were the smallest and exhibited a lack of phagocytosis and oxidative capacities. To understand the adaptive capacity to air exposure, abalones were exposed to air or humidity over 30 h. All abalones perished within 24 h after dry-air exposure, while 20% of abalones had survived under humid conditions by the end of the experiment. After 6 h of air exposure and 12 h of humidity, total hemocyte counts and phagocytosis capacity declined dramatically, and the level of hemocyte DNA damage increased significantly (P < .05). This study suggests that sufficient oxygen supply during transportation could enhance the survival of H. diversicolor, thereby improving its market value.

66 show abstract
0044-8486 * * 30015572
Publication date: Available online 1 April 2019

Source: Aquaculture
Author(s): Kwang Il Kim, Kyoung-Mi Won, Eun Sun Lee, Miyoung Cho, Sung Hee Jung, Myoung Sug Kim

Vibriosis is one of the major bacterial diseases observed in cultured marine fish worldwide. An epidemic trait of the Vibrio derived from cage-cultured marine fish is still lacking. To identify the Vibrio and discriminate ten Vibrio species from cage-cultured marine fish, we designed specific primers targeting the RNA polymerase sigma factor (rpoD), recombination protein F (recF), transcriptional regulator (toxR) genes (known as housekeeping genes), and two multiplex PCR sets (PCR set 1 for V. anguillarum, V. gigantis, V. atlanticus, V. harveyi, and V. scophthalmi; and PCR set 2 for V. lentus, V. splendidus, Photoacterium piscicola, V. alginolyticus and P. damselae). Moreover, each multiplex PCR assay comprised internal control primers that enabled the detection of the Vibrio. Designed primers yielded specific diagnostic results to target the Vibrio and ten Vibrio species in the multiplex PCR assays. The minimal detection limits of the multiplex PCR were each 5 ng DNA μL−1, which showed ten-fold sensitivity compared to a single PCR reaction. The novel multiplex PCR assays could contribute to detecting the Vibrio and discriminate the major Vibrio species in cage-cultured marine fish, and could be used as a reliable and informative diagnostic tool in the aquaculture industry.

67 show abstract
0044-8486 * * 30015575
Publication date: Available online 28 March 2019

Source: Aquaculture
Author(s): Dorothy Ngajilo, Mohamed F. Jeebhay

Aquaculture is one of the fastest growing food-producing sectors. Little is known of the occupational exposures, risk factors and their associated adverse health outcomes among aquaculture workers, particularly from developing countries.

To gain better insight into the occupational exposures and associated occupational diseases and injuries among aquaculture workers.

MEDLINE, Google Scholar and SCOPUS literature searches were undertaken to identify relevant studies (1960–2018). Furthermore, data from official country reports, industry, labour ministries and workers' compensation boards were reviewed.

The review identified that very few studies (3%) were reported from developing countries. Most studies that were reported focussed on farming fish and crustaceans, and less so molluscs and aquatic plants. Occupational exposure characterisation studies were mainly reported for noise (43.2–77.5 dB), chemicals such as formaldehyde in hatcheries (<0.045- > 2.0 ppm) and microorganisms such as E. coli bacteria in fish ponds (7.0 × 102–5.3x106CFU/100 ml). The most common occupational diseases included musculoskeletal disorders (MSD) (prevalence: 21–63%); respiratory symptoms and asthma (4–65%); skin infections (2.2–15.7%), dermatitis (6%) and urticaria (0.7%); occupational infections such as leptospirosis (incidence: 33/100,000PYS); and decompression illness in divers (incidence: 0.57–26.19/10,000PYS). Among crawfish farmers, tractor use was associated with increased risk of wrist pain (OR = 2.89) and lower-backache (OR = 2.41), while increased employment duration was associated with upper-backache (OR = 3.07). In fish farming, skin ailments were strongly associated with female gender (OR = 2.48); previous history of skin problems (OR = 8.50); waste-water exposure (OR = 2.74); fish farming-related jobs (OR = 3.47); lack of personal skin protective measures against wastewater (OR = 2.24) and work in the wet season (OR = 2.80). The most common injuries included falls (10–49/10,000 PYS), blows from an object (14–37/10,000 PYS), entanglement (29/10,000 PYS), pricks/cuts/punctures (29/10,000 PYS), high voltage exposures (8/10,000 PYS) and needlestick injuries (5 self-injections per 1,000,000 vaccinations). Seaweed farmers reported injuries mainly from hazardous aquatic animals and sharp shells on the seabed (54%). Preventive approaches based on the hierarchy of control measures to reduce health risks associated with hazardous exposures is existent mainly in predominantly well-resourced high income countries.

Aquaculture workers are at increased risk of developing occupational diseases and injuries attributed to various occupational hazards, and that these risks are under-reported, especially from developing countries. Future studies should explore the interaction between these environmental exposures and work organization factors in causing occupational diseases and injuries. A better understanding of key occupational risk factors and the evaluation of interventions to reduce these risks is crucial in protecting and promoting the health of workers in this sector.

68 show abstract
0044-8486 * * 30015576
Publication date: Available online 28 March 2019

Source: Aquaculture
Author(s): Stephanie M. Grodeska, Jessica L. Jones, William C. Walton, Covadonga R. Arias

Off-bottom cultivation of oysters, Crassostrea virginica, is increasing in the Gulf of Mexico. The warm ambient air and water temperatures found in the Gulf of Mexico, coupled with the target market for off-bottom cultivated oysters for live raw consumption, raise concerns about the potential infections by human health pathogens, Vibrio parahaemolyticus and V. vulnificus. Regular practices associated with off-bottom cultivation, such as desiccation, expose oysters to ambient air to eliminate bio-fouling and are also known to increase these Vibrio spp. levels in oysters. Along with cultivation methods being introduced in the Gulf of Mexico, the use of triploid oysters is becoming increasingly popular. Triploid oysters are used a majority of the time in off-bottom cultivation due to their sterility, which results in rapid growth and high summer meat quality. Research also suggests that the lack of gonad tissue may correlate with lower Vibrio spp. levels in oysters. In this study, triploid and diploid oysters were cultured in Australian long line systems and subjected to two typical desiccation practices, air dried and freshwater dipped/air dried, and then evaluated for V. parahaemolyticus and V. vulnificus abundances over time. Three two-week long studies determined that Vibrio spp. levels in oysters that underwent either desiccation treatment returned to levels similar to those of submersed oysters by day three, referred to as returning to background levels. However, the Vibrio spp. levels in the treated oysters remained not significantly different from the elevated levels seen immediately following the desiccation treatment until seven days after re-submersion. There was no significant difference in Vibrio spp. levels between triploid and diploid oysters, nor a difference in the time of re-submersion needed to return levels to background. These results suggest that oysters that have been desiccated should be re-submersed for at least seven days prior to harvest to mitigate any human health risk contributed by desiccation practices, regardless of oyster ploidy.

69 show abstract
0044-8486 * * 30015577
Publication date: Available online 27 March 2019

Source: Aquaculture
Author(s): Christian Díaz, Catterina Sobenes, Seiji Machino

Choosing an alternative species of mussel for the aquaculture industries, will be possible if it has equal or greater yield than the mussel cultivated. This study compares the growth of the chilean native mussel Mytilus chilensis with the non-native Mediterranean mussel Mytilus galloprovincialis and evaluate if environmental variables and cultivation depth affects mussels growth. Mussel were seeded in summer, with the same mean total weight and shell length for both species. At the end of the experiment, shell length (SL), condition index and gonadosomatic index were compared over month, depth and species. Highly significant differences were found in shell length between month and depth and between month and species (p < 0.05). The linear relationship between the gonad weight and wet meat weight in M. chilensis present a higher gonad weight for the same wet meat weight than M. galloprovincialis. It can be concluded that at the end of the harvest size cultivation M. chilensis presents a greater gonad weight, condition index and gonadosomatic index.

70 show abstract
0044-8486 * * 30015579
Publication date: Available online 25 March 2019

Source: Aquaculture
Author(s): Esther Rubio-Portillo, Adriana Villamor, Victoria Fernandez-Gonzalez, Josefa Antón, Pablo Sanchez-Jerez

Changes in bacterial assemblages along an environmental gradient determined by the distance to aquaculture installations were analysed, using denaturing gradient gel electrophoresis to assess the influence of fish farming on marine sediments. Our findings show that changes in the structure of the bacterial community are a useful indicator for determining the environmental impact of aquaculture farms, due to the rapid response to changes in nutrient load, and could be an alternative strategy for monitoring programmes. Delta and Epsilonproteobacteria linked to the sulphur cycle were detected in the sediments beneath the cages. Since these groups were not found in the sediments at control stations, they serve as indicators for assessing the impact of the organic load from fish farming on marine sediments.

71 show abstract
0044-8486 * * 30015580
Publication date: Available online 23 March 2019

Source: Aquaculture
Author(s): Jun-Hwan Kim, Su Kyoung Kim, Young Baek Hur

We aimed to evaluate stress responses, acetylcholinesterase level, and immune responses of juvenile olive flounder Paralichthys olivaceus in a biofloc environment at different water temperatures. Juvenile P. olivaceus (mean weight 27.96 ± 3.07 g and mean length 13.4 ± 1.4 cm) in a biofloc environment were maintained at 20, 22, 24, 26, 28, and 30 °C for 2 weeks. The plasma cortisol level in P. olivaceus significantly increased at 28 and 30 °C at 1 and 2 weeks, signifying a stress response. The level of heat shock protein 70 (HSP 70) in the liver increased significantly at 28 and 30 °C at 1 week, and its level was maintained after 2 weeks at 28 °C, but significantly decreased at 30 °C. The HSP 70 level in the gills was significantly increased at 30 °C after 1 week and at 28 and 30 °C after 2 weeks. The level of acetylcholinesterase (AChE) in the liver was significantly inhibited at 30 °C after 1 week and at 28 and 30 °C after 2 weeks. The AChE level in the gills did not change significantly after 1 week, but was significantly inhibited at temperature>28 °C after 2 weeks. In terms of immune responses, the immunoglobulin M level and lysozyme activity in the plasma significantly decreased at 28 and 30 °C after 1 and 2 weeks. The results of the present study indicate that temperatures 28 °C or higher induce stress responses, change the neurotransmitter level, and alter immune responses of P. olivaceus maintained in a biofloc environment.

72 show abstract
0044-8486 * * 30015583
Publication date: Available online 26 February 2019

Source: Aquaculture
Author(s): Jia-Yun Yao, Jian-Lin Guo, Cheng-Sai Zang, Guo-Qiang Mi, Yong-Yi Jia, Wen-Lin Yin, Zheng Cao, Yan-Chun Xia, Xiao-Yi Pan, Ling-Yun Ling, Chun-Feng Wang, Zhi-Min Gu, Jin-Yu Shen

The main purpose of the present study was undertaken to isolate bioactive substances from microbial secondary metabolites of Streptomyces gilvosporeu AXY-25 and to determine their antiparasitic effect against Ichthyophthirius multifiliis. A pure compound showing strong anti- I. multifiliis activity was isolated from a culture of S. gilvosporeu AXY-25 by using the method of bioassay-guided isolation. The chemical structure of the active compound was confirmed as natamycin (NAT) by spectral analysis (EI-MS, 1H NMR and 13C NMR). An in vitro anti-parasitic assay demonstrated that 100% of theronts were killed with a concentration of 25.0 mg L−1 NAT for 4 h with an effective concentration (EC50) (95% CI) at 10.9 (10.7–11.1) mg L−1. Similiary, all tomonts were killed by a dose of 25.0 mg L−1. An in vivo anti-parasitic assay showed that the number of I. multifiliis trophonts on the surface of hybrid Erythroculter ilishaeformis in the NAT-treated group were markedly lower when compared to the control group (p < 0.05). Mortality in the 25.0 mg L−1 NAT-treated group was 36.7% at day 10. Mortality in the control group due to the I. multifiliis infection was 83.3% by day 10. In addition, the survival rate and reproduction of tomonts in the 25.0 mg L−1NAT treated group were markedly lower than those in the control group (p < 0.05). The results of the acute toxicity of NAT indicated that NAT was safe to use on hybrid E. ilishaeformis, the median lethal concentration (LC50) was 508.6 mg L−1.

73 show abstract
0044-8486 * * 30041766
Publication date: Available online 8 April 2019

Source: Aquaculture
Author(s): Zhen Zhang, Weiwei Zhang, Zhenguo Hu, Chenghua Li, Yina Shao, Xuelin Zhao, Ming Guo

The synergistic effect of pathogen infection and environmental change cause a disease outbreak in many marine animals, including skin ulceration syndrome (SUS) in sea cucumber (Apostichopus japonicus). Emerging evidence has also linked the important roles of gut microbiota in influencing disease among invertebrates. However, the connection between them is largely unknown. Here, we first conducted Illumina sequencing of the bacterial 16S rRNA gene to investigate the common alteration of the hindgut microbiota in SUS-diseased sea cucumber under four different stress conditions (high temperature, mechanical damage, nitrite-N, and ammonium) combined with Vibrio splendidus exposure. Results showed that the abundances of Firmicutes, Actinobacteria, and Deltaproteobacteria in each environmental stress group were lower, and the gut microbial diversity profoundly declined. The mechanical damage group had the lowest decrease compared among the environmental stress groups. Under environmental stress, a significant increase in keystone species, especially Flavobacteriaceae, Pelagimonas, Vibrio splendidus, Vibrio cyclitrophicus, and Bacillus cereus, was also detected. At the same time, the abundance of V. splendidus was higher in the four environmental stress groups than in the V. splendidus immersion group. The abundance of V. splendidus was the highest in the mechanical damage group. Kyoto Encyclopedia of Genes and Genomes analysis indicated that immune system and cell communication (focal adhesion, tight junction, and adherens junction) pathways significantly decreased in each stress group. Our results confirmed that complex environmental factors destroy intestinal flora and provided a global understanding of the environmental factors that induce disease in sea cucumber.

74 show abstract
0044-8486 * * 30041768
Publication date: Available online 8 April 2019

Source: Aquaculture
Author(s): Fulin Sun, Youshao Wang, Chunzhong Wang, Li Zhang, Kang Tu, Zhipeng Zheng

Although the microbial ecology of aquaculture systems is receiving increasing attention, the composition and controlling factors of aquaculture microbes has yet to be determined. This study explored the bacterial community present in water, sediment and intestine samples from an aquaculture site using high-throughput sequencing. The correlation between this bacterial community and environmental factors provides a reference for the environmental regulation of aquaculture sites. The dominant bacteria recorded from sediment, water, and intestine samples were Proteobacteria, Bacteroidetes, Cyanobacteria, Acidobacteria, Actinobacteria, and Firmicutes. Approximately 72.5% and 48.2% OTUs (operational taxonomic units) from the intestines of 17 cultured species were identical to those present in sediment and water samples, respectively. This finding indicated that sediment and water are major sources of intestinal microbes. Welch's t-test test found that the dominant microbial taxa differed significantly among sediment, water, and intestine samples, and that each of these environments has unique dominant microbial taxa that are closely related to their habitats. Principal component analysis showed that sediment, water, and intestine samples collected at different sites were clustered together and similar environments exhibited similar microbial community structures. This research examined the relationship between the intestinal microbes of multiple cultured organisms and the culture environment. Canonical correlation analysis revealed that environmental parameters, such as pH, COD, temperature, salinity, nitrite, and nitrate regulate the composition of microbial community structures. Nitrites and nitrates were significantly positively correlated to potential pathogens, such as Vibrio, Photobacterium, Tenacibaculum, and Mycobacterium, thereby providing a scientific theoretical basis for water quality regulation and disease prevention in aquaculture sites.

75 show abstract
0044-8486 * * 30041769
Publication date: Available online 8 April 2019

Source: Aquaculture
Author(s): Patharapol Piamsomboon, Nicole Sirisopit Mehl, Sudson Sirivaidyapong, Janenuj Wongtavatchai

Methods for milt collection and chilled preservation, hormone-induced spawning and artificial fertilization were studied in Nile tilapia Oreochromis niloticus. Milt samples were selected from 5 male brooders. Each milt sample was divided into 4 treatments; 3 treatments were centrifuge-washed with 0.85% normal saline solution (NSS), and then added with the extenders (1) freshwater fish saline (FFS) or (2) modified fish Ringers solution (MFS), or without an extender as (3) NSS (control), while the fourth treatment was the unwashed control. Milt samples treated with either extender at 4 °C presented a sufficient sperm motility score (≥ 3) and sperm viability (≥ 70%) for up to 20 h post-collection. For female brooders, gonadotropin-releasing hormone analog (GnRHa) was used to induce spawning. The highest number of females spawned and a pseudo-gonadosomatic index were observed in groups that received two GnRHa injections (15 and 30 μg kg−1, 8 h interval) with an oral administration of a dopamine antagonist (5 mg kg−1). Artificial fertilization was performed with fresh and 20 h chilled-storage milt. Mean fertilization rates for the fresh and chilled milt fertilized groups were 83.6 ± 7.2% and 42.3 ± 5.1%, respectively, with hatching rates of 67.5 ± 3.5% and 28.3 ± 6.8%, respectively. Nevertheless, the development of fish larvae from both groups was comparable. This study indicated that artificial fertilization using chilled milt and GnRHa-induced-spawn produced healthy tilapia fry. Thus, the procedures facilitate breeding programs of Nile tilapia in pair mating selection and distribution of genetic materials.

76 show abstract
0044-8486 * * 30041770
Publication date: Available online 8 April 2019

Source: Aquaculture
Author(s): Guoxia Wang, Kai Peng, Junru Hu, Cangjin Yi, Xiaoying Chen, Haomin Wu, Yanhua Huang

Defatted black soldier fly larvae meal (DBSFLM) has been shown a promising fish meal (FM) substitute in diets for turbot, rainbow trout, Jian carp, Pacific white shrimp and Atlantic salmon, but it has not been examined as an alternative protein source in Japanese seabass (Lateolabrax japonicus) diets. A 56-day feeding trial was conducted to assess the effects of partial replacement of dietary FM with DBSFLM on the growth performance, whole body composition, blood metabolites, digestive enzyme activities, hepatic and intestinal histomorphology, and lipid metabolism related genes expression of juvenile L. japonicus. Five isoproteic (39%) and isolipidic (11%) diets were formulated by replacing 0% (FM), 16% (DBSFLM16), 32% (DBSFLM32), 48% (DBSFLM48) and 64% (DBSFLM64) of fish meal. Each diet was randomly assigned to triplicate groups of 30 fish per tank. Fish were fed two times daily to apparent satiation. Results showed that growth performance, somatic indexes, hepatic and intestinal histomorphology, and the intestinal antioxidant and immunity indexes of fish were not affected (P > 0.05) by dietary treatments. Fish consuming DBSFLM48 and DBSFLM64 had higher (P < 0.05) feed intake, but lower (P < 0.05) whole body ash content and ash retention along with serum concentrations of total cholesterol, triacylglycerol, high density lipoprotein cholesterol and malondialdehyde than those fed FM. DBSFLM inclusion did not alter activities of hepatic trypsin, lipase and amylase, but increased (P < 0.05) activity of intestinal lipase for fish fed DBSFLM48 and DBSFLM64 than those fed FM. Relative genes expression were up-regulated (P < 0.05) in hepatic lipoprotein lipase for fish fed DBSFLM64 and in hormone sensitive lipase for fish fed DBSFLM32, DBSFLM48 and DBSFLM64, whereas down-regulated (P < 0.05) in fatty acid synthase for fish fed DBSFLM diets than those fed FM. It was concluded that the replacement of dietary FM with DBSFLM up to 64% level did not alter growth performance, hepatic and intestinal histomorphology of L. japonicus. The increased feed intake, reduced blood lipid and inhibited hepatic lipid deposition suggest that DBSFLM can be a desirable protein alternative source as a replacement of fish meal in L. japonicus diets.

77 show abstract
0044-8486 * * 30071226
Publication date: Available online 12 April 2019

Source: Aquaculture
Author(s): Jee Eun Han

This study describes the amoeba (order Dactylopodida) infection in Pacific white shrimp Litopenaeus vannamei cultured in an anonymous shrimp hatchery, located in North America. The diseased shrimp grossly exhibited reduced appetite, lethargy, respiratory distress, eroded carapace, and blackened gill. Histopathology examination revealed a massive amoeba infection (mostly in trophozoite form) mainly in the gill, but also other organs, such as the antennal gland, lymphoid organ, appendages, and nerve cord of the studied shrimp. The irregular-shaped trophozoites, with the prominent centrally located nucleolus and the basophilic parasome, suggested that this parasite is related to the Paramoeba sp. (order Dactylopodida). Analysis of the small subunit rRNA sequence showed 100% sequence similarity with Paramoeba spp. (or Neoparamoeba spp.) from several aquatic crustaceans and echinoderm species, such as sea urchins, crabs, and lobsters. The sequence also matched with other amoeba species, such as Korotnevella sp. and Pseudoparamoeba sp. (order Dactylopodida). Diagnostic in situ hybridization and PCR assays were developed as the initial screening methods for the detection of the amoebic infection in cultured shrimp. This report is the first to describe the amoeba (Paramoeba-like sp.) infection in penaeid shrimp.

78 show abstract
0044-8486 * * 30071227
Publication date: Available online 12 April 2019

Source: Aquaculture
Author(s): Mechlaoui Marwa, Dominguez David, Robaina Lidia, Geraert Pierre-Andre, Kaushik Sadasivam, Saleh Reda, Briens Mickael, Montero Daniel, Izquierdo Marisol

The present study aimed to determine the effects of dietary inclusion of selenium (Se) in the form of either inorganic Se (sodium selenite, NaSe) or organic Se (hydroxy-selenomethionine, OH-SeMet) on gilthead seabream (Sparus aurata). Triplicate groups of 150 fish each (6.2 ± 0.04 g initial body weight) were distributed in 15 tanks and fed one of five experimental diets for 63 days. A control diet (C) without Se supplementation (0.8 mg Se/kg diet), was formulated and served as a basal diet for the other 4 experimental feeds, supplemented with either 0.2 or 0.5 mg Se/kg supplied in the form of NaSe or OH-SeMet. Fish growth performance, biochemical composition of liver and muscle and Se content, malondialdehyde (MDA) concentration in muscle and hepatopancreas, hepatocyte morphology and lysozyme activity in the serum were studied. Furthermore, expression of related hepatic genes, such as manganese superoxide dismutase (Mn-sod), catalase (cat), heat shock protein 70 (hsp70), and glutathione peroxidase (gpx) was also analyzed. After the trial, fish were exposed to an acute and chronic confinement stress. Blood samples for cortisol analysis were taken at 0 and 2 h after the acute stress and after 7 days of chronic stress.
The highest growth rate was observed in fish fed OH-SeMet at a level of 0.2 mg/kg, but with no significant difference with fish fed the control diet with no-added Se. The lowest growth was observed in fish fed NaSe up to 0.5 mg/kg. Increase in dietary Se, particularly in the form of OH-SeMet, led to an increase in Se contents in liver and muscle. Furthermore, dietary inclusion of OH-SeMet, led to a significant (p < .05) reduction in MDA in both liver and muscle. Se inclusion as NaSe at 0.2 mg/kg was not as effective as organic Se to improve muscle oxidative status. Dietary inclusion of Se at 0.2 mg/kg significantly reduced plasma cortisol after 2 h of acute stress, regardless of the Se form fed. Lysozyme activity measured in the serum was decreased with the increase in dietary Se supplementation.
In summary, supplementation of Se up to 0.2 mg/kg (1–1.1 mg/kg analyzed dietary Se), particularly in the form of OH-SeMet, led to a beneficial effect on growth, maintenance of hepatic morphology and improved protection of juvenile gilthead seabream from acute or chronic stress. Besides, OH-SeMet was found to be more effective than NaSe in protection against oxidative stress in fish muscle.

79 show abstract
0044-8486 * * 30071230
Publication date: Available online 10 April 2019

Source: Aquaculture
Author(s): Xiao Xie, Rongrong Ma, Dong Qian, Youbin Yu, Xiao Liu, Yuhua Lei, Yanning Lin, Fei Yin

Nibea albiflora (Yellow drum) was discovered to be highly resistant to the infection of Cryptocaryon irritans a lethal ciliate protozoa parasite during disease outbreak. Investigation of miRNAs which post-transcriptionally regulate genes will deeper our understanding of regulation of immune response against infection. In this study, we challenged N. albiflora with C. irritans at median lethal concentration (2050 theronts/g fish). Skins from infected and controlled fish were sampled at 24 h and 72 h for miRNA sequencing. In total, we identified 180 known and 71 novel miRNAs, in which 30 miRNAs were significantly affected by infection, 19 were influenced by time and 16 significantly affected by the interaction between time and infection. Totally, 7396 genes were predicted as targeted regulated by infection differential expressed genes. The genes were significantly enriched in C-type lectin receptor pathway, MAPK signaling pathway and mTOR signaling pathway which closely related to antigen recognition, presentation and downstream signal transduction for immuno-activation. Overall, our data suggest that most of miRNAs were intensively regulating gene expression involved in C-type lectin receptor pathway, MAPK signaling pathway and mTOR signaling pathway rather than directly involve in immunological factor regulation during immune response against parasite infection.

80 show abstract
0044-8486 * * 30095095
Publication date: Available online 16 April 2019

Source: Aquaculture
Author(s): Inácio Mateus Assane, Katia Suemi Gozi, Gustavo Moraes Ramos Valladão, Fabiana Pilarski

Individual minimum inhibitory and bactericidal concentrations (MIC and MBC) of thiamphenicol (TAP), florfenicol (FFC) and oxytetracycline (OTC) were determined for 49 strains of bacteria isolated from different freshwater fish during disease outbreaks in Brazil. Posteriorly, the in vitro activity and in vivo therapeutic effectiveness of TAP combined with FFC against Aeromonas hydrophila isolated from diseased Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) were evaluated. The in vitro effect of this combination (in terms of the fractional inhibitory concentration index – FICI) was determined by checkerboard microdilution assay, while in vivo analysis was performed via the administration of single doses of TAP (G1: 10 mg/kg), FFC (G2: 10 mg/kg) and selected combinations thereof (G3: 5 mg/kg TAP +2.5 mg/kg FFC, and G4: 2.5 mg/kg TAP +1.25 mg/kg FFC), correspondent to FICI deduction, by gavage to Nile tilapia (70 ± 12 g) challenged by intraperitoneal injection with A. hydrophila. TAP, FFC, and OTC application demonstrated in vitro activity against 55.1%, 71.43% and 55.82% of the evaluated bacteria, respectively. Aeromonas spp. were sensible to the antibiotics both individually and combined (FICI ≤0.75). The two combinations of TAP and FFC (G3 and G4) were as effective in vivo as the recommended individual doses of each antibiotic (G1 and G2), showing greater survival (p < .05) than the unmedicated group (G5). A total of 85.93 ± 5.13% of fish medicated with 62.5% less antibiotics than are currently used to control aeromoniosis survived. These findings demonstrate the potential utility of combination antimicrobials (CA) involving TAP and FFC as an effective approach with which to control aeromoniosis using lower overall doses of antimicrobials with similar efficacy, which may contribute to a reduction in their use without reducing their therapeutic effect during outbreaks in fish farms.

81 show abstract
0044-8486 * * 30095096
Publication date: Available online 16 April 2019

Source: Aquaculture
Author(s): Rafael Junnar P. Dumalan, Karen Grace V. Bondoc, Marie Antonette Juinio-Meñez

Mariculture-impacted areas contain organically-enriched sediments that sea cucumbers could potentially thrive on. The viability of growing sandfish (Holothuria scabra) to marketable size (>300 g) in a milkfish (Chanos chanos) fish farm area was investigated through simultaneous pen grow-out experiments in a fish farm and a seagrass site. We determined the growth and survival of juveniles in conjunction with environmental parameters during each experiment. Smaller juveniles (6.7 g ± 0.7 g) stocked in the fish farm site experienced mass mortality within 15 days whereas survival was low in the seagrass site (12%). In contrast, survival of larger juveniles (57.4 ± 4.3 g) was high in the fish farm (49%) and not significantly different from the seagrass site (63%). Moreover, absolute growth rates (AGR) were much higher in the fish farm (1.2 ± 0.2 g m−2) than those in the seagrass site (0.2 ± 0.1 g m−2). The fish farm site supported two-fold higher biomass, and sandfish reached marketable sizes (> 300 g) within 7 months primarily due to a higher total organic matter and chloroplastic pigment equivalent in the sediment. AGR was negatively correlated with strong water movement and positively correlated with total suspended solids and salinity. Additionally, temporal variability in AGRs indicates that sandfish is highly sensitive to decrease in salinity due to heavy precipitation. An intermediate grow-out culture of juveniles to>50 g in a seagrass area was essential prior to release in the fish farm site. Results provide new insights into the coupling of the environmental factors and life stage of the organism in mediating grow-out success.

82 show abstract
0044-8486 * * 30095100
Publication date: Available online 15 April 2019

Source: Aquaculture
Author(s): Bernat Morro, Pablo Balseiro, Amaya Albalat, Cindy Pedrosa, Simon Mackenzie, Shu Nakamura, Munetaka Shimizu, Tom O. Nilsen, Harald Sveier, Lars O. Ebbesson, Sigurd O. Handeland

Photoperiod is thought to be the main zeitgeber that induces smoltification in salmonids. However, its effects on the smoltification of rainbow trout (Oncorhynchus mykiss) are not fully understood and no published data documents the effects of the photoperiod regime currently used commercially, continuous light (LL). The present study compared the effect of four different photoperiod regimes (i.e. advanced phase photoperiod (APP), delayed phase photoperiod (DPP), LL and simulated natural photoperiod (SNP)) on the smoltification and growth of juvenile rainbow trout during their freshwater phase of winter-spring and the following summer post smolt phase. Smoltification was evaluated by monitoring gill Na+,K+–ATPase (NKA) activity and transcription of NKA α-subunit isoforms 1a and 1b, and Na





cotransporter 1a. Growth was measured as specific growth rate of both length and weight, and through molecular growth proxies such as the levels of circulating insulin-like growth factor 1 (IGF-I) in plasma and transcription of igf-I, igf binding protein 1b (igfbp1b), growth hormone receptor 1 (ghr1) and cathepsin L (ctsl) in the liver. Results indicate that APP induces a longer smolt window and higher levels of plasma IGF-I in both freshwater and seawater (two months post transfer), while DPP led to a shorter smolt window, lower plasma IGF-I levels in freshwater and seawater, an earlier decrease in liver igf-I and ctsl transcription in freshwater (as seen by modelling over time) and lower specific growth rate in freshwater. The transcription analysis of osmoregulatory genes complemented NKA activity and allowed for the detection of a transient response to light and of differences between the osmoregulatory capacity of parr and desmolted fish. Furthermore, an upregulation of the liver transcription of igf-I, ghr1 and ctsl was found in all treatments during the smolt window, which corresponded to the periods with highest growth. Finally, both plasma IGF-I and liver igf-I in seawater were found to be significantly correlated to fish growth in seawater. However, our data did not show that plasma IGF-I prior to seawater transfer could be used as a reliable predictor of growth in seawater. Overall, and especially when compared with other salmonid species, photoperiod seems to be a weaker inducer of smoltification in rainbow trout, according to the parameters that were tested, suggesting that other environmental cues might be more important drivers of this process.

83 show abstract
0044-8486 * * 30095102
Publication date: Available online 13 April 2019

Source: Aquaculture
Author(s): Jiawei Hong, Xu Chen, Sixun Liu, Zhengyi Fu, Mingyang Han, Yifu Wang, Zhifeng Gu, Zhenhua Ma

To understand the effects of fish density on water quality and physiological changes of golden pompano (Trachinotus ovatus) fingerlings during transportation, fish were stocked at three densities (27 kg/m3, 54 kg/m3 and 81 kg/m3) for 8 h using the method of anesthesia hypothermia in sealed containers. The fish reared in the recycling system were used as the control. The pH of water at three fish densities was significantly lower than the initial value and decreased gradually with the increase of fish density. The lowest pH and ammonia nitrogen were found in the 81 kg group, reaching 6.24 and 0.08 mg/L, respectively. The liver catalase activity increased gradually but was still significantly lower than that in the control. The liver peroxidase activity fell gradually corresponding to the increase of fish density but was higher than that in the control. Fish density during transportation did not affect the lactate dehydrogenase activity in the liver. After 8-h transportation, fish in all three groups had a lower level of glucose and creatinine in the serum than in the control fish. The content of serum cortisol soared after transportation, but no significant difference was found among three fish densities. Glutamate pyruvate transaminase and glutamic oxaloacetic transaminase activities in the serum had a similar pattern to those of the fish in the control and showed a gradual reduction with increasing fish density. Fish density during transport significantly affected water quality (e.g., pH and NH3-N) and liver function. Our results indicate that the fish density of 81 kg/m3 is safe to transport golden pompano fingerlings for 8 h.

84 show abstract
0044-8486 * * 30125210
Publication date: 30 May 2019

Source: Aquaculture, Volume 507
Author(s): Pollyanna E. Hilder, Stephen C. Battaglene, Nathan S. Hart, Shaun P. Collin, Jennifer M. Cobcroft

We examined Southern bluefin tuna, Thunnus maccoyii, larvae to identify specific retinal adaptations that would indicate both important parameters for culture and larval ecology in the wild. Plastic resin histology, microspectrophotometry and behavioural feeding responses were used to describe visual development. Thunnus maccoyii larvae reflected the visual morphogenesis template commonly observed in many other marine fish species exhibiting indirect development. First-feeding (3 days post-hatching, [dph], 3.4 mm standard length [SL]) larvae possessed tightly packed single cone photoreceptors. Rods and twin cones were present in the retina in post-flexion larvae (21 dph, 8.39 mm fork length [FL]) with cone mosaic patterns observed in juveniles (30 dph, 21 mm FL). Based on the spacing of adjacent photoreceptors and focal length, first feeding larvae had a maximum theoretical visual acuity of 1.23 ± 0.11° that decreased to 0.14 ± 0.02° at 30 dph. Thunnus maccoyii displayed high cell density in the ventral retinal region (cones, bipolar and horizontal cells), a low convergence of cone cells to ganglion cells throughout the retina during larval development (1.1 ± 0.2 to 1.4 ± 0.3 at 3 dph and 30 dph, respectively), and early development of retinal pigment epithelium (RPE) migration. Microspectrophotometry showed twin cone visual pigments maximally sensitive to light in the blue-green part of the visual spectrum (wavelength of maximum absorption [λmax] of 494 nm, 507 nm and 524 nm), and behavioural experiments showed they fed preferentially at these wavelengths. Increased retinal cone densities in the ventral region indicated a localized region specialized for acute vision for prey and predator detection in the upward direction (dorsal plane) at an early age, representing a possible adaptation to life in deeper oceanic waters. The apparent high acuity and photopic sensitivity observed in T. maccoyii is hypothesised to be associated with the ability to feed in low light conditions. This has important practical considerations in determining lighting regimes for culture of T. maccoyii and possibly for other tuna species.

85 show abstract
0044-8486 * * 30125211
Publication date: 30 May 2019

Source: Aquaculture, Volume 507
Author(s): Lixia Xie, Siqi Chen, Chaorui Yao, Dapeng Li, Li Li, Rong Tang

Nitrite pollution is one of the most frequently reported problems in aquaculture. However, little is known for its toxic mechanisms. The present study was conducted to investigate the effects of nitrite on antioxidant capacity, ER stress (Endoplasmic Reticulum stress) and apoptosis in grass carp (Ctenopharyngodon idella). Fish were exposed to nitrite (0, 8, 25, 50 mg L−1) for 96 h, the genes expression, histological section and antioxidant enzyme activity were assayed. The results show that the expression of ER stress marker gene grp78 was significantly up-regulated in liver, the expression of PERK pathway genes perk, eif-2α, atf4 and chop have changed, the superoxide dismutase (SOD) activity decreased while the catalase (CAT) activity increased significantly in serum, fish liver shows severe damage in nitrite exposure. Grass carp liver cells (L8824) were incubated in nitrite solution (0, 2.5, 10, 100 mg L−1) for 24 h. Significant decrease in cell viability and apoptosis were observed in the treatment, the expression of ER stress marker gene grp78 was up-regulated, moreover the PERK pathway genes perk, eif-2α, atf4 and chop were up-regulated in 2.5 mg L−1 and 10 mg L−1. The expression of the proapoptotic gene bax was significantly up-regulated, and the expression of the inhibitory gene bcl-2 was significantly down-regulated, therefore the ratio of bax/bcl-2 was up-regulated. These results indicate that in the nitrite-induced acute liver injury of grass carp, ER stress response may activate antioxidant system as a protection.

86 show abstract
0044-8486 * * 30125212
Publication date: 30 May 2019

Source: Aquaculture, Volume 507
Author(s): Stefania Caroline Claudino da Silva, Bruno Lala, Caio Henrique de Oliveira Carniatto, Christiano Rodrigues Schamber, Carlos Souza Nascimento, Graciela Lucca Braccini, Carla Porto, Gabriel Roldi, Fernanda Tanamati, Eliane Gasparino

Fumonisins (FB) are mycotoxins produced during secondary metabolism of Fusarium verticillioides and Fusarium proliferatum fungi and can prevent animal performance. In this study, the hypothesis that fumonisin affects the expression of IGF-1 and GHR genes in Nile tilapia (Oreochromis niloticus) fingerlings and juveniles was tested. Nile tilapia fingerlings and juveniles received diets with and without the inclusion of fumonisin (50 mg FB kg−1 of feed) to evaluate their effects on weight gain (WG), feed intake (FI), feed conversion (FC) and mRNA expression of GHR and IGF-1 in the liver. The fumonisin-free diet was used as a control treatment. All variables were evaluated after 20 days of treatment. The diet containing 50 mg FB kg−1 of feed significantly reduced WG (P < 0.0001) and worsened FC (P < 0.0001) for fingerlings, but did not affect FI. For juveniles, the inclusion of fumonisin did not affect FI, FC and WG. GHR and IGF-1 mRNA expression of both fingerlings and juveniles was significantly reduced by the inclusion of fumonisin (P < 0.0001). These results indicate that fumonisin affects the hepatic expression of GHR and IGF-1 in Nile tilapia, but the phenotypic effect is more evident in fingerlings.

87 show abstract
0044-8486 * * 30125213
Publication date: Available online 18 April 2019

Source: Aquaculture
Author(s): K.K.T. Nuwansi, A.K. Verma, G. Rathore, Chandra Prakash, M.H. Chandrakant, G.P.W.A. Prabhath

An experiment was carried out for 60 days to utilize the phytoremediated aquaculture wastewater for production of Gotukola (Centellaasiatica (L.)), a leafy vegetable as well as a traditional medicinal plant; and koi carp (Cyprinuscarpiovar. koi), a popular ornamental fish with high market demand. Treated water and borewell water were mixed in different combinations namely 100:0 (T1), 75:25 (T2), 50:50 (T3) and 25:75 (T4) to produce four treatments. Additionally three controls were also maintained to compare the efficiency of the treatments. These were Control 1 consisting of hydroponic component with plant (C1), Control 2 consisting of hydroponic component without plant (C2) and Control 3 with only borewell water (C3). Plants in Control 3 were used to compare the efficiency of plant growth in field condition. On the basis of plant growth parameters viz., leaf width, number of leaves, number of plant-lets, number of runners, length of runners and the final yield, T1 showed the best performances. However, it was not significantly different from T2 and T3 except the final yield. Best growth performance of fish viz., weight gain, length gain, feed conversion ratio (FCR), feed efficiency ratio (FER), protein efficiency ratio (PER), and specific growth rate (SGR) was observed in T3. Considering the fish colour, there was no significant difference between the treatments for chroma and hue values, but best chroma values were obtained in T1 followed by T2 > T3. This denotes that the treated wastewater positively affects the fish colour by pigment enhancement. The efficiency of the aquaponics was judged by percentage nutrient removal and biofilter performance. The highest removal of nitrite-N (92.34%), nitrate-N(70.55%) and ammonia-N (71.36%) were observed in T1 and it was positively related with the plant growth. The highest phosphate-P removal percentage (59.78%) and best biofilter performance (3.24 g−
3 day−1) were observed in T3 and also, comparatively a higher plant growth was obtained in T3 than T4 and C1. Considering the overall parameters viz., fish growth, fish health, plant growth and water quality parameters, equal proportion of treated wastewater and borewell water (T3) was found to be the most effective combination. The results revealed that the phytoremediated aquaculture wastewater can be sustainably reused in aquaponics for fish and plant production.

88 show abstract
0044-8486 * * 30125214
Publication date: Available online 18 April 2019

Source: Aquaculture
Author(s): Erick Perera, Paula Simó-Mirabet, Hyun Suk Shin, Enrique Rosell-Moll, Fernando Naya-Catalá, Verónica de las Heras, Juan Antonio Martos-Sitcha, Vasileios Karalazos, Eva Armero, Marta Arizcun, Elena Chaves, Concepción Berbel, Manuel Manchado, Juan Manuel Afonso, Josep Calduch-Giner, Jaume Pérez-Sánchez

Farmed gilthead sea bream (Sparus aurata) is able to grow efficiently with new feed formulations based on plant ingredients. Here, two experimental diets with standard and high inclusion levels of plant ingredients were formulated to assess the suited use of plant-based diets in fish with different growth genetic backgrounds. To pursue this issue, a long-term feeding trial (12-months) was conducted with fish (17 g initial body weight) of 16 families coming from the broodstock of PROGENSA project, that were grown communally in the IATS-CSIC experimental facilities. All fish in the study (2545) were PIT-tagged, and their pedigree was re-constructed with 96% success by using a SMsa1 multiplex of 11 microsatellites, which revealed the main parents contributions of 5 females and 6 males. Each diet was randomly assigned to replicate 3000 L tanks, gathering each replicate a similar family composition through all the feeding trial. Data on growth performance highlighted a strong genetic effect on growth trajectories, associated with enhanced growth during winter in fish selected for faster growth. No main dietary effects were found on growth rates or condition factor, and regression-correlation analyses of growth rates across families on both diets suggest that genome by diet interaction was weak, while genetic variation accounted for most of the growth phenotypic variation. Hepatosomatic index (HSI) and mesenteric fat index (MSI) of five families, covering the growth variability of the population, were regulated nutritionally and genetically, but without statistically significant genome by diet interactions. Fish from faster growing families showed shorter intestines after being fed the control diet, but this phenotype was masked by the enriched plant-based diet. Collectively, the results demonstrate that selection for faster growth is associated in gilthead sea bream with different growth trajectories and a high diet flexibility and intestine plasticity.

89 show abstract
0044-8486 * * 30125215
Publication date: Available online 17 April 2019

Source: Aquaculture
Author(s): Ehsan Ahmadifar, Najmeh Sheikhzadeh, Kambiz Roshanaei, Narges Dargahi, Caterina Faggio

Effects of the dietary ginger (Zingiber officinale) on growth, some immunological and biochemical parameters and gene expression related to growth, immunity and antioxidant systems in zebrafish were studied. Immune parameters such as immunoglobulin level, alternative complement activity, and lysozyme activity were significantly higher in treatment groups fed with 2% and 3% ginger than the control fish. Amylase activity also increased significantly in the same pattern as the immunological parameters. Catalase and lysozyme mRNA expression levels representatives of antioxidant and immune genes respectively, were up-regulated in the fish fed with 3% ginger. Conversely, expression of gene encoding ghrelin was down-regulated in all treatment groups compared with the control group. Present study suggests that powdered ginger especially at 3% might augment some immunological and biochemical responses as well as expression of genes relevant to antioxidant and immune systems in zebrafish.

90 show abstract
0044-8486 * * 30125216
Publication date: Available online 17 April 2019

Source: Aquaculture
Author(s): Zhe Pan, Qin-Feng Gao, Shuang-Lin Dong, Fang Wang, Xu-Yang Jiang, Gong Zhang, Kun Zhao

Although mariculture activities play a significant role in coastal carbon cycling, there is a lack of research on sedimentary organic carbon (SOC) in mariculture areas.
In this study, remineralization of SOC in Ailian Bay, China, and an adjacent offshore control area was analyzed by combining sediment and pore water analyses, to investigate the effects of mariculture on the preservation of SOC and the related mechanisms. The significant higher total organic carbon (TOC) to sediment surface area in abalone culture area (0.74 ± 0.10 mg·m−2) than those in control area (0.59 ± 0.06 mg·m−2) suggested the maricultural activities may increase the preservation efficiency of SOC. During anaerobic incubations, higher vertical profiles and production rates of ΣCO2 in pore water of sediments in the abalone culture area than those in the control area indicated that maricultural activities may increase the rate of organic carbon remineralization. Furthermore, similar findings in dissolved organic carbon (DOC) suggested maricultural activities may increase the release of DOC in the sedimentary environment, which is an important supplement to the marine DOC pool. Additionally, the higher vertical concentrations and fluxes of the three major cations (i.e., K+, Ca2+, and Mg2+) coupled with the increased rate of SOC remineralization in the abalone culture area demonstrated that the maricultural activities strongly strengthened the formation of authigenic mineral. In conclusion, these findings suggested that maricultural activities play an important role in the coastal carbon cycle, significantly affecting the remineralization, preservation of SOC and the biogeochemical cycling of other important biogenic elements.

91 show abstract
0044-8486 * * 30125217
Publication date: Available online 17 April 2019

Source: Aquaculture
Author(s): Felipe C. Cabello, Henry P. Godfrey

In two recently published articles in Aquaculture, Mardones et al. (2018) discuss the emergent fish pathogen and cause of salmonid rickettsial syndrome (SRS), Piscirickettsia salmonis, while Avendaño-Herrera (2018) discusses the heavy use of antimicrobials in Chile to prevent and treat salmonid bacterial infections including SRS. Mardones et al. put forward a research agenda that focuses largely on P. salmonis and its relation to the biology of SRS. We believe a broader view of the problem would be beneficial. An extended examination of the scientific literature suggests that P. salmonis is likely an opportunistic environmental pathogen with low levels of virulence and pathogenicity and/or an endogenous pathobiont colonizing the normal salmonid microbiome. Multiplication of this bacterium and its ability to produce SRS is at least in part triggered by shortcomings in piscine husbandry that negatively affect salmonid health and well-being. This explanation is consistent with the limited efficacy of vaccines and antimicrobials in preventing and modifying the course of SRS, and suggests that efforts focused on geographical concentration of aquaculture sites; high densities of cultured fish at these sites; levels of nutrients and eutrophication; co-infections with bacteria, viruses and sea lice; excessive use of antimicrobials and other treatments for these infections; and climate change would deserve increased research consideration in the future. In their analyses and proposed research agendas, neither of these articles takes into account the negative effects of excessive and perhaps unnecessary antimicrobial use on piscine, human and environmental health as understood by the One Health paradigm.

92 show abstract
0044-8486 * * 30125218
Publication date: Available online 17 April 2019

Source: Aquaculture
Author(s): Zhengfeng Ding, Yuwei Yan, Yan Wu, Yinbin Xu, Qingguo Meng, Gongcheng Jiang

An epidemic of red gill disease with a high mortality rate recently occurred in the cultured oriental river prawn Macrobrachium nipponense in China. The prawns had flaccid bodies and gills were red in color with numerous black spots. By wet smear microscopy and negative staining, numerous membrane-bound plasmodia or degenerated spores were observed. Histological sections indicated the infection was limited to the gills. The gill filaments were filled with masses of mononuclear parasites, multinucleate and multicellular plasmodia and became enormously hypertrophic. Host encapsulation response and inflammatory foci with phagocytized parasite spores were evident. Transmission electron microscopy (TEM) analysis confirmed the gross plasmodia almost filling the entire space of gill epithelial cell. The intracellular parasite was a multinucleate plasmodium enclosed in a vacuole within the cytoplasm of the host cell. Large numbers of trophonts were visible in each plasmodium. High degree of vesiculation of early sporonts was evident. Scanning electron microscopy (SEM) and TEM observations all revealed characteristic tubular extension from the surface of a late sporont. We recognized the risk of associating the presence of a parasite with a particular pathology in the absence of total evidence that demonstrates an unequivocal link between the parasite, the perceived pathology and a clear disease manifestation that would be demonstrated by e.g. experimental studies. However, given the widespread importance of the host in aquaculture, it is necessary to provide this short report to highlight to other researchers and to the industry the potential for a new and emerging disease. It is hoped that this will lead to additional sightings of the condition and additional research to confirm the link between parasite and the pathology seen. It is our intention to complete life-cycle studies with to satisfy Koch's postulate.

93 show abstract
0044-8486 * * 30125219
Publication date: Available online 16 April 2019

Source: Aquaculture
Author(s): L. Vargas-Chacoff, J.L.P. Muñoz, J. Saravia, R. Oyarzún, J.P. Pontigo, M.P. González, O. Mardones, C. Hawes, J. Pino, S. Wadsworth, F.J. Morera

The aquaculture industry has many problems associated with bacteria, viruses, and parasites, and the stress caused by these infections can modulate the physiological response in fish. In Chile, the sea lice Caligus rogercresseyi constitutes a major problem affecting the Chilean salmonid industry, having a strong negative effect on salmon production. For this reason, the aim of this study was to investigate the neuroendocrine and stress response of the most commonly cultured salmonid species in Chile, the Atlantic salmon (Salmo salar) and the Coho salmon (Oncorynchus kisutch), which were experimentally infested with the sea lice Caligus rogercresseyi. We analyzed the monoamine response in the telencephalon, optic tectum, and hypothalamus, as well as cortisol levels in plasma. In the liver and muscle we analyzed the cellular response by measuring heat shock proteins (60, 70, 90) and glucocorticoid mRNA transcription. After 14 days post infection C. rogercresseyi infestation modified the neuroendocrine and stress response in Atlantic and Coho salmon, with Coho salmon presenting a faster and higher response than the Atlantic salmon.

94 show abstract
0044-8486 * * 30125220
Publication date: Available online 16 April 2019

Source: Aquaculture
Author(s): Gonzalo de Alba, Natália Michele Nonato Mourad, Juan Fernando Paredes, Francisco Javier Sánchez-Vázquez, José Fernando López-Olmeda

Control of reproduction is one of the key issues to extend tilapia aquaculture. In most fish species, reproduction is a rhythmic process which ensures that reproduction timing matches the most favorable environmental conditions to maximize the survival of offspring. Although the existence of daily spawning rhythms has been reported for a number of fish species, the daily rhythms in neuroendocrine factors along the BPG (brain-pituitary-gonadal) axis remains mostly unknown. The objective of this paper was to investigate the existence of daily rhythms in BPG gene expression and plasma sex steroids in tilapia (Oreochromis niloticus). To this end, 36 males and 36 females were kept in separate tanks at 29 ± 0.5 °C and in a 12 h:12 h light/dark cycle. After 4 weeks of acclimation, male and female tilapia were mixed into six groups at a female:male ratio of 6:6. Two weeks later, fish were anesthetized and sampled every 4 h during a 24-hour cycle, and blood, brain, pituitary, gonad and eggs were taken for later analyses. The expression levels of the genes from the brain (gnrh1, gnrh2, gnrh3, kiss2, gnih), pituitary (fshβ and lhβ), gonad (star, cyp11a, cyp17, cyp19a1a and amh) and eggs (zp3b and fyna) were analyzed by qPCR. ELISA was used to analyze testosterone and estradiol in male and female plasma, respectively, and maturation-inducing hormone (MIH) in plasma in both sexes. The results revealed timely-coordinated daily rhythms along the BPG axis of tilapia. The expression of the brain genes showed that their acrophase was distributed throughout the LD cycle. However, a coordinated and harmonious pattern of daily rhythms appeared on the following levels of the BPG axis. The peaks in expression of the pituitary genes were reached at night, while the gonadal genes and plasma sex steroids peaked in the light phase. These findings can be useful for improving breeding protocols for tilapia aquaculture, and for defining optimum timing for reproduction in captivity.

Green Open Access

Sherpa/Romeo info

Author can archive pre-print (ie pre-refereeing)
Author can archive post-print (ie final draft post-refereeing)
Author cannot archive publisher's version/PDF
  • Authors pre-print on any website, including arXiv and RePEC
  • Author's post-print on author's personal website immediately
  • Author's post-print on open access repository after an embargo period of between 12 months and 48 months
  • Permitted deposit due to Funding Body, Institutional and Governmental policy or mandate, may be required to comply with embargo periods of 12 months to 48 months
  • Author's post-print may be used to update arXiv and RepEC
  • Publisher's version/PDF cannot be used
  • Must link to publisher version with DOI
  • Author's post-print must be released with a Creative Commons Attribution Non-Commercial No Derivatives License
  • Publisher last reviewed on 03/06/2015

More Sherpa/Romeo information

APC Discount

For this journal no deals have been made concerning APC discount

More information on Open Access publishing


Journal Citation Reports (2017)

Impact factor: 2.710
Q1 (Fisheries (9/50))
Q1 (Marine & Freshwater Biology (17/106))

Scopus Journal Metrics (2017)

SJR: 1.152
SNIP: 1.580
Impact (Scopus CiteScore): 0.305
Quartile: Q1
CiteScore percentile: 92%
CiteScore rank: 15 out of 199
Cited by WUR staff: 1074 times. (2014-2016)

Similar journals  

Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.