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.

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    A method to assess social sustainability of capture fisheries: An application to a Norwegian trawler
    Veldhuizen, L.J.L. ; Berentsen, P.B.M. ; Bokkers, E.A.M. ; Boer, I.J.M. de - \ 2015
    Environmental Impact Assessment Review 53 (2015). - ISSN 0195-9255 - p. 31 - 39.
    time-temperature integrators - different quality parameters - production systems - egg-production - swot analysis - indicators - fish - farm - appraisal - rapfish
    Social sustainability assessment of capture fisheries is, both in terms of method development and measurement, not well developed. The objective of this study, therefore, was to develop a method consisting of indicators and rubrics (i.e. categories that articulate levels of performance) to assess social sustainability of capture fisheries. This method was applied to a Norwegian trawler that targets cod and haddock in the northeast Atlantic. Based on previous research, 13 social sustainability issues were selected. To measure the state of these issues, 17 process and outcome indicators were determined. To interpret indicator values, rubrics were developed for each indicator, using standards set by international conventions or data retrieved from national statistics, industry agreements or scientific publications that explore rubric scales. The indicators and rubrics were subsequently used in a social sustainability assessment of a Norwegian trawler. This assessment indicated that overall, social sustainability of this trawler is relatively high, with high rubric scores, for example, for worker safety, provisions aboard for the crew and companies' salary levels. The assessment also indicated that the trawler could improve on healthy working environment, product freshness and fish welfare during capture. This application demonstrated that our method provides insight into social sustainability at the level of the vessel and can be used to identify potential room for improvement. This method is also promising for social sustainability assessment of other capture fisheries.
    Effects of growth patterns and dietary protein levels during rearing of broiler breeders on fertility, hatchability, embryonic mortality, and offspring performance
    Emous, R.A. van; Kwakkel, R.P. ; Krimpen, M.M. van; Brand, H. van den; Hendriks, W.H. - \ 2015
    Poultry Science 94 (2015)4. - ISSN 0032-5791 - p. 681 - 691.
    body-weight - feed restriction - reproductive-performance - recommended levels - maternal energy - sexual-maturity - egg-production - laying period - chick quality - frame size
    The objective of this study was to determine the effects of different growth patterns and dietary crude protein levels during rearing in broiler breeder females on fertility, hatchability, embryonic mortality, and offspring performance. A 2 × 3 factorial arrangement of treatments was used, with 2 growth patterns to reach a target body weight at 20¿wk of age of 2,200 g (standard = standard growth pattern) or 2,400 g (high = high growth pattern), and 3 dietary protein levels (high = crude protein, high), (medium = crude protein, medium), and low = crude protein, low). Fresh egg composition and organ development in hatchlings were determined. Offspring of the different groups were reared until an age of 34 d and feed intake, body weight gain, mortality, and carcass composition were determined. In 29-wk-old high growth pattern breeders compared to standard growth pattern breeders, fertility and hatchability of set eggs were increased; embryonic mortality between d 1 and 9 was decreased whereas hatchability of fertile eggs was not affected. Breeders fed the medium crude protein diet showed a decreased hatchability of fertile eggs caused by an increased embryonic mortality between d 18 and 21 compared to breeders fed the high crude protein and low crude protein diets. Offspring of 29-wk-old high growth pattern breeders tended (P = 0.059) to have a higher body weight at d 34 than offspring of standard growth pattern breeders, which was achieved by a tendency to a higher body weight gain (P = 0.057). Offspring of breeders fed the medium and low crude protein diet showed a higher feed intake between d 18 and 27 and during the total growth period, as compared to offspring of high crude protein breeders. Male broilers of low crude protein breeders had higher breast meat yield than male broilers of high crude protein breeders, while breast meat yield of female broilers was not affected by dietary protein levels. This experiment showed that a higher growth pattern during the rearing period increased fertility, decreased embryonic mortality, and improved offspring performance in young breeders, whereas decreased dietary protein level had no or less pronounced effects on these traits.
    Effects of ambient temperature, feather cover, and housing system on energy partitioning and performance in laying hens
    Krimpen, M.M. van; Binnendijk, G.P. ; Anker, I. van den; Heetkamp, M.J.W. ; Kwakkel, R.P. ; Brand, H. van den - \ 2014
    Journal of Animal Science 92 (2014)11. - ISSN 0021-8812 - p. 5019 - 5031.
    residual feed consumption - physical-activity - genetic-variation - egg-production - fowl - poultry - requirements - selection - patterns
    Environmental factors, such as ambient temperature (T), feather cover (FC), and housing system (HS), probably affect energy requirements of laying hens. Using a 3 × 2 × 2 factorial arrangement, interaction effects of T (11, 16, and 21°C), FC (100 and 50%), and HS (cage and floor housing) on energy partitioning and performance of laying hens were investigated. Six batches of 70 H&N Brown Nick laying hens, divided over 2 respiration chambers, were exposed to the T levels in three 2-wk periods. Heat production (HP) was determined by indirect calorimetry. The ME intake was calculated by subtracting energy in manure/litter from that in feed and wood shavings. The NE was calculated by subtracting HP from ME. The ME intake increased by 1% for each degree reduction in T. In hens with intact plumage, HP was not affected by T, whereas at decreasing T, HP increased in hens with 50% FC (P <0.01). At 21°C, HP was not affected by HS, whereas in the floor system, HP at 16 and 11°C was 5.8 and 3.0% higher, respectively, than in cages (P <0.05). The NE for production was 25.7% higher in cages compared to the floor system (P <0.05). In cages, 24.7% of NE for production was spent on body fat deposition, whereas in the floor system, 9.0% of NE for production was released from body fat reserves. The ME intake was predicted by the equation (R2 = 0.74) ME intake (kJ/d) = 612 BW0.75 – (8.54 × T) + (28.36 × ADG) + (10.43 × egg mass) – (0.972 × FC). Hen performances were not affected by treatments, indicating the adaptive capacity of young laying hens to a broad range of environmental conditions.
    Convergence and Divergence in Direct and Indirect Life-History Traits of Closely Related Parasitoids (Braconidae: Microgastrinae)
    Harvey, J.A. ; Visser, B. ; Lann, C. le; Boer, J.G. de; Ellers, J. ; Gols, R. - \ 2014
    Evolutionary Biology 41 (2014)1. - ISSN 0071-3260 - p. 134 - 144.
    wasp venturia-canescens - sexual size dimorphism - developmental strategies - reproductive strategies - evolutionary argument - development time - egg-production - body-size - host - hymenoptera
    Closely related species in nature often show similarities in suites of direct and indirect traits that reveal aspects of their phylogenetic history. Here we tested how common descent affects trait evolution in several closely related parasitoid species in the genera Cotesia and Microplitis (Hymenoptera: Braconidae: Microgastrinae) by comparing development, resource use and allocation into reproduction and maintenance. Parasitoids in these genera exhibit traits, like haemolymph feeding as larvae and external pupation that are rare in most parasitoid lineages. The growth of parasitized hosts was reduced by 90 % compared with healthy hosts, and maximum host size depended to a large extent on adult parasitoid size. Development time was longer in the more generalist parasitoids than in the specialists. Adult body mass was sexually dimorphic in all Cotesia species, with females being larger, but not in Microplitis spp. In contrast, in one of the Microplitis species males were found to be the larger sex. Egg load dynamics during the first 6 days after emergence were highly variable but egg number was typically higher in Cotesia spp. compared to Microplitis spp. Longevity in the various species was only greater in female than in male wasps in two Microplitis sp. There was a clear inverse relationship between resource use and allocation, e.g. maximum egg load and longevity, in these parasitoids. Our results reveal that adaptation to constraints imposed by host quality and availability has resulted in trait convergence and divergence at the species, genus and subfamily level.
    Effects of dietary dilution source and dilution level on feather damage, performance, behaviour, and litter condition in pullets
    Qaisrani, S.N. ; Krimpen, M.M. van; Kwakkel, R.P. - \ 2013
    Poultry Science 92 (2013)3. - ISSN 0032-5791 - p. 591 - 602.
    nonstarch polysaccharide concentration - laying hens - energy concentration - oat hulls - nutrient dilution - pecking behavior - particle sizes - egg-production - domestic-fowl - food-intake
    An experiment was conducted to investigate the effects of dietary dilution sources and levels on feather damage, performance, feeding behavior, and litter condition in rearing pullets. It was hypothesized that dietary dilution increases feeding-related behavior and improves feather condition, particularly if insoluble nonstarch polysaccharides are used as the dilution source. In total, 864 Lohmann Brown 1-d-old non-beak-trimmed pullets were used until 18 wk of age. Four dietary treatments, a control diet without any dilution (R_0%), 7.5% diluted diet with sunflower seed extract/oat hulls (R_7.5%), 15% diluted diet with sunflower seed extract (R_15%_S), and 15% diluted diet with oat hulls (R_15%_O), with 6 replicates (1 replicate is a pen with 36 pullets) per treatment were used. On 4-wk intervals, behavioral parameters, including eating time, feather pecking, feather condition, and general behavior were evaluated. Pullets fed the control diet showed increased feather, comb, and wire pecking compared with pullets fed diluted diets. The level of feather damage decreased with increasing dietary dilution level. Pullets receiving R_15%_S and R_15%_O showed more feeding-related behavior than the pullets on R_7.5% and R_0%. Oat hulls were more effective in preventing feather damage than sunflower seed extract. Pullets did not fully compensate their feed intake if fed a dietary dilution, resulting in a proportionally reduced available ME intake. The R_15%_O pullets had 2.9% lower average BW gain compared with those fed R_0%. Average eating duration increased by 12.8, 33.2, and 42.1% in R_7.5%, R_15%_S, and R_15%_O fed pullets, respectively, compared with R_0%, whereas eating rate [feed intake (g)/pullet per eating min] was decreased in R_15%_S and R_15%_O pullets. Relative weights of empty gizzards were 3.95, 10.30, and 62.72% greater in R_7.5%, R_15%_S, and R_15%_O pullets compared with pullets fed R_0%. It was concluded that dietary dilution affected time budgets of the pullets, as shown by more feeding-related behavior, resulting in less feather pecking behavior. Based on our results, application of this feeding strategy could improve production and welfare in pullets.
    Fear, stress, and feather pecking in commercial white and brown laying hen parent-stock flocks and their relationships with production parameters
    Haas, E.N. de; Kemp, B. ; Bolhuis, J.E. ; Groothuis, T. ; Rodenburg, T.B. - \ 2013
    Poultry Science 92 (2013)9. - ISSN 0032-5791 - p. 2259 - 2269.
    egg-production - circulating levels - manual restraint - broiler-chickens - furnished cages - genetic lines - behavior - corticosterone - welfare - performance
    Little is known about the relationship between welfare traits and production in laying hen parent stock (PS). In commercial laying hens and pure lines, it is known that aspects associated with reduced welfare such as high fear, stress, and feather pecking can have negative effects on production. Because PS hens are housed under different conditions than commercial laying hens, the relationship between welfare traits and production may differ. We therefore studied the fear response to a stationary person (SP) and novel object (NO), basal plasma corticosterone (CORT) and whole-blood serotonin levels (5-HT), and feather damage as a proxy for feather pecking in 10 Dekalb White (DW) and 10 ISA Brown (ISA) commercial PS flocks and related these to production data. Because the relationship between welfare traits and production may differ by genetic origin and group size, we also assessed genotype and group size effects. Dekalb White birds were more fearful of a SP, and had more feather damage and lower 5-HT levels than ISA birds. Genotypes did not differ in CORT. A large group size (n > 5,000) was associated with low feed intake and better feed conversion for ISA flocks. For DW flocks, high fear of the NO was associated with low BW, low egg weight, and low feed intake. For ISA flocks, high fear of the SP was associated with high mortality. For both lines, high CORT was related to low egg weight. This is the first study to associate levels of fear and CORT to production in commercial PS flocks. Management of PS flocks should take into account breed differences, group size effects, and effects of human-bird interactions. Further research is needed to determine the effects of fear, CORT, 5-HT, and feather damage in commercial PS flocks on the development of their offspring.
    Effects of growth patterns and dietary crude protein levels during rearing on body composition and performance in broiler breeder females during the rearing and laying period
    Emous, R.A. van; Kwakkel, R.P. ; Krimpen, M.M. van; Hendriks, W.H. - \ 2013
    Poultry Science 92 (2013)8. - ISSN 0032-5791 - p. 2091 - 2100.
    fed representative 1957 - reproductive-performance - feed restriction - egg-production - recommended levels - sexual maturity - frame size - weight - photostimulation - hens
    ABSTRACT The combined effects of growth pattern (GP) and dietary CP level during rearing (2 to 22 wk of age) on body composition and performance were investigated in broiler breeder females from 0 to 40 wk of age. One-day-old pullets (n = 768) were randomly allotted to 48 pens according to 2 growth patterns (standard = SGP and high = HGP) and fed using 1 of 3 dietary CP levels (high = CPh, medium = CPm, and low = CPl). From 19 to 22 wk of age, feeding level was gradually adjusted to obtain a similar target BW for all birds, and then until 40 wk of age, all birds received similar amounts of a standard breeder diet. During the rearing period, the HGP pullets were fed a higher feed intake level (6.5%) than SGP pullets. To meet BW targets at 22 wk of age, feed intake from d 14 onward had to be increased for the CPm (4.6%) and CPl (10.0%) treatments. Breast muscle percentages of HGP and SGP pullets were similar at any age, although abdominal fat pad at 20 wk was 0.18% higher for HGP pullets. Pullets fed the CPl diet had a lower breast muscle percentage compared with pullets fed the CPm and CPh diets (0.46 and 0.85% at wk 10, 0.81 and 1.45% at wk 20, respectively). Abdominal fat pads in CPl pullets were 0.18 and 0.22% (wk 10), and 0.24 and 0.42% (wk 20) higher compared with CPm and CPh pullets, respectively. At 40 wk of age, no effects on breast muscle and abdominal fat pad were found among all treatments. Egg production, sexual maturation, and egg weight were not affected by GP and CP levels during rearing. It was concluded that a low CP diet during rearing decreased breast muscle and increased abdominal fat pad, whereas a high GP only increased abdominal fat pad, at the end of the rearing period. Decreasing dietary CP level seems to be more effective in increasing abdominal fat pad than increasing GP.
    A model for an economically optimal replacement of a breeder flock
    Yassin, H. ; Velthuis, A.G.J. ; Giesen, G.W.J. ; Oude Lansink, A.G.J.M. - \ 2012
    Poultry Science 91 (2012)12. - ISSN 0032-5791 - p. 3271 - 3279.
    egg-production - broiler breeders - dairy-cattle - rejuvenated assets - hatchability - performance - policies - hens - age - decisions
    A deterministic model is developed to support the tactical and operational replacement decisions at broiler breeder farms. The marginal net revenue approach is applied to determine the optimal replacement age of a flock. The objective function of the model maximizes the annual gross margin over the flock’s production cycle. To calculate the gross margin, future egg production, fertility, or hatchability of the eggs, revenues and variable costs of a flock were estimated. For tactical decisions, the optimal laying length is the age at which the average gross margin of an average flock is maximal. For operational decisions, a flock should be replaced when the marginal gross margin of a replaceable flock is less than the average gross margin of an average flock. To demonstrate the model, a broiler breeder flock from a Dutch breeder farm was used. A sensitivity analysis showed that the optimal replacement decision, for both tactical and operational management, is sensitive to the decrease in the weekly egg production after the peak and the prices of feed and hatching eggs. The effect of the decrease in weekly fertility after the peak on the replacement decision is related to the payment system for hatching eggs. Key words: on-farm decision support tool , flock replacement decision , marginal net revenue approach , broiler breeder farm
    Qualitative use of Dynamic Energy Budget theory in ecotoxicology : case study on oil contamination and Arctic copepods
    Klok, T.C. ; Hjorth, M. ; Dahlloef, I. - \ 2012
    Journal of Sea Research 73 (2012). - ISSN 1385-1101 - p. 24 - 31.
    multiple end-points - calanus-finmarchicus - egg-production - population-level - toxicity tests - life-cycle - crude-oil - disko bay - eurytemora-affinis - individual growth
    The Dynamic Energy Budget (DEB) theory provides a logic and consistent framework to evaluate ecotoxicological test results. Currently this framework is not regularly applied in ecotoxicology given perceived complexity and data needs. However, even in the case of low data availability the DEB theory is already useful. In this paper we apply the DEB theory to evaluate the results in three previously published papers on the effects of PAHs on Arctic copepods. Since these results do not allow for a quantitative application we used DEB qualitatively. The ecotoxicological results were thereby set in a wider ecological context and we found a logical explanation for an unexpected decline in hatching success described in one of these papers. Moreover, the DEB evaluation helped to derive relevant ecological questions that can guide future experimental work on this subject
    Genetic variances, heritabilities and maternal effects on body weight, breast meat yield, meat quality traits and the shape of the growth curve in turkey birds
    Aslam, M.L. ; Bastiaansen, J.W.M. ; Crooijmans, R.P.M.A. ; Ducro, B.J. ; Vereijken, A. ; Groenen, M.A.M. - \ 2011
    BMC Genetics 12 (2011). - ISSN 1471-2156 - 9 p.
    egg-production - parameters - selection - chickens - reproduction - models - generations - broilers - patterns - impact
    Background Turkey is an important agricultural species and is largely used as a meat bird. In 2004, turkey represented 6.5% of the world poultry meat production. The world-wide turkey population has rapidly grown due to increased commercial farming. Due to the high demand for turkey meat from both consumers and industry global turkey stocks increased from 100 million in 1970 to over 276 million in 2004. This rapidly increasing importance of turkeys was a reason to design this study for the estimation of genetic parameters that control body weight, body composition, meat quality traits and parameters that shape the growth curve in turkey birds. Results The average heritability estimate for body weight traits was 0.38, except for early weights that were strongly affected by maternal effects. This study showed that body weight traits, upper asymptote (a growth curve trait), percent breast meat and redness of meat had high heritability whereas heritabilities of breast length, breast width, percent drip loss, ultimate pH, lightness and yellowness of meat were medium to low. We found high positive genetic and phenotypic correlations between body weight, upper asymptote, most breast meat yield traits and percent drip loss but percent drip loss was found strongly negatively correlated with ultimate pH. Percent breast meat, however, showed genetic correlations close to zero with body weight traits and upper asymptote. Conclusion The results of this analysis and the growth curve from the studied population of turkey birds suggest that the turkey birds could be selected for breeding between 60 and 80 days of age in order to improve overall production and the production of desirable cuts of meat. The continuous selection of birds within this age range could promote high growth rates but specific attention to meat quality would be needed to avoid a negative impact on the quality of meat.
    Effects of nutrient dilution and nonstarch polysaccharide concentration in rearing and laying diets on eating behavior and feather damage of rearing and laying hens
    Krimpen, M.M. van; Kwakkel, R.P. ; Peet-Schwering, C.M.C. van der; Hartog, L.A. den; Verstegen, M.W.A. - \ 2009
    Poultry Science 88 (2009)4. - ISSN 0032-5791 - p. 759 - 773.
    pecking behavior - feeding-behavior - egg-production - domestic-fowl - wood shavings - whole grain - performance - chicks - mortality - poultry
    An experiment was conducted with 768 non-cage-housed ISA Brown pullets, of which 576 hens were followed during the laying period, to investigate the separate effects of dietary energy dilution and non-starch polysaccharides (NSP) concentration (oat hulls as NSP source) on eating behavior and feather damage. Day-old pullets were allotted to 1 of 6 dietary treatments according to a 3 x 2 factorial arrangement (3 dilution and 2 NSP levels), with 8 replicates (pens) per treatment. At 17 wk of age, pens with hens were allotted to 1 of 8 dietary treatments according to a 4 x 2 factorial arrangement (4 dilution and 2 NSP levels), with 6 replicates per treatment. Compared with 0% dilution level, feed intake of laying hens of 10, 15, and 20% dilution levels increased by 8.4% (9.5 g/hen per d), 16.5% (18.1 g/hen per d), and 20.9% (23.6 g/hen per d), respectively. The MEn intake was similar for all dilution levels. Hens fed standard-NSP laying diets had similar insoluble NSP intake for all dilution levels (9.3 g/hen per d). Insoluble NSP intake of hens fed high-NSP laying diets increased from 15.6 g/hen per day (0% dilution) to 18.9 g/hen per day (20% dilution). Providing high- vs. standard-NSP layer diet decreased relative proventriculus contents (1.1 vs. 0.3 g/kg of BW) and increased empty gizzard weight (14.3 vs. 24.4 g/kg of BW). Hens that were fed standard-NSP diets had more feather damage compared with hens fed high-NSP diets (0.58 vs. 0.30 arbitrary units). Increasing the insoluble NSP intake resulted in decreased proventricular weight and increased gizzard weight and its contents, which are indicators of improved functioning of the gut, thereby linearly reducing feather damage. Providing diluted rearing diets increased feed intake from the first weeks of life onwards. It was hypothesized that pullets were increasingly "imprinted" on feed as pecking substrate if dilution level increased. This may decrease feather pecking and could explain the improved feather condition at 49 wk of age when 15% diluted rearing diet was fed
    Life-history traits in closely related secondary parasitoids sharing the same primary parasitoid host: evolutionary opportunities and constraints
    Harvey, J.A. ; Wagenaar, R. ; Bezemer, T.M. - \ 2009
    Entomologia Experimentalis et Applicata 132 (2009)2. - ISSN 0013-8703 - p. 155 - 164.
    egg-production - body-size - hymenopteran parasitoids - reproductive strategies - endoparasitoid wasp - cotesia-glomerata - asobara-tabida - lysibia-nana - trade-off - allocation
    Thus far, few studies have compared life-history traits amongst secondary parasitoids attacking and developing in cocoons of their primary parasitoid hosts. This study examines development and reproduction in Lysibia nana Gravenhorst and Acrolyta nens Hartig (both Hymenoptera: Ichneumonidae), two related and morphologically similar secondary parasitoids that attack pupae of the gregarious endoparasitoid, Cotesia glomerata L. (Hymenoptera: Braconidae). On black mustard, Brassica nigra L. (Brassicaceae) plants in a field plot, adults of L. nana and A. nens frequently emerged from the same cocoon broods of C. glomerata. Based on similarities in their phylogeny and morphology, it was hypothesized that both species would exhibit considerable overlap in other life-history traits. In both L. nana and A. nens, adult wasp size increased with host cocoon mass at parasitism, although L. nana wasps were slightly larger than A. nens wasps, and completed their development earlier. Adult females of both species emerged with no eggs but matured eggs at similar rates over the following days. When provided with 20 host cocoons daily, fecundity in female L. nana was slightly more skewed towards early life than in A. nens, although lifetime fecundity did not differ between the two species. Longevity was significantly reduced in females of both species that were provided with hosts. Both parasitoids were found to exhibit strong similarities in life-history and development traits and in their ecological niche, thereby supporting our general hypothesis. Competition between L. nana and A. nens is presumably diffused because their preferred host (C. glomerata) is relatively abundant in open habitats.
    Low Dietary Energy Concentration, High Nonstarch Polysaccharide Concentration, and Coarse Particle Sizes of Nonstarch Polysaccharides Affect the Behavior of Feather-Pecking-Prone Laying Hens
    Krimpen, M.M. van; Kwakkel, R.P. ; Peet-Schwering, C.M.C. van der; Hartog, L.A. den; Verstegen, M.W.A. - \ 2008
    Poultry Science 87 (2008). - ISSN 0032-5791 - p. 485 - 496.
    egg-production - performance - protein - strains - plumage - hybrids - layers - fiber - whole
    An experiment was conducted with 504 non-cage-housed ISA Brown laying hens from 18 to 40 wk of age to investigate the separate effects of dietary energy concentration, nonstarch polysaccharide (NSP) concentration, and particle sizes of added NSP source on the eating behavior, feather-pecking behavior, and hen performance of laying hens. Hens were allotted to 1 of 6 dietary treatments according to a 2 x 3 factorial arrangement, with 7 replicates per treatment. The factors were control and low energy concentration (2,825 vs. 2,540 kcal/kg), control and high NSP concentration (133 vs. 195 g/kg), and fine vs. coarse particle size of the added NSP source in the high-NSP diets. We hypothesized that eating time would be increased by feeding low-energy diets or coarsely ground, high-NSP diets, or both, resulting in reduced feather-pecking behavior, without negatively affecting hen performance. Energy reduction, NSP addition, and coarse grinding of NSP increased eating time by 14.2% (P = 0.001), 17.2% (P <0.001), and 7.9% (P = 0.075), respectively, compared with the control level of these factors. Addition of NSP decreased eating rate (g/min) by 21.0% (P = 0.010). Layers already performed gentle feather-pecking behavior during the fifth week of the rearing period. Dietary treatments did not affect the maximal level of feather condition scores, but arise of feather damage was delayed by 10 wk in hens fed low-energy, coarsely ground, NSP-rich diets compared with hens fed control diets. Hens fed the control NSP diets showed reduced culling rates, because of less cannibalistic pecking, when energy concentration was decreased (44.1 vs. 13.1%), whereas in the high-NSP diets, culling rate decreased slightly when hens were fed the low-energy diets (31.6 vs. 28.6%; P = 0.071). Hens that were fed the low-energy diets compensated for the 10% reduction in energy concentration by a 9.3% higher maximal feed intake (143.0 vs. 130.8 g/d). Hen performance and BW gain of the hens were not affected by dietary treatments. We concluded that hens that were fed low-energy or high (coarsely ground)-NSP diets spend more time on feed intake, compared with hens that were fed the control diets. As a result, hens in some treatments showed less feather-pecking behavior.
    Partial duplication of the PRLR and SPEF2 genes at the late feathering locus in chicken
    Elferink, M.G. ; Vallee, N. ; Jungerius, B.J. ; Crooijmans, R.P.M.A. ; Groenen, M.A.M. - \ 2008
    BMC Genomics 9 (2008). - ISSN 1471-2164 - 9 p.
    leukosis virus-infection - receptor knockout mice - wool follicle growth - signal-transduction - egg-production - hair follicle - prolactin - expression - transmission - association
    Background One of the loci responsible for feather development in chickens is K. The K allele is partially dominant to the k+ allele and causes a retard in the emergence of flight feathers at hatch. The K locus is sex linked and located on the Z chromosome. Therefore, the locus can be utilized to produce phenotypes that identify the sexes of chicks at hatch. Previous studies on the organization of the K allele concluded the integration of endogenous retrovirus 21 (ev21) into one of two large homologous segments located on the Z chromosome of late feathering chickens. In this study, a detailed molecular analysis of the K locus and a DNA test to distinguish between homozygous and heterozygous late feathering males are presented. Results The K locus was investigated with quantitative PCR by examining copy number variations in a total of fourteen markers surrounding the ev21 integration site. The results showed a duplication at the K allele and sequence analysis of the breakpoint junction indicated a tandem duplication of 176,324 basepairs. The tandem duplication of this region results in the partial duplication of two genes; the prolactin receptor and the gene encoding sperm flagellar protein 2. Sequence analysis revealed that the duplication is similar in Broiler and White Leghorn. In addition, twelve late feathering animals, including Broiler, White Leghorn, and Brown Layer lines, contained a 78 bp breakpoint junction fragment, indicating that the duplication is similar in all breeds. The breakpoint junction was used to develop a TaqMan-based quantitative PCR test to allow distinction between homozygous and heterozygous late feathering males. In total, 85.3% of the animals tested were correctly assigned, 14.7% were unassigned and no animals were incorrectly assigned. Conclusion The detailed molecular analysis presented in this study revealed the presence of a tandem duplication in the K allele. The duplication resulted in the partial duplication of two genes; the prolactin receptor and the gene encoding sperm flagellar protein 2. Furthermore, a DNA test was developed to distinguish between homozygous and heterozygous late feathering males.
    Genetic variation at the tumor virus B locus in commercial and labratory chicken populations assessed by a medium-throughput or a high-throughput assay
    Zhang, H.M. ; Bacon, L.D. ; Heidari, M. ; Muir, W.M. ; Groenen, M.A.M. ; Albers, G.A. ; Rattink, A.P. - \ 2007
    Avian Pathology 36 (2007)4. - ISSN 0307-9457 - p. 283 - 291.
    avian-leukosis virus - rous-sarcoma virus - mareks-disease vaccines - endogenous viral genes - subgroup-b - white leghorns - egg-production - immune-response - feathering dams - tvb locus
    The tumour virus B (TVB) locus encodes cellular receptors mediating infection by three subgroups of avian leukosis virus (B, D, and E). Three major alleles, TVB*S1, TVB*S3, and TVB*R, have been described. TVB*S1 encodes a cellular receptor mediating infection of subgroups B, D, and E. TVB*S3 encodes the receptor for two subgroups, B and D, and TVB*R encodes a dysfunctional receptor that does not permit infection by any of the subgroups, B, D, or E. Genetic diversity at the TVB locus of chickens was investigated in both layer and broiler commercial pure lines and laboratory lines. Genotyping assays were developed for both medium-throughput and high-throughput analysis. Of the 36 broiler lines sampled, 14 were fixed for the susceptible allele TVB*S1. Across all broiler lines, 83% of chickens were typed as TVB*S1/*S1, 3% as TVB*R/*R, and 14% as TVB*S1/*R. In the egg-layer lines, five of the 16 tested were fixed for TVB*S1/*S1. About 44% of egg-layers were typed as TVB*S1/*S1, 15% as TVB*R/*R, with the rest segregating for two or three of the alleles. In the laboratory chickens, 60% were fixed for TVB*S1/*S1, 6% for TVB*S3/*S3, 14% for TVB*R/*R, and the rest were heterozygotes (TVB*S1/*S3 or TVB*S1/*R). All commercial pure lines examined in this study carry the TVB*S1 allele that sustains the susceptibility to avian leukosis viruses B, D, and E. More importantly, the TVB*R allele was identified in multiple populations, thus upholding the opportunities for genetic improvement through selection.
    Energy Partitioning and Thyroid Hormone Levels During Salmonella enteritidis Infections in Pullets with High or Low Residual Feed Intake
    Eerden, E. van; Brand, H. van den; Heetkamp, M.J.W. ; Decuypere, M.P. ; Kemp, B. - \ 2006
    Poultry Science 85 (2006)10. - ISSN 0032-5791 - p. 1775 - 1783.
    growing layer hens - laying hens - food-consumption - divergent selection - growth-hormone - egg-production - body-weight - efficiency - chicken - lines
    This experiment was conducted to investigate whether feed efficiency, as measured by residual feed intake as a phenotypic trait, affects energy partitioning in pullets that have received Salmonella inoculation as an immune challenge. In each of 8 trials, energy partitioning was measured during 5 wk in 15-wk-old efficient (R¿) and nonefficient (R+) pullets, which were housed per efficiency group in 2 identical climate respiration chambers. After 1 wk of adaptation, the pullets in 4 trials were orally inoculated with 108 cfu of Salmonella enteritidis; pullets in the remaining trials were not inoculated and served as controls. Heat production was calculated from continuous recordings of O2 consumption and CO2 production. Energy and N partitioning were recorded on a weekly basis. Blood samples for analyses on thyroid hormones were taken at 16, 17, and 19 wk of age. There were no interactions between efficiency type and Salmonella treatment or Salmonella treatment effects in energy partitioning, except for a short-term increase in heat production in inoculated pullets. Nonefficient pullets had higher gross energy and ME intake, higher estimated ME for maintenance, lower ME:gross energy ratio, and higher total heat production and nonactivity-related heat production compared with R¿ pullets. Triiodothyronine levels in R+ pullets were higher at 16 and 17 wk but were lower at 19 wk of age compared with R¿ pullets. Thyroxine levels were higher in R¿ at 16 wk and showed interactions between efficiency type and Salmonella treatment at 17 and 19 wk of age. Body weights and spleen weights did not differ between efficiency groups. Nonefficient pullets had higher heart, liver, and ovary weights and more large yellow follicles than R¿ pullets. There were no Salmonella effects on body and organ weights. We conclude that R+ pullets have a faster running energy metabolism and that they put more resources into organ development than R¿ pullets. Inoculation with Salmonella has a short-term effect on nonactivity-related heat production but does not affect energy partitioning, regardless of efficiency type
    Impact of feeding management on feather pecking in laying hens
    Krimpen, M.M. van; Kwakkel, R.P. ; Reuvekamp, B.F.J. ; Peet-Schwering, C.M.C. van der; Hartog, L.A. den; Verstegen, M.W.A. - \ 2005
    Worlds Poultry Science Journal 61 (2005)4. - ISSN 0043-9339 - p. 663 - 686.
    dietary-protein source - different housing systems - open-field response - 2 different ages - plumage condition - egg-production - broiler-chickens - light-intensity - growing bantams - layer pullets
    In the near future EU-legislation will ban the use of conventional battery cages, while national legislation in some countries in Western Europe will ban beak trimming as well. The ban on battery cages and beak trimming causes an increased risk of feather pecking and cannibalism in laying hens. Many factors influence feather pecking behaviour, but this paper focuses on nutritional factors. Nutritional factors can have positive and negative effects on feather pecking behaviour in laying hens. Severe feather pecking has been demonstrated in birds that were fed a too low mineral level in the diet, a too low protein level or a too low amino acid level (methionine, arginine). Sometimes somewhat more feather pecking was found when layers were fed diets with mainly vegetable protein sources as compared with diets with protein from animal origin. Also more feather pecking may occur when the diets were fed restrictedly, fed coarsely ground, or fed as pellets. Feeding high-fibre diets, low energy diets, or roughages reduced feather pecking. Providing additional grain or straw in the litter during rearing could result in lower levels of feather pecking behaviour in adult stages. Some of these positive effects on feather pecking seem to be related to the time birds spend on feed intake and foraging. This paper gives an overview of the relationships between the occurrence of feather pecking behaviour and nutritional factors, such as diet composition and feeding strategies in laying hens.
    Importance of host feeding for parasitoids that attack honeydew-producing hosts
    Burger, J.M.S. ; Komany, A. ; Lenteren, J.C. van; Vet, L.E.M. - \ 2005
    Entomologia Experimentalis et Applicata 117 (2005)2. - ISSN 0013-8703 - p. 147 - 154.
    lifetime reproductive success - encarsia-formosa - trialeurodes-vaporariorum - aphytis-melinus - insect parasitoids - bemisia-tabaci - egg-production - hymenoptera - wasp - strategies
    Insect parasitoids lay their eggs in arthropods. Some parasitoid species not only use their arthropod host for oviposition but also for feeding. Host feeding provides nutrients to the adult female parasitoid. However, in many species, host feeding destroys an opportunity to oviposit. For parasitoids that attack Homoptera, honeydew is a nutrient-rich alternative that can be directly imbibed from the host anus without injuring the host. A recent study showed that feeding on host-derived honeydew can be an advantageous alternative in terms of egg quantity and longevity. Here we explore the conditions under which destructive host feeding can provide an advantage over feeding on honeydew. For 5 days, Encarsia formosa Gahan (Hymenoptera: Aphelinidae) parasitoids were allowed daily up to 3 h to oviposit until host feeding was attempted. Host feedings were either prevented or allowed and parasitoids had ad libitum access to honeydew between foraging bouts. Even in the presence of honeydew, parasitoids allowed to host feed laid more eggs per hour of foraging per host-feeding attempt than parasitoids that were prevented from host feeding. The higher egg-laying rate was not compromised by survival or by change in egg volume over time. In conclusion, host feeding can provide an advantage over feeding on honeydew. This applies most likely under conditions of high host density or low extrinsic mortality of adult parasitoids, when alternative food sources cannot supply enough nutrients to prevent egg limitation. We discuss how to integrate ecological and physiological studies on host-feeding behavior
    Influence of adult nutrition on the relationship between body size and reproductive parameters in a parasitoid wasp
    Bezemer, T.M. ; Harvey, J.A. ; Mills, N.J. - \ 2005
    Ecological Entomology 30 (2005)5. - ISSN 0307-6946 - p. 571 - 580.
    clutch size - egg-production - bracon-hebetor - host - fitness - hymenoptera - life - field - age - oviposition
    1. An important constraint upon life-history evolution in parasitoids is the limit imposed by body size on allocation of limited metabolic resources to different fitness-related physiological functions such as reproduction and survival. 2. The influence of adult nutrition on reproductive and maintenance variables was studied in the synovigenic ectoparasitoid Mastrus ridibundus, and it was determined whether resource allocation to these different functions depends on body size. 3. Over the course of adult life there was a positive relationship between body size and the number of mature eggs in adult females both in the presence and absence of food. However, only in the presence of food did egg maturation rates increase significantly with body size. Starved wasps produced significantly smaller eggs than fed ones, which has not been documented before. Moreover, starved wasps produced fewer offspring than fed wasps, and attacked fewer hosts. 4. The availability of food had a major effect on longevity, with fed females living about 10 times longer than starved ones. There was also a positive relationship between body size and longevity. In starved wasps, this relationship was the same both in the presence and absence of hosts, but in fed wasps there was a positive relationship between body size and longevity in the absence of hosts only. Allocation to initial eggs relative to lifetime progeny production did not decline with body size. 5. The data reveal that in M. ridibundus the trade-off between maintenance and reproduction varies with life expectancy
    Host preference of Callosobruchus maculatus: a comparison of life history characteristics for three strains of beetles on two varieties of cowpea
    Boeke, S.J. ; Loon, J.J.A. van; Huis, A. van; Dicke, M. - \ 2004
    Journal of Applied Entomology 128 (2004)6. - ISSN 0931-2048 - p. 390 - 396.
    f coleoptera - fabricius coleoptera - egg-production - seed beetle - bruchidae - oviposition - susceptibility - resistance - fecundity - size
    The reproductive success of Callosobruchus maculatus Fabricius, the main insect pest of stored cowpea, may vary between strains of this beetle and between varieties of the host seeds. Life history parameters of beetle strains from three different origins in West Africa were compared on two susceptible varieties of cowpea, Vigna unguiculata (L.) Walp. All beetle strains were assayed in a no-choice and a two-choice test. No major differences were found between the beetle strains. In a no-choice situation, the developmental period from egg to adult was prolonged on the bean variety Kpodjiguegue. In a two-choice situation, the beetles showed a strong preference for the Californian blackeyed bean variety to oviposit on. Here again the development took longer on Kpodjiguegue beans and the intrinsic rate of increase of the beetle population was lower. Using either equal numbers of beans of the same size or equal weights of beans of undetermined size of the two bean varieties did not affect the outcome of the test.
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