Records 21 - 40 / 269
|Growth rate of broiler chickens is influenced by early life feeding strategy
Hollemans, M.S. ; Lammers, A. ; Vries, S. de - \ 2018
In: The XVth European Poultry Conference (EPC). - Zagreb, Croatia : - ISBN 9789082915709 - p. 579 - 579.
delayed nutrition - early nutrition - Intestinal permeability - compensatory growth
After hatching in conventional systems, broiler chickens have a delay to nutrition thatcan last for 72h, depending on length of the hatch window, internal hatchery proceduresand transport duration. Previous research on early life feeding strategies has shownnegative effects on bodyweight (BW) gain after delayed nutrition (DN), compared withearly nutrition (EN). However, it is not known whether DN chickens can (partially)compensate for their lower BW between hatch and slaughter. In this study, we tested thehypothesis that DN chickens have an increased growth rate, as a result of compensatorygrowth. Data from 3 independent experiments were used. In these studies, broilerswere subjected to either EN or DN with different durations of DN (38 to 72 h) and daysto slaughter (14 to 35 d). In all experiments, DN groups had lower BW compared withEN which was sustained until slaughter. Relative differences in BW, however, decreasedfrom 114 to 176% post placement to 102 – 112 % at slaughter (35 d). Growth curves of DNand EN chickens were analysed to study whether compensatory growth could explain thedifferences in BW between EN and DN. Absolute average daily gain (aADG) was higher inEN chickens from start until slaughter. To analyse the growth curve independent of BW,relative ADG (rADG) between two ages was calculated as follows:Differences in rADG between DN and EN chickens were greater in the first 14 d (DN:63%, EN: 47%; P < 0.001), but smaller in the remaining grow-out period (14 – 28 d:DN: 18%, EN: 16%; 28 – 35 d: DN: 8%, EN: 7%; both P <0 .001). Based on these results,it seems that DN broilers compensate for their lag in BW during the first 14 d postplacement. As differences in absolute BW were still present at 35 d, the increase in rADGseems insufficient to catch up with EN broilers. EN chickens have higher aADG untilslaughter, however, rADG is lower, showing that growth rate is influenced by feedingstrategy. Previous literature describes interactions between compensatory growth andnutrient composition of diets on nitrogen and fat retention. This may give reason forfuture work to evaluate effects of early life feeding strategy on carcass traits.
|Body weight is affected by early life feeding strategy and hatch moment in broiler chickens
Hollemans, M.S. ; Noorloos, Marit ; Vries, S. de; Lammers, A. - \ 2018
In: The XVth European Poultry Conference (EPC). - Zagreb, Croatia : - ISBN 9789082915709 - p. 259 - 259.
delayed nutrition - early nutrition - Intestinal permeability - compensatory growth
After hatching in conventional systems, broiler chickens have a delay to nutrition that can last for 72h, depending on length of the hatch window, internal hatchery procedures and transport duration. Previous research on early life feeding strategies has shown negative effects on bodyweight (BW) gain after delayed nutrition (DN), compared with early nutrition (EN). However, it is not known whether DN chickens can (partially)compensate for their lower BW between hatch and slaughter. In this study, we tested the hypothesis that DN chickens have an increased growth rate, as a result of compensatory growth. Data from 3 independent experiments were used. In these studies, broilers were subjected to either EN or DN with different durations of DN (38 to 72 h) and days to slaughter (14 to 35 d). In all experiments, DN groups had lower BW compared withEN which was sustained until slaughter. Relative differences in BW, however, decreased from 114 to 176% post placement to 102 – 112 % at slaughter (35 d). Growth curves of DN and EN chickens were analysed to study whether compensatory growth could explain the differences in BW between EN and DN. Absolute average daily gain (aADG) was higher in EN chickens from start until slaughter. To analyse the growth curve independent of BW, relative ADG (rADG) between two ages was calculated as follows: Differences in rADG between DN and EN chickens were greater in the first 14 d (DN:63%, EN: 47%; P < 0.001), but smaller in the remaining grow-out period (14 – 28 d:DN: 18%, EN: 16%; 28 – 35 d: DN: 8%, EN: 7%; both P <0 .001). Based on these results,it seems that DN broilers compensate for their lag in BW during the first 14 d postplacement. As differences in absolute BW were still present at 35 d, the increase in rADG seems insufficient to catch up with EN broilers. EN chickens have higher aADG until slaughter, however, rADG is lower, showing that growth rate is influenced by feeding strategy. Previous literature describes interactions between compensatory growth and nutrient composition of diets on nitrogen and fat retention. This may give reason for future work to evaluate effects of early life feeding strategy on carcass traits.
Learning by Creating a MOOC
Frederiks, Gwenda ; Mirck, Sanne ; Stalpers, Serge ; Lammers, Sietske - \ 2018
In: Proceedings of 2018 Learning With MOOCS, LWMOOCS 2018. - Institute of Electrical and Electronics Engineers Inc. - ISBN 9781538665336 - p. 127 - 130.
MOOC - OER - open pedagogy - skills development - student-created MOOC
Massive Open Online Courses (MOOCs) can be a platform for campus students to publish co-created educational material. Involving students in the creation of a MOOC has the potential to lead to a more learner-centered MOOC while also providing students with the opportunity to gain skills. This exploratory case study evaluates that potential. We analyze the learning gains of the students, the MOOC they created (the product), and our own support during the development process. Analysis shows that the MOOC had a similar quality to our other MOOCs. Videos and assignments were more creative than usual, but were not created with a much more learner-centered focus. The students gained valuable skills while making the MOOC, such as leadership skills and video presenting skills. The support from university staff was seen as very valuable, but could have been expanded to truly elevate the quality of the content. We end this paper with some practical recommendations for other teams wishing to help students create a MOOC.
|Exploring practice based theories for health promotion among families with low socio-economic status
Hogeling, L. ; Crijns-Lammers, Christianne ; Vaandrager, L. ; Koelen, M.A. - \ 2018
Ant-like Traits in Wingless Parasitoids Repel Attack from Wolf Spiders
Harvey, Jeffrey A. ; Visser, Bertanne ; Lammers, Marl ; Marien, Janine ; Gershenzon, Jonathan ; Ode, Paul J. ; Heinen, Robin ; Gols, Rieta ; Ellers, Jacintha - \ 2018
Journal of Chemical Ecology 44 (2018)10. - ISSN 0098-0331 - p. 894 - 904.
Batesian mimicry; Müllerian mimicry - Chemical defense - Formica - Gelis - Hymenoptera - Lasius - Predation
A recent study showed that a wingless parasitoid, Gelis agilis, exhibits a suite of ant-like traits that repels attack from wolf spiders. When agitated, G. agilis secreted 6-methyl-5-hepten-2-one (sulcatone), which a small number of ant species produce as an alarm/panic pheromone. Here, we tested four Gelis parasitoid species, occurring in the same food chain and microhabitats, for the presence of sulcatone and conducted two-species choice bioassays with wolf spiders to determine their degree of susceptibility to attack. All four Gelis species, including both winged and wingless species, produced sulcatone, whereas a closely related species, Acrolyta nens, and the more distantly related Cotesia glomerata, did not. In two-choice bioassays, spiders overwhelmingly rejected the wingless Gelis species, preferring A. nens and C. glomerata. However, spiders exhibited no preference for either A. nens or G. areator, both of which are winged. Wingless gelines exhibited several ant-like traits, perhaps accounting for the reluctance of spiders to attack them. On the other hand, despite producing sulcatone, the winged G. areator more closely resembles other winged cryptines like A. nens, making it harder for spiders to distinguish between these two species. C. glomerata was also preferred by spiders over A. nens, suggesting that other non-sulcatone producing cryptines nevertheless possess traits that make them less attractive as prey. Phylogenetic reconstruction of the Cryptinae reveals that G. hortensis and G. proximus are ‘sister’species, with G. agilis, and G.areator in particular evolving along more distant trajectories. We discuss the possibility that wingless Gelis species have evolved a suite of ant-like traits as a form, of mimicry to repel predators on the ground.
Feather pecking genotype and phenotype affect behavioural responses of laying hens
Eijk, Jerine A.J. van der; Lammers, Aart ; Li, Peiyun ; Kjaer, Joergen B. ; Rodenburg, T.B. - \ 2018
Applied Animal Behaviour Science 205 (2018). - ISSN 0168-1591 - p. 141 - 150.
Activity - Coping style - Fearfulness - Feather pecking - Genotype - Phenotype
Feather pecking (FP) is a major welfare and economic issue in the egg production industry. Behavioural characteristics, such as fearfulness, have been related to FP. However, it is unknown how divergent selection on FP affects fearfulness in comparison to no selection on FP. Therefore, we compared responses of birds selected on low (LFP) and high feather pecking (HFP) with birds from an unselected control line (CON) to several behavioural tests (i.e. novel object (NO), novel environment (NE), open field (OF) and tonic immobility (TI)) at young and adult ages. Furthermore, the relation between actual FP behaviour (i.e. FP phenotypes) and fearfulness is not well understood. Therefore, we compared responses of birds with differing FP phenotypes. Feather pecking phenotypes of individual birds were identified via FP observations at several ages. The number of severe feather pecks given and received was used to categorize birds as feather peckers, feather pecker-victims, victims or neutrals. Here we show that HFP birds repeatedly had more active responses (i.e. they approached a NO sooner, vocalized sooner and more, showed more flight attempts and had shorter TI durations), which could indicate lower fearfulness, compared to CON and LFP birds at both young and adult ages. Within the HFP line, feather peckers had more active responses (i.e. they tended to show more flight attempts compared to victims and tended to walk more compared to neutrals), suggesting lower fearfulness, compared to victims and neutrals. Thus, in this study high FP seems to be related to low fearfulness, which is opposite to what previously has been found in other experimental and commercial lines. This stresses the need for further research into the genetic and phenotypic correlations between FP and fearfulness in various populations of chickens, especially in commercial lines. Findings from experimental lines should be used with caution when developing control and/or prevention methods that are to be applied in commercial settings. Furthermore, activity and/or coping style might overrule fearfulness within the HFP line, as HFP birds and feather peckers within the HFP line had more active responses. This might indicate a complex interplay between fearfulness, activity and coping style that could play a role in the development of FP.
Effects of early feeding and dietary interventions on development of lymphoid organs and immune competence in neonatal chickens : A review
Taha-Abdelaziz, Khaled ; Hodgins, Douglas C. ; Lammers, Aart ; Alkie, Tamiru Negash ; Sharif, Shayan - \ 2018
Veterinary Immunology and Immunopathology 201 (2018). - ISSN 0165-2427 - p. 1 - 11.
Antimicrobial peptides - Chicken - Dietary supplementation - Early feeding - Feed additives - Heat stress - Immune system - In ovo feeding - Lymphoid organs - Nanoparticles - Phytobiotics - Prebiotics - Probiotics - TLR ligands
With the ongoing intensification of the poultry industry and the continuous need to control pathogens, there is a critical need to extend our understanding of the avian immune system and the role of nutritional interventions on development of immune competence in neonatal chicks. In this review, we will focus on the ontogeny of the lymphoid organs during embryonic life and the first 2 weeks post-hatch, and how early feeding practices improve heath and modulate the development and function of the immune system in young chicks. The evidence for the positive impact of the nutrition of breeder hens on embryonic development and on the survival and immunity of their chicks will also be outlined. Additionally, we will discuss the vital role of supplemental feeding either in ovo or immediately post-hatch in chick health and immunity and the importance of these approaches in ameliorating immune system functions of heat-stressed chicks. To conclude, we provide some perspectives on a number of key issues, concerning the mechanisms of nutritional modulation of immunity, that need to be addressed. A thorough investigation of these mechanisms may assist in the formulation of diets to improve the immunity and general health status.
Effects of early nutrition and transport of 1-day-old chickens on production performance and fear response
Hollemans, M.S. ; Vries, S. de; Lammers, A. ; Clouard, C.M. - \ 2018
Poultry Science 97 (2018)7. - ISSN 0032-5791 - p. 2534 - 2542.
broiler - chicken - early nutrition - transport - behavior - production performance
The importance of optimal early life conditions of broilers to sustain efficient and healthy production of broiler meat is increasingly recognized. Therefore, novel husbandry systems are developed, in which immediate provision of nutrition post hatch is combined with on-farm hatching. In these novel systems, 1-day-old-chick handling and transport are minimized. To study whether early nutrition and reduced transport are beneficial for broiler performance and behavior, the effects of early or delayed nutrition and post-hatch handling and transport were tested from hatch until 35 d of age, in a 2 × 2 factorial arrangement. In total, 960 eggs were hatched in 36 floor pens. After hatch, chicks were given immediate access to water and feed (early nutrition) or after 54 h (delayed nutrition). Eighteen hours after hatch, chicks remained in their pens (non-transported control), or were subjected to short-term handling and transport to simulate conventional procedures. Subsequently, chicks returned to their pens. Compared with delayed-fed chickens, early-fed chickens had greater body weight up to 21 d of age, but not at slaughter (35 d of age). No effects of transport or its interaction with moment of first nutrition were found on performance. At 3 d post hatch, transported, early-fed chicks had a greater latency to stand up in a tonic immobility test than transported, delayed-fed chicks, but only in chicks that were transported. At 30 d post hatch, however, latency was greater in transported, delayed-fed chickens than in transported, early-fed chicks. This may indicate long-term deleterious effects of delayed nutrition on fear response in transported chickens. It is concluded that early nutrition has mainly beneficial effects on performance during the first 2 wk post hatch, but these beneficial effects are less evident in later life. The combination of transport and early nutrition may influence the chicken's strategies to cope with stressful events in early and later life.
|Early life feeding strategy and hatch moment affects early life body weight development
Hollemans, M.S. ; Noorloos, Marit ; Vries, S. de; Lammers, A. - \ 2018
In: Abstract of the WIAS Science Day 2018. - - p. 28 - 28.
Antigen-dependent effects of divergent selective breeding based on natural antibodies on specific humoral immune responses in chickens
Berghof, T.V.L. ; Arts, J.A.J. ; Bovenhuis, H. ; Lammers, A. ; Poel, J.J. van der; Parmentier, H.K. - \ 2018
Vaccine 36 (2018)11. - ISSN 0264-410X - p. 1444 - 1452.
Breeding - Chicken - General disease resistance - Keyhole limpet hemocyanin (KLH) - Natural antibody - Specific antibody
NAb are defined as antigen binding antibodies present without a known previous exposure to this antigen. NAb are suggested to enhance specific antibody (SpAb) responses, but consequences of different NAb levels on immunization are largely unknown. Layer chickens were divergently selected and bred for keyhole limpet hemocyanin (KLH)-binding NAb titers, resulting in a High line and a Low line. In this study, we investigated: (1) the relation of NAb levels with SpAb titers; and (2) the effect of immunization on NAb titers. The 50 highest females of the High line and the 50 lowest females of the Low line of generation 2 were intramuscularly immunized at 33 weeks of age with 1 mL phosphate buffered saline (PBS) containing one of four treatments: (1) negative control (no antigen), (2) 500 μg KLH, (3) 100 μg avian tuberculin purified protein derivative of Mycobacterium avium (PPD), or (4) 250 μg human serum albumin (HuSA). IgM and IgG titers of NAb and SpAb in plasma were determined prior to immunization and weekly for 5 weeks post immunization by indirect ELISA. In addition, antibody affinity was investigated. No differences in SpAb and NAb response against KLH and PPD were observed as a consequence of different NAb titers, but increased and prolonged SpAb and NAb titer responses against HuSA were observed for the High line compared to the Low line. Different natural antibody titers did not impair SpAb dynamics and SpAb affinity. NAb titers were not, or for only short-term, affected by immunization. We show here that NAb may enhance SpAb responses, but that this effect is antigen-dependent. We hypothesize that NAb play a role in general disease resistance through enhancement of the humoral adaptive immune response.
|Effect of butyrate concentration in the GIT on innate and adaptive immune responses of broilers
Moquet, P.C.A. ; Konnert, G.D.P. ; Lammers, A. ; Onrust, L. ; Kwakkel, R.P. - \ 2017
|Early nutrition strategy and transport play a role in the development of fear response and production performance
Hollemans, M.S. ; Vries, S. de; Lammers, A. ; Clouard, C.M. - \ 2017
- p. 55 - 56.
Behavioural and physiological characterisation of laying hen lines divergently selected on feather pecking
Eijk, J.A.J. van der; Lammers, A. ; Rodenburg, T.B. - \ 2017
In: Xth European Symposium on Poultry Welfare, 19-22 June 2017, Ploufragan - France. - World's Poultry Science Association (WPSA) - p. 60 - 60.
broiler breeders - nesting behaviour - genetics - nest design - housing - climate - laying hens - feather pecking - fearfulness - coping style - stress - imune system
Broilers have been selected for growth related characteristics, which are negatively correlated to reproductive traits. This genetic background creates challenges in broiler breeders, as the hens do not make optimal use of the nests provided. This project aims to investigate what factors determine nesting behaviour, i.e. where a broiler breeder hen prefers to lay her eggs. Factors such as genetic background, social interactions, physical characteristics of the nest and climate might interfere with the natural nesting behaviour of the hen. Also fundamental trade-offs between different motivations, such as hunger, comfort and safety, might influence nesting behaviour. Behaviour and use of space will be measured in experimental set-ups in order to gain insight in the importance of different system components. This knowledge will be used to optimise housing conditions and develop strategies that stimulate the hen to lay her egg in the nest. The performance of this improved system will be tested in field experiments to investigate the transferability of results from experimental to field conditions.
Feather pecking: is it in the way hens cope with stress?
Eijk, J.A.J. van der; Rodenburg, T.B. ; Lammers, A. - \ 2017
In: Proceedings of the 51st Congress of the International Society for Applied Ethology (ISAE), 7-10 August 2017, Aarhus, Denmark. - Wageningen : Wageningen Academic Publishers - ISBN 9789086863112 - p. 139 - 139.
animal welfare - animal behaviour
|Effects of early nutrition and transport of one-day-old chickens on production performance and behavior
Hollemans, M.S. ; Vries, S. de; Lammers, A. ; Clouard, C.M. - \ 2017
In: Abstract of the WIAS Science Day 2017: Beyond Sustainability. - - p. 9 - 9.
Nutrition of pigs kept under low and high sanitary conditions : effects on animo acid and energy metabolism and damaging behaviour
Meer, Yvonne van der - \ 2017
Wageningen University. Promotor(en): W.J.J. Gerrits, co-promotor(en): A.J.M. Jansman; A. Lammers. - Wageningen : Wageningen University - ISBN 9789463431972 - 181
pigs - feeds - pig feeding - animal nutrition - amino acid metabolism - animal health - energy metabolism - abnormal behaviour - behaviour disorders - immune system - nutrition physiology - varkens - voer - varkensvoeding - diervoeding - aminozuurmetabolisme - diergezondheid - energiemetabolisme - abnormaal gedrag - gedragsstoornissen - immuunsysteem - voedingsfysiologie
It is economically and environmentally important to match the nutrient supply to the nutrient requirements in pig production. Until now, the effects of different sanitary conditions on energy and nutrient requirements are not implemented in recommendations for nutrient composition of pig diets. The current nutrient requirement data are based on studies with pigs in experimental settings, which can be regarded as rather optimal. Changes in nutrient requirements caused by differences in sanitary conditions are poorly documented. As in the pig production sector farm conditions are variable it is of major importance to determine the effects of low sanitary conditions (LSC) on requirements for amino acids and energy in growing pigs. Pigs under LSC have an increased risk of clinical and subclinical infections, resulting in a chronic stimulation of their immune system. Immune system stimulation is known to influence energy and amino acid metabolism. However, most studies in pigs evaluating the relationship between immune system stimulation and nutrient requirements often use specific experimental challenge models. Whereas such models have the obvious advantage of reproducibility and allow mechanistic insight in the effects of stimulating specific parts of the immune system, these models often induce clinical illness, rather than subclinical infections. Results obtained with such models may therefore be difficult to translate to practical situations. Therefore the objective of the present thesis was to study the effect of low and high sanitary conditions (HSC) on amino acids and energy metabolism in pigs. Also interactions between the immune system, nutrient metabolism and damaging behaviour of pigs were considered in this thesis.
The experiment described in Chapter 2 was designed to study the effect of different dietary crude protein levels and extra amino acid supplementation on the growth performance of pigs kept under different sanitary conditions. In a 2×2×2 factorial arrangement, 68 groups of 9 pigs were allocated to either LSC or HSC, and were offered ad libitum access to two different diets, a normal crude protein concentration diet or a low crude protein concentration diet, each having either a basal dietary amino acid profile or supplemented dietary amino acid profile containing 20% more methionine, threonine, and tryptophan compared with the basal profile. The pigs were followed from 10 weeks of age until slaughter. Haptoglobin concentrations in serum and IgG antibody titers against keyhole limpet heamocyanin, collected in the starter, grower, and finisher phases, and pleuritis scores at slaughter were greater for LSC pigs compared with HSC pigs, illustrating that sanitary conditions affected health conditions. The average daily gain and gain to feed ratio were greater for HSC pigs compared with LSC pigs. A 20% increase in dietary supplementation of methionine, threonine, and tryptophan relative to lysine increased gain to feed ratio more in LSC than in HSC pigs. The results therefore illustrated that dietary requirements for methionine. threonine, and tryptophan were greater for LSC compared with HSC pigs.
In Chapter 3 the damaging behaviour of 576 pigs from the experiment in Chapter 2 was evaluated. At 15, 18, and 24 weeks of age, prevalence of tail and ear damage, and of tail and ear wounds was scored. At 20 and 23 weeks of age, frequencies of biting behaviour and aggression were scored by behaviour sampling. The prevalence of ear damage during the finisher phase and the frequency of ear biting were increased in LSC compared with HSC pigs. The frequency of ear biting was increased in low protein fed pigs compared with normal protein fed pigs. The supplemented AA profile reduced ear biting only in LSC pigs. The prevalence of tail wounds was lower for pigs in LSC than for pigs in HSC in the grower phase. Regardless of dietary amino acid profile or sanitary status, pigs fed low protein diets showed more ear biting, tail biting, belly nosing, other oral manipulation directed at pen mates, and aggression than pigs fed normal protein diets, with no effect on ear or tail damage. In conclusion, both LSC and a reduction of dietary protein increased the occurrence of damaging behaviours in pigs and therefore may negatively impact pig welfare.
The experiment of Chapter 4 was designed to quantify the difference in energy requirements for maintenance, and in incremental efficiencies for deposition of dietary energy and protein in the body of clinically healthy pigs kept under LSC or HSC, fed a basal diet either or not supplemented with additional methionine, threonine and tryptophan.
In a 2 × 2 factorial arrangement, 24 groups of 6 pigs each were allocated to either a LSC or HSC, and were offered two different diets having either a basal or a dietary amino acid profile supplemented with methionine, threonine, and tryptophan. For each group of pigs, complete energy and nitrogen balances were determined during two consecutive weeks, during which feed was available ad libitum or at 70% of ad libitum. Fasting heat production was determined over a 25 h period of fasting after a period of restricted feeding. Low sanitary conditions increased fasting heat production from 696 to 750 kJ/(kg BW0.6 . d), regardless of the dietary amino acid supplementation. The incremental efficiency of ingested nitrogen for retention in the body was reduced in LSC pigs from 73 to 53%, but incremental efficiencies of digestible energy intake for fat deposition in the body were unaffected by the experimental treatments. These findings showed that the effects of continuous immune stimulation by introducing LSC, was affecting energy and nutrient efficiencies of pigs both at maintenance level and at a feeding level close to ad libitum intake.
In Chapter 5 diurnal patterns for heat production, respiratory quotient, and carbohydrate and fat oxidation of the pigs studied in the experiment of Chapter 4 were evaluated to get more insight in the mechanisms behind the effects found in Chapter 4. The LSC pigs had reduced activity compared with HSC and a higher resting metabolic rate during the period of restricted feeding, especially during the light parts of the day. Therefore the diurnal energy expenditure pattern of LSC and HSC pigs can be considered as different. Fat and carbohydrate oxidation patterns were not different for LSC and HSC pigs, indicating that protein and fat deposition during the day was similar for LSC and HSC pigs.
Overall, the results of this thesis indicate that both energy and AA requirements are greater in LSC pigs compared with HSC pigs. It is questionable, however, whether it is nutrient and cost effective and biologically possible to satisfy these increased nutrient requirements in LSC pigs, as the incremental efficiency of N for retained protein is low, and ADFI is reduced for LSC pigs compared with HSC pigs. The present thesis demonstrates that care should be taken in reducing dietary protein concentrations to improve protein efficiency in pigs, as it incurs a risk to increased damaging behaviours, particularly when pigs are kept under LSC.
High-throughput sequencing of African chikanda cake highlights conservation challenges in orchids
Veldman, Sarina ; Gravendeel, Barbara ; Otieno, Joseph N. ; Lammers, Youri ; Duijm, Elza ; Nieman, Aline ; Bytebier, Benny ; Ngugi, Grace ; Martos, Florent ; Andel, Tinde R. van; Boer, Hugo J. de - \ 2017
Biodiversity and Conservation 26 (2017)9. - ISSN 0960-3115 - p. 2029 - 2046.
CITES - Disa - Ethnobotany - Habenaria - Ion-Torrent PGM - Satyrium - Wildlife forensics
Chikanda is a traditional dish made with wild-harvested ground orchid tubers belonging to three orchidioid genera, Disa, Satyrium and Habenaria, all of which are CITES appendix II-listed. Identification of collected orchid tubers is very difficult and documentation of constituent species in prepared chikanda has hitherto been impossible. Here amplicon metabarcoding was used in samples of six prepared chikanda cakes to study genetic sequence diversity and species diversity in this product. Molecular operational taxonomic unit identification using similarity-matching reveals that species of all three genera were present in the chikanda samples studied. Disa was present in all of the samples, Satyrium in five out of six and Habenaria in one of the samples, as well as a number of other plants. The fact that each sample contained orchids and the presence of a wide variety of species from all genera in this traditional dish raise serious concerns about the sustainability of this trade and the future of wild orchid populations in the main harvest areas. This proof-of-concept study shows that Ion-Torrent PGM is a cost-effective scalable platform for metabarcoding using the relatively long nrITS1 and nrITS2 regions. Furthermore, nrITS metabarcoding can be successfully used for the detection of specific ingredients in a highly-processed food product at genus level, and this makes it a useful tool in the detection of possible conservation issues arising from commercialized trade or processed plant products.
Splicing-related genes are alternatively spliced upon changes in ambient temperatures in plants
Verhage, D.S.L. ; Severing, Edouard ; Bucher, J. ; Lammers, M. ; Busscher-Lange, J. ; Bonnema, A.B. ; Rodenburg, Nicole ; Proveniers, Marcel C.G. ; Angenent, G.C. ; Immink, G.H. - \ 2017
PLoS ONE 12 (2017)3. - ISSN 1932-6203
Plants adjust their development and architecture to small variations in ambient temperature. In a time in which temperatures are rising world-wide, the mechanism by which plants are able to sense temperature fluctuations and adapt to it, is becoming of special interest. By performing RNA-sequencing on two Arabidopsis accession and one Brassica species exposed to temperature alterations, we showed that alternative splicing is an important
mechanism in ambient temperature sensing and adaptation. We found that amongst the differentially alternatively spliced genes, splicing related genes are enriched, suggesting that the splicing machinery itself is targeted for alternative splicing when temperature changes. Moreover, we showed that many different components of the splicing machinery are targeted for ambient temperature regulated alternative splicing. Mutant analysis of a splicing related gene that was differentially spliced in two of the genotypes showed an altered flowering
time response to different temperatures. We propose a two-step mechanism where temperature directly influences alternative splicing of the splicing machinery genes, followed by a second step where the altered splicing machinery affects splicing of downstream genes involved in the adaptation to altered temperatures.
Notitie ‘Verdeling van beschikbare N uit drijfmest over het seizoen op grasland’
Schroder, J.J. ; Curth-van Middelkoop, J.C. - \ 2016
Wageningen UR Livestock Research, Commissie Bemesting Grasland en Voedergewassen - 8
Ongeveer de helft van de stikstof (N) in rundveedrijfmest is organisch gebonden. Voor varkensdrijfmest is dat ongeveer een derde (Den Boer et al., 2012). Deze organisch gebonden N moet worden afgebroken (‘mineraliseren’) om door gewassen te kunnen worden opgenomen. Volledige afbraak kan tientallen jaren kosten. Bij een langdurig voortgezet gebruik van eenzelfde hoeveelheid organische mest-N komen de jaarlijkse aanvoer en de geaccumuleerde ‘staartjes’ afbraak met elkaar in evenwicht. Omstandig bewijs hiervoor kan gevonden worden in het feit dat de hoeveelheden organische stof in Nederlandse landbouwbodems niet lijken te stijgen (Reijneveld et al., 2009). Sluijsmans & Kolenbrander (1976) namen op basis van laboratoriumproeven met verdund zwavelzuur aan dat de helft van de organisch gebonden N in rundveedrijfmest al gedurende het eerste jaar na het moment van toediening mineraliseert (‘Ne’) en de andere helft (‘Nr’) in de (vele) jaren daarna. Overeenkomstige waarden voor varkensdrijfmest bedragen tweederde (‘Ne’) en één derde (‘Nr’). Op zichzelf is het begrijpelijk dat de mest van een met ruwvoer gevoede meermagige lastiger afbreekbaar is dan die van een éénmagige. Op basis van deze uitgangspunten berekende Lammers (1983) de eerstejaars N-werking van, onder meer, rundveedrijfmest en varkensdrijfmest.
Selection for or against feather pecking: what are the consequences?
Eijk, J.A.J. van der; Lammers, A. ; Kemp, B. ; Naguib, M. ; Rodenburg, T.B. - \ 2016
In: 16th International Conference on Production Diseases in Farm Animals. - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086862856 - p. 176 - 176.