Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Nutritious ponds : valorising waste using natural production
    Hermsen, Devi - \ 2020
    Wageningen University. Promotor(en): M.C.J. Verdegem, co-promotor(en): J.A.J. Verreth. - Wageningen : Wageningen University - ISBN 9789463952972 - 179

    These days understanding and predicting impacts of anthropogenic climate change caused by greenhouse gas emissions (rising temperatures and acidification of oceans), and exploitation of natural resources (overexploitation and waste production) on ecosystem dynamics is a major issue. With the world population increasing, there is demand to produce more food, which impinges with the wish to reduce waste output and lower the use of limited resources. Aquaculture has the potential to increase production by intensification, but to do so, the sector is facing major sustainability challenges. Two major issues hindering sustainable intensification are waste residues in pond culture water, and the use of capture fisheries derived fishmeal and fish oil in aquaculture diets as source of highly unsaturated omega-3 fatty acids (HUFA). This thesis advocates for developing the “nutritious pond concept” where the focus should shift from feeding the culture-animal, to feeding the whole system. In this way, a balanced food web develops, supporting production and good water quality. In this way, aquaculture production can be made more ecological while maintaining high production levels.

    In chapter 2, the contribution of HUFA from dietary fish oil and fishmeal, and the natural food web on shrimp production was determined. Fatty acid mass balances were computed to distinguish between formulated diet-based and primary production-based HUFA contribution. Absence of both fish oil and fishmeal in the formulated diet did not reduce shrimp production. However, shrimp fed diets lacking fish oil and fishmeal contained only half of the HUFA compared to control shrimp. In both dietary treatment groups, large dietary quantitative losses of the precursors ALA and LA were observed that were being used as energy source instead of HUFA synthesis. Whereas losses were also observed for EPA and DHA in the control group, there was a remarkable gain for these components in shrimp fed diets free of fish oil and fishmeal. Shrimp acquired at least 32 % of their EPA and 6 % of their DHA content from the algal-based food web. These findings strongly suggested that the pond’s natural food web produced HUFA that supports shrimp production.

    In chapter 3, the in situ produced HUFA was quantified per food web compartment. Seston was found to contain the highest HUFA content in the mesocosm, while biofloc dominated in terms of biomass. The total HUFA production in the mesocosms was a more than 600 % increase compared to the minimal HUFA-input in the tanks receiving HUFA-deficient diets, pinpointing de novo in situ production. Most of the formulated feed input resulted in organic matter biomass accumulation other than shrimp, as shrimp only retained 12 % of the organic matter input. This showed that the system as a whole is quite efficient in converting nutrient input into different food web compartment, but shrimp production alone is quite inefficient. With shrimp harvesting, only 25 – 27 % of the total mesocosm HUFA content is removed from the system. The majority of the nutrients, including de novo produced HUFA, remained in the food web. This exposed a major challenge on finding ways to reclaim those nutrients from the system in a more efficient way.

    This challenge was reinforced by the outcomes in chapter 4, focussing on nitrogen (protein), showing large amounts of total mesocosm nitrogen content could be found in food web compartments other than shrimp. Lowering the feed:fertilizer ratio of the mesocosm input by replacing 50 % of the formulated feed with carbon and nitrogen fertilizers (thus reducing protein input by half), lead to a 48 % increase of food web protein contribution to shrimp protein content. Total natural food protein contribution was estimated at 74 %. Feed conversion ratio was below 1.0 in all treatments and decreased with decreasing feed:fertilizer ratio down to 0.48. The nitrogen-to-protein conversion factor of flocculated matter in the water column was determined and found to be 7.31, higher than expected. Estimating food web protein contents using this factor, showed that a similar equivalent of protein as in shrimp, was accumulated in biofloc and periphyton combined, that remained unused in the system after shrimp harvest. Finding ways to use this protein (nitrogen) in the food web, would allow for reducing protein content in formulated diets. Lowering phosphorous input to the system with 50 %, had no effect on HUFA content of the food web and increased shrimp phosphorous retention from 16 to 34 %.

    Replacing up to 50 % of the feed input with carbohydrate and inorganic nitrogen that was directly accessible to the pond’s microbiota, did not result in differences in nutrient distribution and C:N:P ratios in food web compartments including shrimp in chapter 5. Natural food contribution to shrimp production increased significantly with reducing feeding level and increasing carbohydrate and inorganic nitrogen supplementation, but only if the system was within maximum carrying capacity. Computing mass balances of phosphorous revealed that following a > 30 % reduced system phosphorous input, flows of phosphorous in the food web changed. As a result, phosphorous from detritus flowed into periphyton in such rate that depletion would have occurred within one shrimp production cycle. This meant that when developing a nutritious pond diet where part of the feed is replaced with carbon and nitrogen fertilizer, phosphorous should be added too to prevent depletion, but reducing total phosphorous input up to 20 % is possible.

    Finally, chapter 6 synthesized the outcomes from this thesis by placing results into a broader context. The outcomes and recommendations following this thesis may contribute to the way we look at aquaculture in relation to sustainability, limited resources, climate change, nutrient flows, nutritional value of aquaculture products, and aquaculture ecology. With a still increasing world population there is need to change our current food production systems towards circular production systems. Climate change is going to affect aquaculture production and can be an extra challenge in order to further develop the nutritious pond concept, especially concerning de novo HUFA production in de pond. Nevertheless, the nutritious pond concept forms a crucial step towards a more sustainable aquaculture, independent of capture fisheries.

    Details of plastic ingestion and fibre contamination in North Sea fishes
    Kühn, Susanne ; Franeker, Jan A. van; O’donoghue, Anastasia M. ; Swiers, Ailynn ; Starkenburg, Marrit ; Werven, Bernike van; Foekema, Edwin ; Hermsen, Enya ; Egelkraut-holtus, Marion ; Lindeboom, Han - \ 2020
    Environmental Pollution 257 (2020). - ISSN 0269-7491
    This study combines published datasets with unpublished data on plastic ingestion in several North Sea fish species. The combined dataset of 4389 individuals from 15 species allows the analysis of spatial distribution and temporal variability of plastic uptake in fish. Airborne fibre contamination was observed to be the main contributor to fibres encountered in the samples. The number of fibres in samples was strongly related to the time needed to process a sample, not to the number of individual fishes in the sample. Accurate correction for secondary fibre contamination was not possible, but corrections required would be similar to fibre numbers observed in the samples. Consequently, all fibres were omitted from further analysis. The frequency of occurrence and the average number of plastics in fish is generally low (1.8% and 0.022 pieces per organism respectively), with only cod having a higher prevalence (12.3%). While latitude of catch locations influences plastic uptake in fish, no correlation with the distance to the coast was found. Slightly less plastics were ingested in winter, and a decrease in plastics ingested was observed between 2009 and 2018. These factors should be considered when fish species, catch location and time are discussed as indicators for plastic pollution in the European Marine Strategy Framework Directive. We recommend considering demersal cod and pelagic sprat as two species suitable for monitoring plastic ingestion in biota, both on the seafloor and in the water column.
    Challenges for Pond Aquaculture
    Verdegem, M.C.J. ; Bosma, R.H. ; Kabir, K.A. ; Hermsen, D. - \ 2019
    In: Book of abstracts of the 12th Asian Fisheries & Aquaculture Forum (AFAF). -
    Effect of bioflocs on seafood quality
    Hermsen, D. ; Declerck, S.A.J. ; Verdegem, M.C.J. - \ 2019
    In: Book of abstracts of the 12th Asian Fisheries & Aquaculture Forum (AFAF). - - p. 314 - 314.
    In a "nutritious pond" system, the incorporation of natural food elements into shrimp biomass may increase. This mesocosm study compared a Control diet containing fish oil and fishmeal, and a diet without these (low-H treatment). After 57 days, 12% of the feed input was metabolized into shrimp biomass, which did not differ between treatments. Control shrimp's, and total food web, HUFA content in the control tanks was twice as high than low-H. HUFA retention in the control was over ten-fold higher than Low-H tanks, pinpointing in situ de novo production of EPA, DHA and ARA. Among six food web compartments, the highest HUFA accumulation was observed in seston. Whether Low-H shrimp experienced a HUFA-deficient environment is not confirmed. Based on above, reducing fish oil and fishmeal in shrimp diets seems possible, but depends on the potential to canalize HUFA-containing algae in the seston into better accessible food web compartments.
    Effect of bioflocs on seafood quality
    Hermsen, Devi ; Waal, D.B. van de; Declerck, S.A.J. ; Verdegem, Marc - \ 2019
    In a "nutritious pond" system, the incorporation of natural food elements into shrimp biomass may increase. This mesocosm study compared a Control diet containing fish oil and fishmeal, and a diet without these (low-H treatment). After 57 days, 12% of the feed input was metabolized into shrimp biomass, which did not differ between treatments. Control shrimp's, and total food web, HUFA content in the control tanks was twice as high than low-H. HUFA retention in the control was over ten-fold higher than Low-H tanks, pinpointing in situ de novo production of EPA, DHA and ARA. Among six food web compartments, the highest HUFA accumulation was observed in seston. Whether Low-H shrimp experienced a HUFA-deficient environment is not confirmed. Based on above, reducing fish oil and fishmeal in shrimp diets seems possible, but depends on the potential to canalize HUFA-containing algae in the seston into better accessible food web compartments.
    Effects of eating with an augmented fork with vibrotactile feedback on eating rate and body weight: a randomized controlled trial
    Hermsen, Sander ; Mars, Monica ; Higgs, Suzanne ; Frost, Jeana H. ; Hermans, Roel C.J. - \ 2019
    International journal of behavioral nutrition and physical activity 16 (2019)1. - ISSN 1479-5868 - 1 p.
    Eating rate - Feedback - Randomized controlled trial - Sensory - Weight loss

    BACKGROUND: Eating rate is a basic determinant of appetite regulation: people who eat more slowly feel sated earlier and eat less. A high eating rate contributes to overeating and potentially to weight gain. Previous studies showed that an augmented fork that delivers real-time feedback on eating rate is a potentially effective intervention to decrease eating rate in naturalistic settings. This study assessed the impact of using the augmented fork during a 15-week period on eating rate and body weight. METHODS: In a parallel randomized controlled trial, 141 participants with overweight (age: 49.2 ± 12.3 y; BMI: 31.5 ± 4.48 kg/m2) were randomized to intervention groups (VFC, n = 51 or VFC+, n = 44) or control group (NFC, n = 46). First, we measured bite rate and success ratio on five consecutive days with the augmented fork without feedback (T1). The intervention groups (VFC, VFC+) then used the same fork, but now received vibrotactile feedback when they ate more than one bite per 10 s. Participants in VFC+ had additional access to a web portal with visual feedback. In the control group (NFC), participants ate with the fork without either feedback. The intervention period lasted four weeks, followed by a week of measurements only (T2) and another measurement week after eight weeks (T3). Body weight was assessed at T1, T2, and T3. RESULTS: Participants in VFC and VFC+ had a lower bite rate (p < .01) and higher success ratio (p < .0001) than those in NFC at T2. This effect persisted at T3. In both intervention groups participants lost more weight than those in the control group at T2 (p < .02), with no rebound at T3. CONCLUSIONS: The findings of this study indicate that an augmented fork with vibrotactile feedback is a viable tool to reduce eating rate in naturalistic settings. Further investigation may confirm that the augmented fork could support long-term weight loss strategies. TRIAL REGISTRATION: The research reported in this manuscript was registered on 4 November 2015 in the Netherlands Trial Register with number NL5432 ( https://www.trialregister.nl/trial/5432 ).

    Microplastics in freshwaters and drinking water: Critical review and assessment of data quality
    Koelmans, Albert A. ; Mohamed Nor, Nur Hazimah ; Hermsen, Enya ; Kooi, Merel ; Mintenig, Svenja M. ; France, Jennifer De - \ 2019
    Water Research 155 (2019). - ISSN 0043-1354 - p. 410 - 422.
    Drinking water - Human health - Microplastics - Surface water - Waste water
    Microplastics have recently been detected in drinking water as well as in drinking water sources. This presence has triggered discussions on possible implications for human health. However, there have been questions regarding the quality of these occurrence studies since there are no standard sampling, extraction and identification methods for microplastics. Accordingly, we assessed the quality of fifty studies researching microplastics in drinking water and in its major freshwater sources. This includes an assessment of microplastic occurrence data from river and lake water, groundwater, tap water and bottled drinking water. Studies of occurrence in wastewater were also reviewed. We review and propose best practices to sample, extract and detect microplastics and provide a quantitative quality assessment of studies reporting microplastic concentrations. Further, we summarize the findings related to microplastic concentrations, polymer types and particle shapes. Microplastics are frequently present in freshwaters and drinking water, and number concentrations spanned ten orders of magnitude (1 × 10−2to 108#/m3) across individual samples and water types. However, only four out of 50 studies received positive scores for all proposed quality criteria, implying there is a significant need to improve quality assurance of microplastic sampling and analysis in water samples. The order in globally detected polymers in these studies is PE ≈ PP > PS > PVC > PET, which probably reflects the global plastic demand and a higher tendency for PVC and PET to settle as a result of their higher densities. Fragments, fibres, film, foam and pellets were the most frequently reported shapes. We conclude that more high quality data is needed on the occurrence of microplastics in drinking water, to better understand potential exposure and to inform human health risk assessments.
    Quality criteria for the analysis of microplastic in biota samples: a critical review
    Hermsen, Enya ; Mintenig, Svenja M. ; Besseling, E. ; Koelmans, A.A. - \ 2018
    Environmental Science and Technology 52 (2018)18. - ISSN 0013-936X - p. 10230 - 10240.
    Data on ingestion of microplastics by marine biota are quintessential for monitoring and risk assessment of microplastics in the environment. Current studies, however, portray a wide spread in results on the occurrence of microplastic ingestion, highlighting a lack of comparability of results which might be attributed to a lack of standardisation of methods. We critically review and evaluate recent microplastic ingestion studies in aquatic biota, propose a quality assessment method for such studies, and apply the assessment method to the reviewed studies. The quality assessment method uses ten criteria: Sampling method and strategy, Sample size, Sample processing and storage, Laboratory preparation, Clean air conditions, Negative controls, Positive controls, Target component, Sample (pre-)treatment, and Polymer identification. The results of this quality assessment show a dire need for stricter quality assurance in microplastic ingestion studies. On average studies score 8.0 out of 20 points for ‘completeness of information’, and ‘zero’ for ‘reliability’. Alongside the assessment method, a standardised protocol for detecting microplastic in biota samples incorporating these criteria is provided.
    Detection of low numbers of microplastics in North Sea fish using strict quality assurance criteria
    Hermsen, E. ; Pompe, R. ; Besseling, E. ; Koelmans, A.A. - \ 2017
    Marine Pollution Bulletin 122 (2017)1-2. - ISSN 0025-326X - p. 253 - 258.
    We investigated 400 individual fish of four North Sea species: Atlantic Herring, Sprat, Common Dab, and Whiting on ingestion of > 20 μm microplastic. Strict quality assurance criteria were followed in order to control contamination during the study. Two plastic particles were found in only 1 (a Sprat) out of 400 individuals (0.25%, with a 95% confidence interval of 0.09–1.1%). The particles were identified to consist of polymethylmethacrylate (PMMA) through FTIR spectroscopy. No contamination occurred during the study, showing the method applied to be suitable for microplastic ingestion studies in biota. We discuss the low particle count for North Sea fish with those in other studies and suggest a relation between reported particle count and degree of quality assurance applied. Microplastic ingestion by fish may be less common than thought initially, with low incidence shown in this study, and other studies adhering to strict quality assurance criteria.
    The effect of real-time vibrotactile feedback delivered through an augmented fork on eating rate, satiation, and food intake
    Hermans, Roel C.J. ; Hermsen, Sander ; Robinson, Eric ; Higgs, Suzanne ; Mars, Monica ; Frost, Jeana H. - \ 2017
    Appetite 113 (2017). - ISSN 0195-6663 - p. 7 - 13.
    Digital technology - Eating rate - Food intake - Satiety - Vibrotactile feedback
    Eating rate is a basic determinant of appetite regulation, as people who eat more slowly feel sated earlier and eat less. Without assistance, eating rate is difficult to modify due to its automatic nature. In the current study, participants used an augmented fork that aimed to decelerate their rate of eating. A total of 114 participants were randomly assigned to the Feedback Condition (FC), in which they received vibrotactile feedback from their fork when eating too fast (i.e., taking more than one bite per 10 s), or a Non-Feedback Condition (NFC). Participants in the FC took fewer bites per minute than did those in the NFC. Participants in the FC also had a higher success ratio, indicating that they had significantly more bites outside the designated time interval of 10 s than did participants in the NFC. A slower eating rate, however, did not lead to a significant reduction in the amount of food consumed or level of satiation. These findings indicate that real-time vibrotactile feedback delivered through an augmented fork is capable of reducing eating rate, but there is no evidence from this study that this reduction in eating rate is translated into an increase in satiation or reduction in food consumption. Overall, this study shows that real-time vibrotactile feedback may be a viable tool in interventions that aim to reduce eating rate. The long-term effectiveness of this form of feedback on satiation and food consumption, however, awaits further investigation.
    Voedzame vijvers: nieuwe stappen in de ontwikkeling van duurzame vijverteelt
    Hermsen, D. - \ 2016
    Aquacultuur 31 (2016)4. - ISSN 1382-2764 - p. 34 - 38.
    Draaiboek Gedragsverandering : De psychologie van beinvloeding begrijpen en gebruiken
    Renes, R.J. ; Hermsen, Sander - \ 2016
    Business contact - ISBN 9789047009610 - 160
    Er wordt van alles uit de kast gehaald om het gedrag van mensen te veranderen: humor, celebrities, nudging en veel (te veel) informatie. Gedragsverandering is een actueel onderwerp: jongeren moeten minder drinken, autorijders voorzichtiger rijden, medewerkers stressvrijer werken. Bij de overheid, maar ook in het bedrijfsleven worden (reclame)campagnes, acties, (digitale) producten en online toepassingen ontworpen. Met wisselend succes.

    Wetenschappers Sander Hermsen en Reint Jan Renes laten in een levendige mix van concrete voorbeelden en de nieuwste inzichten zien hoe gedragsbeïnvloeding echt werkt. Wat maakt wel en wat maakt niet een effectieve campagne, product of dienst?

    Hun model, Persuasive by Design, is al in een groot aantal organisaties met succes toegepast. Dit boek is voor iedereen die wat te winnen heeft bij gezonder, veiliger, duurzamer of efficiënter gedrag.
    Evaluation of a Smart Fork to Decelerate Eating Rate
    Hermsen, Sander ; Frost, Jeana H. ; Robinson, Eric ; Higgs, Suzanne ; Mars, Monica ; Hermans, Roel C.J. - \ 2016
    Journal of the Academy of Nutrition and Dietetics 116 (2016)7. - ISSN 2212-2672 - p. 1066 - 1067.
    Overweight is associated with a range of negative health consequences, such as type 2 diabetes, cardiovascular disease, gastrointestinal disorders, and premature mortality.1 One means to combat overweight is through encouraging people to eat more slowly.2 People who eat quickly tend to consume more3, 4 and 5 and have a higher body mass index,6, 7, 8 and 9 whereas people who eat more slowly feel sated earlier and eat less.10, 11, 12 and 13. Unfortunately, eating rate is difficult to modify, because of its highly automatic nature.14 In clinical settings, researchers have had some success changing behavior by using devices that deliver feedback in real time.15, 16 and 17 However, existing technologies are either too cumbersome18 or not engaging enough19 for use in daily life contexts. Training people to eat more slowly in everyday eating contexts, therefore, requires creative and engaging solutions. This article presents a qualitative evaluation of the feasibility of a smart fork to decelerate eating rate in daily life contexts. Furthermore, we outline the planned research to test the efficacy of this device in both laboratory and community settings
    Aquaculture challenges in The Netherlands
    Hermsen, D. - \ 2015
    Molecular and functional characterization of the scavenger receptor CD36 in zebrafish and common carp
    Fink, I.R. ; Benard, E.L. ; Hermsen, G.J. ; Meijer, A.H. ; Forlenza, M. ; Wiegertjes, G. - \ 2015
    Molecular Immunology 63 (2015)2. - ISSN 0161-5890 - p. 381 - 393.
    toll-like receptors - salmon salmo-salar - cyprinus-carpio - density-lipoprotein - neutrophilic granulocytes - monoclonal-antibodies - accessory molecules - innate immunity - gene family - in-vivo
    CD36 is a scavenger receptor which has been studied closely in mammals where it is expressed by many different cell types and plays a role in highly diverse processes, both homeostatic and pathologic. It is among other things important in the innate immune system, in angiogenesis, and in clearance of apoptotic cells, and it is also involved in lipid metabolism and atherosclerosis. Recently, in the cephalochordate amphioxus a primitive CD36 family member was described, which was present before the divergence of CD36 from other scavenger receptor B family members, SCARB1 and SCARB2. Not much is known on the Cd36 molecule in teleost fish. We therefore studied Cd36 in both zebrafish and common carp, two closely related cyprinid fish species. Whereas a single cd36 gene is present in zebrafish, carp has two cd36 genes, and all show conserved synteny compared to mammalian CD36. The gene expression of carp cd36 is high in brain, ovary and testis but absent in immune organs. Although in mammals CD36 expression in erythrocytes, monocytes and macrophages is high, gene expression studies in leukocyte subtypes of adult carp and zebrafish larvae, including thrombocytes and macrophages provided no indication for any substantial expression of cd36 in immune cell types. Surprisingly, analysis of the cd36 promoter region does show the presence of several binding sites for transcription factors known to regulate immune responses. Overexpression of carp cd36 locates the receptor on the cell surface of mammalian cell lines consistent with the predicted topology of cyprinid Cd36 with a large extracellular domain, two transmembrane domains, and short cytoplasmic tails at both ends. Gene expression of cd36 is down-regulated during infection of zebrafish with Mycobacterium marinum, whereas knockdown of cd36 in zebrafish larvae led to higher bacterial burden upon such infection. We discuss the putative role for Cd36 in immune responses of fish in the context of other members of the scavenger receptor class B family.
    Developmental toxicity of thyroid-active compounds in a zebrafish embryotoxicity test
    Jomaa, B. ; Hermsen, S.A.B. ; Kessels, M.Y. ; Berg, J.H.J. van den; Peijenburg, A.C.M. ; Aarts, J.M.M.J.G. ; Piersma, A.H. ; Rietjens, I. - \ 2014
    Altex 31 (2014)3. - ISSN 0946-7785 - p. 303 - 317.
    Zebrafish embryos were exposed to concentration ranges of selected thyroid-active model compounds in order to assess the applicability of zebrafish-based developmental scoring systems within an alternative testing strategy to detect the developmental toxicity of thyroid-active compounds. Model compounds tested included triiodothyronine (T3), propylthiouracil (PTU), methimazole (MMI), sodium perchlorate (NaClO4) and amiodarone hydrochloride (AMI), selected to represent different modes of action affecting thyroid activity. Tested time windows included 48-120 hours post fertilization (hpf), 0-72 hpf and 0-120 hpf. All tested compounds resulted in developmental changes, with T3 being the most potent. The developmental parameters affected included reflective iridophores, beat and glide swimming, inflated swim bladders, as well as resorbed yolk sacs. These effects are only evident by 120 hpf and therefore an existing General Morphology Score (GMS) system was extended to create a General Developmental Score (GDS) that extends beyond the 72 hpf scoring limit of GMS and includes additional parameters that are affected by exposure to model thyroid-active compounds. Moreover, the GDS is cumulative as it includes not only the scoring of developmental morphologies but also integrates developmental dysmorphologies. Exposures from 48-120 hpf did not provide additional information to exposures from 0-120 hpf. The results indicate that the zebrafish GDS can detect the developmental toxicity of thyroid toxicants and may be of use in an integrated testing strategy to reduce, refine and, in certain cases, replace animal testing.
    Adrenergic regulation of the innate immune response in common carp (Cyprinus carpio L.)
    Chadzinska, M.K. ; Tertil, E. ; Kepka, M. ; Hermsen, G.J. ; Scheer, M.H. ; Verburg-van Kemenade, B.M.L. - \ 2012
    Developmental and Comparative Immunology 36 (2012)2. - ISSN 0145-305X - p. 306 - 316.
    trout oncorhynchus-mykiss - necrosis-factor-alpha - rainbow-trout - beta-adrenoceptors - in-vitro - beta(2)-adrenergic receptor - neutrophilic granulocytes - interleukin-10 production - corticosteroid receptors - catecholamine secretion
    Catecholamines exert their physiological actions through a and ß adrenergic receptors (ARs). As ARs are not exclusively expressed on neuroendocrine cells, but also on leukocytes, they may facilitate neuroendocrine modulation of immune responses. We sequenced the ß2a-AR in common carp, and studied its expression profile and involvement in the regulation of teleost innate immune responses. ß2a-AR messenger RNA was found to be constitutively expressed in brain areas, especially in the preoptic nucleus (NPO, homologous to the mammalian hypothalamus), and in immune organs. During the active phase of an in vivo inflammatory response, induced by i.p. zymosan treatment, ß2a-AR gene expression was up-regulated in the peritoneal leukocytes. Additionally, adrenaline in vitro reduced the synthesis of oxygen radical species and nitric oxide, while it enhanced arginase activity in fish phagocytes. Furthermore, in vitro adrenaline administration inhibited expression of pro-inflammatory cytokines, chemokines and their receptors. It is therefore hypothesized that adrenaline will down-regulate phagocyte skewing toward classical/innate polarization.
    Hamsters (Cricetus cricetus) and Camera – Use of a camera for collecting biological data about number of litters and the gain of weight of young in the first two months.
    Muskens, G.J.D.M. ; Out, M. ; Kats, R.J.M. van; Hermsen, A.M. ; Haye, M.J.J. la; Kuiters, A.T. - \ 2011
    In: Proceedings of the 16th and 17th Meeting of the International Hamster Workgroup; Ranis, Germany (2009), Gödollo, Hungary (2010), 25-27 October 2010. - - p. 117 - 120.
    Gedragsstudie Siberische Husky. Deel 1: De Enquete
    Hermsen, D. ; Koene, P. - \ 2011
    MusH 6 (2011)30. - p. 31 - 41.
    Gedragsstudie Siberische Husky. Deel 2 : Het gedrag.
    Hermsen, D. ; Koene, P. - \ 2011
    MusH 6 (2011)31. - p. 33 - 39.
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