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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    Effects of incubation temperature pattern on broiler performance
    Wijnen, H.J. ; Molenaar, R. ; Roovert-Reijrink, I.A.M. van; Pol, C.W. van der; Kemp, B. ; Brand, H. van den - \ 2020
    Poultry Science 99 (2020)8. - ISSN 0032-5791 - p. 3897 - 3907.
    broiler - chick quality - eggshell temperature - growth performance - incubation

    During incubation, development of embryos is affected by eggshell temperature (EST). A constant EST of 37.8°C has been considered so far to result in most optimal embryo development. However, it can be hypothesized that a higher EST in week 2 in combination with a lower EST in week 3 stimulates embryo development and subsequent grow-out performance. In this study, 468 eggs of a 44-week-old Ross 308 breeder flock were incubated at different incubation temperature patterns in a 2 × 2 factorial arrangement. In week 2, EST was either 37.8°C or 38.9°C, and in week 3, EST was either 37.8°C or 36.7°C. At hatch, chick quality was determined. Thereafter, 320 broilers were grown in 32 pens (8 replicates/treatment) for 6 wk. Weekly BW and ADFI were determined, and at day 40, slaughter yield from 128 broilers (4 per pen) was determined. Results showed that EST in week 2 did not interact with EST in week 3 for any variable. An EST of 38.9°C in week 2 resulted in a 1 mm longer chick length (P < 0.001) and 0.4 mmol/L lower blood glucose level (P = 0.04) at hatch than an EST of 37.8°C. Grow-out performance was not affected by EST in week 2 of incubation. An EST of 36.7°C in week 3 resulted in a 1 mm shorter chick length (P = 0.02), 1.0 mmol/L higher blood glucose level (P < 0.001), and higher relative heart (P = 0.01) and stomach weights (P = 0.03) at hatch than an EST of 37.8°C. Additionally, an EST of 36.7°C in week 3 resulted in lower BW, ADG, and ADFI on slaughter age (all P < 0.03) than an EST of 37.8°C. In conclusion, no interaction between EST in week 2 and 3 of incubation was found for any variable. A higher EST in week 2 had minor effects at hatching and during rearing, whereas a lower EST in week 3 seemed to result in better organ development, but resulted in lower grow-out performance.

    Effects of reduced crossover recombination on quantitative trait analysis
    Wijnen, Cristian Lucas - \ 2019
    Wageningen University. Promotor(en): J.J.B. Keurentjes; F.A. van Eeuwijk, co-promotor(en): T.G. Wijnker; M.P. Boer. - Wageningen : Wageningen University - ISBN 9789463951203 - 175

    During meiosis, i.e. the production of the reproductive cells, the number of chromosomes in the cells is halved to ensure that after fertilization the typical quantity of chromosomes is restored. Crossover recombination is an essential step in this process that serves a dual function. On the one hand crossovers ensure the proper segregation of homologous chromosomes and thus ensure the reduction in chromosome number. In addition, crossovers result in the exchange of genetic material between homologous chromosomes. Reshuffling of genetic material is useful for identifying the effects of certain chromosomal segments on phenotypes when specific chromosome segments co-segregate with specific traits. But if this happens at multiple locations and chromosomes simultaneously it can also obscure the detection of those genetic effects. This thesis addresses the question as to how crossover recombination affects the detection of quantitative traits.

    The effects of crossover recombination on the detection of quantitative trait loci (QTLs) are explored in this thesis by using doubled haploid (DH) populations in Arabidopsis thaliana. As opposed to more traditional mapping populations like recombinant inbred lines, these doubled haploids show lower numbers of crossover events since a doubled haploid experienced only one round of meiosis. In this thesis, some doubled haploids were derived from a modified meiosis because of which they have reduced crossover recombination, or show the complete absence of crossovers. DH derived from a hybrid without crossover recombination are so-called chromosome substitution lines (CSLs). In multiple other species, CSLs are credited to detect QTLs with relative ease due to their simple genetic architecture. Additionally, combinations of CSLs can be used to detect genetic interactions. In this thesis it is explored how genetic analysis can be performed with different sets of CSLs and doubled haploids with reduced crossover recombination. Chapter 1 further elaborates on the potential use of CSLs and some of the basics of quantitative trait analysis and QTL mapping are explained.

    When doubled haploids are made in Arabidopsis, one first produced monoploid (haploid) plants that then give rise to doubled haploids. In Chapter 2 monoploids and their subsequent doubled haploids were generated, and their phenotypes compared in a genetic analysis to assess the effect of ploidy on their phenotypes. This resulted in detection of QTLs specific for a single ploidy level and QTLs that were expressed in both mono- and diploid generations. The ploidy specific QTLs indicated a different response of the genotypes to the change in ploidy, which was hypothesized to be a response to the sterility of the monoploids. The DH population itself was also used in a QTL mapping approach for flowering time measured in vernalized and non-vernalized conditions. This resulted in the detection of genotype-by-environment QTLs. Although this confirmed that reduction of crossover recombination (in Doubled haploids) does not per se influence genetic mapping, in the following chapters active measures were taken to repress the number of crossover recombinations.

    In 2014 reverse breeding was presented as a method in which the parental lines of an F1 hybrid could be recreated by the combined use of complete suppression of crossover recombination through a stable knock-down of the meiotic recombinase DMC1 followed by the generation of doubled haploid plants from F1 hybrid. In Chapter 3 the same approach was used to obtain offspring with no crossover recombination to collect all possible CSL genotypes of a biparental cross. Additionally backcross populations of single chromosome substitution lines (sCSL) with their respective recurrent parent were created. Each of these populations represent a family of lines that segregate for a single chromosome. While the CSLs serve to identify the QTL effects, these single chromosome segregating families were used to finemap major QTL effects. In this thesis it is shown that also for Arabidopsis QTLs can be identified with relative ease in CSLs. Additionally, by acquiring all the different combinations of CSL genotypes, one can also look for genetic interactions between chromosomes. Genetic interaction effects are assumed to occur when the phenotype of an individual in which two independent loci are substituted cannot be predicted based on the individual effects of those two loci. In Chapter 3 such interaction effects between chromosomes are identified for two traits (flowering time and main stem length). Such genetic interaction effects are shown to have effect sizes equal to typical QTLs effect sizes. This demonstrates the advantage of discovering possible genetic interactions using such CSL populations.

    The experiment to detect epistasis (i.e. genetic interactions) using a panel of all possible CSL genotypes in Chapter 3 was limited to only two phenotypes. This did not allow generalizations on how frequent epistasis is observed. This question was in part answered in Chapter 4, where a shotgun-proteomics approach was used to detect main effects and interaction effects between chromosomes for the abundance of proteins. Especially a small but genetically diverse panel of CSLs allows the detection of genetic effects at the proteome level, which was so far not technologically feasible in a cost-efficient approach. Only a subset of CSLs was used, which illustrates that a limited set of fourteen genotypes with single and double substitutions in a recurrent background can be used to detect genetic effects. Using protein abundancy as a phenotype, more than a thousand QTLs divided over the different chromosomes were identified. Especially chromosomes 2 and 5 were identified as contributors to the proteome variation. Furthermore, it was shown that the abundance of approximately 20% of the measured proteins was significantly dependent on the presence of a combination of two chromosomes (i.e. an interaction effect). Furthermore, for several proteins their abundance was not influenced by the allelic state of any single chromosome, but they were only significantly influenced by a combination of chromosomes. This shows that interaction effects can also be detected when a limited number of CSLs are used.

    The previous chapters deal with confirming the utility of CSLs, Chapter 5 addresses several practical difficulties of the application of reduced crossover recombination to advance plant breeding practice. Because proper homolog segregation is compromised in the absence of crossover recombination, plants produce high numbers of non-viable spores and have a very low fertility. In Chapter 5 the effect is studied of the knock down of MSH5 instead of DMC1. With a dysfunctional MSH5 crossover recombination is not completely absent but suppressed to retain still a few crossovers per meiosis. Therefore, proper homolog segregation occurs more often, and plants remain more fertile. Additionally, instead of stable suppression via transformation of a parental line, virus-induced-gene-silencing (VIGS) is used to transiently downregulate the gene MSH5 in the meiosis of a hybrid directly. Both revisions together ensure transgene-free progeny in only three generations with a few or no recombination events per offspring. Using such progeny, the original starting hybrid could be recreated using complementing non-crossover offspring which did not differ phenotypically from the original hybrid. Additional intercrosses were made between non-crossover and offspring containing few crossovers that were complementary for most of the genome to produce hybrids with small homozygous segments. In general, such near-full hybrids did not differ phenotypically from the original hybrids with only few exceptions. This suggests that one could improve hybrids directly by fixating specific segments containing for instance recessive QTLs. The improvements to reverse breeding make this breeding approach more efficient and flexible for application to higher chromosome number species.

    In Chapter 6 a discussion follows on the previous chapters. Also new and additional experiments are proposed based on the observations described in the different chapters. It is argued that a complete CSL panel with all possible CSL genotypes can give a better overview of the genetic architecture controlling quantitative traits, especially when multiple interacting QTLs are to be expected. Smaller panels of CSLs might be informative enough for the purpose of genetic mapping in high chromosome number species, and practical considerations should include the type of genetic effects one wants to identify and the known genetics of the considered trait. Taken together, the work in this thesis shows that with different approaches reduced crossover recombination can additional advantages on the analysis of quantitative traits.

    Mapping soil biodiversity in Europe and the Netherlands
    Rutgers, M. ; Leeuwen, J.P. van; Vrebos, Dirk ; Wijnen, Harm J. van; Schouten, Ton ; Goede, R.G.M. de - \ 2019
    Soil Systems 3 (2019)2. - ISSN 2571-8789 - 17 p.
    Soil is fundamental for the functioning of terrestrial ecosystems, but our knowledge about soil organisms and the habitat they provide (shortly: Soil biodiversity) is poorly developed. For instance, the European Atlas of Soil Biodiversity and the Global Soil Biodiversity Atlas contain maps with rather coarse information on soil biodiversity. This paper presents a methodology to map soil biodiversity with limited data and models. Two issues were addressed. First, the lack of consensus to quantify the soil biodiversity function and second, the limited data to represent large areas. For the later issue, we applied a digital soil mapping (DSM) approach at the scale of the Netherlands and Europe. Data of five groups of soil organisms (earthworms, enchytraeids, micro-arthropods, nematodes, and micro-organisms) in the Netherlands were linked to soil habitat predictors (chemical soil attributes) in a regression analysis. High-resolution maps with soil characteristics were then used together with a model for the soil biodiversity function with equal weights for each group of organisms. To predict soil biodiversity at the scale of Europe, data for soil biological (earthworms and bacteria) and chemical (pH, soil organic matter, and nutrient content) attributes were used in a soil biodiversity model. Differential weights were assigned to the soil attributes after consulting a group of scientists. The issue of reducing uncertainty in soil biodiversity modelling and mapping by the use of data from biological soil attributes is discussed. Considering the importance of soil biodiversity to support the delivery of ecosystem services, the ability to create maps illustrating an aggregate measure of soil biodiversity is a key to future environmental policymaking, optimizing land use, and land management decision support taking into account the loss and gains on soil biodiversity.
    Modelling global river export of microplastics to the marine environment : Sources and future trends
    Wijnen, Jikke van; Ragas, Ad M.J. ; Kroeze, Carolien - \ 2019
    Science of the Total Environment 673 (2019). - ISSN 0048-9697 - p. 392 - 401.
    Coastal seas - Future scenarios - GREMiS model - Microplastics - Plastic soup - River transport

    Microplastics, transported by rivers to oceans, are triggering environmental concern. This study aims to better understand river export of microplastics from land to sea. We developed the Global Riverine Export of Microplastics into Seas (GREMiS) model, a global, spatially explicit model for analysing the annual microplastics export to coastal seas. Our results indicate that riverine microplastics export varies among world regions, with several hotspots, e.g., South East Asia, and, depending on the 2050 scenario, may be doubled (‘Business as usual’) or halved due to improved waste management (‘Environment profits’). Globally, our model simulations indicated fragmentation of macroplastics as the main source of microplastics, but this result heavily depends on the assumed fragmentation rate. Sewerage discharges contributed only 20%, ranging from 1% (Africa) to 60% (OECD countries) and decreasing by 2050 as a result of improved sanitation. We conclude that, combating microplastics in the aquatic environment requires more region-specific analyses.

    Can we reduce pre-weaning piglet losses with maternal nitrate supplementation around farrowing
    Bosch, M. van den; Wijnen, H.J. ; Linde, Irene van de; Brand, H. van den - \ 2019
    In: Trade-offs in science – keeping the balance. - Wageningen University & Research - p. 32 - 32.
    Effects of maternal dietary nitrate supplementation during the perinatal period on piglet survival, body weight, and litter uniformity
    Bosch, M. van den; Wijnen, H.J. ; Linde, I.B. van der; Wesel, A.A.M. van; Melchior, D. ; Kemp, B. ; Clouard, C.M. ; Brand, H. van den - \ 2019
    Translational Animal Science 3 (2019)1. - ISSN 2573-2102 - p. 464 - 472.
    The objective of this study was to evaluate effects of different dosages of dietary nitrate supplementation to sows from d 108 of gestation until d 5 of lactation on reproductive performance of sows and piglet performance from birth until weaning. Dietary nitrate supplementation leads to nitric oxide (NO) formation that can potentially increase blood flow to the fetuses (by the vasodilative effect of NO), leading to a decrease in the loss of potential viable piglets in the form of stillbirth and preweaning mortality. Three hundred and five gilts and sows were allocated to one of six diets from d 108 of gestation until d 5 of lactation, containing 0.00% (Control), 0.03%, 0.06%, 0.09%, 0.12%, or 0.15% of dietary nitrate. The source of nitrate used was calcium nitrate double salt. Calcium levels were kept the same among diets by using limestone. Gilts and sows were weighed and backfat was measured at arrival to the farrowing room (d 108 of gestation) and at weaning (d 27 of age). Data included number of piglets born alive, born dead, and weaned, as well as individual piglet weights at d 0, 72 h of age and weaning. Preweaning mortality was determined throughout lactation.Body weight d 0 (P = 0.04) as well as BW at 72 h of age (P < 0.01) increased linearly with increasing dosages of nitrate in the maternal diet. Litter uniformity (SD) at birth was not affected by maternal nitrate supplementation level (P > 0.10), but tended to be higher at 72 h of age in the control treatment than in all nitrate-supplemented treatments (P = 0.07), and SD decreased linearly (increased uniformity) at weaning with increasing dosages of nitrate (P = 0.05). BW at weaning (P > 0.05) and average daily gain of piglets during lactation (P > 0.05) were not affected by maternal nitrate supplementation. A tendency for a quadratic effect (P = 0.10) of the dosage of maternal dietary nitrate was found on preweaning mortality of piglets with the lowest level of mortality found at 0.09% to 0.12% of maternal nitrate supplementation. We conclude that the use of nitrate in the maternal diet of sows during the perinatal period might stimulate preweaning piglet vitality. Exact mode of action and optimal dose of nitrate still need to be elucidated.
    Effects of maternal dietary nitrate supplementation on farrowing and placental characteristics, level of asphyxiation at birth and piglet vitality
    Bosch, M. van den; Wijnen, H.J. ; Linde, I.B. van der; Wesel, A.A.M. van; Melchior, D. ; Kemp, B. ; Brand, H. van den; Clouard, C.M. - \ 2019
    Theriogenology 129 (2019). - ISSN 0093-691X - p. 1 - 7.
    nitrate - piglet vitality - placenta - farrowing - asphyxiation
    We investigated whether maternal dietary nitrate supplementation, leading to nitric oxide (NO) formation, would affect duration of farrowing, levels of asphyxiation, vitality of piglets at birth and/or loss of potential viable piglets in the form of stillbirth and pre-weaning mortality. Data were collected from 190 crossbred (Yorkshire x Dutch Landrace) sows, which were allocated, balanced for parity, to six dietary nitrate levels (0, 0.03, 0.06, 0.09, 0.12 or 0.15% of nitrate). Sow received the lactational diet containing nitrate from approximately 7 days before farrowing until 5 days after farrowing. Blood acid-base parameters (pH, pO2, pCO2, BEecf, HCO3, sO2 and lactate) and nitrate concentration were determined in umbilical cord blood. The farrowing process was video recorded and later analysed for total duration of farrowing, piglet birth interval, piglet vitality was scored and piglet latency to stand right after birth. Placentas were collected after expulsion during and after farrowing. Placenta length and width were measured and placental color scores were assessed based on redness of the placenta. The probability of a higher vitality score of piglets (being more vital) linearly increased with increasing levels of maternal dietary nitrate. This higher vitality score however, was not reflected by changes in the blood acid-base parameters in umbilical cord blood, except for a tendency for a higher pO2 with increasing levels of nitrate, which could have been caused by a quicker onset of respiration or an increased blood flow to the piglets during birth. Placenta width increased with increasing levels of maternal dietary nitrate, but no effect on placenta length and redness was found. Neither duration of farrowing nor birth interval were affected by maternal dietary nitrate level. In conclusion, maternal nitrate supplementation may affect piglet vitality via vasodilatation (placental characteristics) rather than an increase in exercise efficiency (duration of farrowing).
    Light-dark rhythms during incubation of broiler chicken embryos and their effects on embryonic and post hatch leg bone development
    Pol, C.W. van der; Roovert-Reijrink, Inge Van; Maatjens, C.M. ; Gussekloo, S.W.S. ; Kranenbarg, S. ; Wijnen, H.J. ; Pieters, R.P.M. ; Schipper, H. ; Kemp, B. ; Brand, H. van den - \ 2019
    PLoS ONE (2019). - ISSN 1932-6203 - 17 p.
    There are indications that lighting schedules applied during incubation can affect leg health at hatching and during rearing. The current experiment studied effects of lighting schedule: continuous light (24L), 12 hours of light, followed by 12 hours of darkness (12L:12D), or continuous darkness (24D) throughout incubation of broiler chicken eggs on the development and strength of leg bones, and the role of selected hormones in bone development. In the tibiatarsus and femur, growth and ossification during incubation and size and microstructure at day (D)0, D21, and D35 post hatching were measured. Plasma melatonin, growth hormone, and IGF-I were determined perinatally. Incidence of tibial dyschondroplasia, a leg pathology resulting from poor ossification at the bone’s epiphyseal plates, was determined at slaughter on D35. 24L resulted in lower embryonic ossification at embryonic day (E)13 and E14, and lower femur length, and lower tibiatarsus weight, length, cortical area, second moment of area around the minor axis, and mean cortical thickness at hatching on D0 compared to 12L:12D especially. Results were long term, with lower femur weight and tibiatarsus length, cortical and medullary area of the tibiatarsus, and second moment of area around the minor axis, and a higher incidence of tibial dyschondroplasia for 24L. Growth hormone at D0 was higher for 24D than for 12L:12D, with 24L intermediate, but plasma melatonin and IGF-I did not differ between treatments, and the role of plasma melatonin, IGF-I, and growth hormone in this process was therefore not clear. To conclude, in the current experiment, 24L during incubation of chicken eggs had a detrimental effect on embryonic leg bone development and later life leg bone strength compared to 24D and 12L:12D, while the light-dark rhythm of 12L:12D may have a stimulating effect on leg health.
    Models for assessing engineered nanomaterial fate and behaviour in the aquatic environment
    Williams, Richard J. ; Harrison, Samuel ; Keller, Virginie ; Kuenen, Jeroen ; Lofts, Stephen ; Praetorius, Antonia ; Svendsen, Claus ; Vermeulen, Lucie C. ; Wijnen, Jikke van - \ 2019
    Current Opinion in Environmental Sustainability 36 (2019). - ISSN 1877-3435 - p. 105 - 115.

    Engineered nanomaterials (ENMs, material containing particles with at least one dimension less than 100 nm) are present in a range of consumer products and could be released into the environment from these products during their production, use or end-of-life. The high surface to volume ratio of nanomaterials imparts a high reactivity, which is of interest for novel applications but may raise concern for the environment. In the absence of measurement methods, there is a need for modelling to assess likely concentrations and fate arising from current and future releases. To assess the capability that exists to do such modelling, progress in modelling ENM fate since 2011 is reviewed. ENM-specific processes represented in models are mainly limited to aggregation and, in some instances, dissolution. Transformation processes (e.g. sulphidation), the role of the manufactured coatings, particle size distribution and particle form and state are still usually excluded. Progress is also being made in modelling ENMs at larger scales. Currently, models can give a reasonable assessment of the fate of ENMs in the environment, but a full understanding will likely require fuller inclusion of these ENM-specific processes.

    Global multi-pollutant modelling of water quality: scientific challenges and future directions
    Strokal, M. ; Spanier, Emiel ; Kroeze, C. ; Koelmans, A.A. ; Florke, Martina ; Franssen, W.H.P. ; Hofstra, N. ; Langan, Simon ; Ting, Tang ; Vliet, M.T.H. van; Wada, Yoshihide ; Wang, M. ; Wijnen, Jikke van; Williams, R. - \ 2019
    Current Opinion in Environmental Sustainability 36 (2019). - ISSN 1877-3435 - p. 116 - 125.
    Assessing global water quality issues requires a multi-pollutant modelling approach. We discuss scientific challenges and future directions for such modeling. Multi-pollutant river models need to integrate information on sources of pollutants such as plastic debris, nutrients, chemicals, pathogens, their effects and possible solutions. In this paper, we first explain what we consider multi-pollutant modelling. Second, we discuss scientific challenges in multi-pollutant modelling relating to consistent model inputs, modelling approaches and model evaluation. Next, we illustrate the potential of global multi-pollutant modelling for hotspot analyses. We show hotspots of river pollution with microplastics, nutrients, triclosan and Cryptosporidium in many sub-basins of Europe, North America and South Asia. Finally, we reflect on future directions for multi-pollutant modelling, and for linking model results to policy-making.
    Eggshell temperature pattern during incubation affects leg bone characteristics of broiler chickens at slaughter age
    Molenaar, R. ; Guz, Bahadir ; Wijnen, H.J. ; Krimpen, M.M. van; Jong, I.C. de; Brand, H. van den - \ 2018
    In: Abstracts of the Incubation and Fertility Research Group. - - p. 19 - 19.
    Effect of constant or weekly varied eggshell temperature during incubation on broiler performance up until slaughter age
    Wijnen, H.J. ; Roovert-Reijrink, Inge van; Eijk-Priester, Marieke van; Pol, C. van der; Molenaar, R. ; Brand, H. van den - \ 2018
    In: The XVth European Poultry Conference (EPC). - Zagreb, Croatia : Croatian Branch of the World's Poultry Science Association - ISBN 9789082915709 - p. 498 - 498.
    broiler - eggshell temperature - incubation - performance - compensatory growth - delayed nutrition - early nutrition
    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.
    Applying cold incubation profiles during the last week of incubation in a commercial incubator: effects on broiler embryonic mortality, hatchability, and chick quality
    Roovert, Inge van; Eijk-Priester, Marieke van; Wijnen, H.J. ; Pol, C. van der - \ 2018
    In: The XVth European Poultry Conference (EPC). - Zagreb, Croatia : Croatian Branch of the World's Poultry Science Association - ISBN 9789082915709 - p. 126 - 126.
    chick quality - eggshell temperature - hatchability - incubation
    During incubation, an eggshell temperature (EST, as a reflection of embryo temperature) of 37.8°C was long considered to be optimal for broiler embryonic development. However, an EST of 36.7°C (Cold) from embryonic day (E)15 onward may result in a more developed heart at hatching than 37.8°C EST throughout (Control; Maatjens et al., 2016). Maatjens et al.’s study was performed in large incubation chambers with low air velocity, unlike commercial practice. To study Cold EST in a commercial situation with high air velocity and egg density, three trials were conducted. In all trials, EST for Cold was maintained at 37.8°C, decreased to 36.7°C with varying profiles in the last week, and then maintained at 36.7°C till hatching. Cold treatments were always compared to Control (37.8°C EST throughout incubation). 3,000-10,800 broiler eggs from a 30-39 week old parent flock were used. Firstly, EST was decreased within 30 minutes, on E15. Compared to Control, Cold resulted in 2.5x higher embryonic mortality around the time of the EST decrease (P = 0.015), 2.2% more second grade chicks (P = 0.049), and chicks were 0.4cm shorter (indicating lower development) at hatch (P = 0.001). Possibly, the EST decrease happened too early or abruptly. Secondly, EST was decreased gradually in 1 day, from E16-E17. No differences were found in hatchability (P = 0.68) or chick length (P = 0.93), but embryonic mortality around the time of the EST decrease tended to be 1.7x higher for Cold than for Control (P = 0.070). It was thought that an even slower EST decrease may optimize Cold further. Thirdly, EST was decreased using three different profiles. EST was decreased gradually from E16-E17, or quickly (to 36.9°C on E17) and then slowly (to 36.7°C on E18), or slowly (to 37.5°C on E17) and then quickly (to 36.7°C on E18). Embryonic mortality, hatchability, and navel quality did not differ between the Cold profiles and Control (P > 0.29). To conclude, results differed from the low air velocity trial situation. When EST was decreased from 37.8°C to 36.7°C abruptly or too early in development, hatchability and chick quality decreased. A slow transition from E16-E18 can result in chick quality and hatchability similar to Control. Knowledge on these optimal EST decrease profiles can be used to further investigate the effect of Cold incubation during the last days of incubation on post hatch performance and possibly apply it to commercial practice.
    The effect of different eggshell temperature patterns during incubation on broiler chicken behavior determined by an automatic tracking system
    Molenaar, R. ; Haas, E.N. de; Rodenburg, T.B. ; Olde Bolhaar, Lara ; Wijnen, H.J. ; Brand, H. van den - \ 2018
    In: The XVth European Poultry Conference (EPC). - Zagreb, Croatia : Croatian Branch of the World's Poultry Science Association - ISBN 9789082915709 - p. 248 - 248.
    behaviour - broiler chicken - incubation - tracking - compensatory growth - delayed nutrition - early nutrition

    Effect of constant or weekly varied eggshell temperature during incubation on broiler performance up until slaughter age
    Wijnen, H.J. ; Roovert-Reijrink, Inge Van; Priester, Marieke ; Pol, C.W. van der; Molenaar, R. ; Brand, H. van den - \ 2018
    broiler - eggshell temperature - incubation - performance - compensatory growth - delayed nutrition - early nutrition
    During incubation, embryo development is particularly influenced by temperature. Thevast majority of commercial hatcheries aim at a constant eggshell temperature (EST) of37.8°C throughout incubation. However, it has been shown recently that lowering EST(36.7°C) in the last week of incubation might improve embryo development, as higher(yolk-free) body mass and relative organ weights at hatch were found. In addition,raising EST slightly in phases during which oxygen is not limited yet (before the lastweek of incubation), might improve embryo development as well. It is hypothesizedthat a lower EST (36.7°) in the last week of incubation and a higher EST (38.9°C) in thesecond week of incubation improve embryo development and perinatal chick qualitycompared to a constant intermediate EST (37.6°) throughout incubation. Moreover,EST during incubation might have long term effects on broiler performance as theincubation period covers a substantial part of their whole lifespan and as it is knownfor many animal species that perinatal experiences have an impact in later life. Totest this hypothesis, Ross 308 eggs from a prime parent flock were incubated in a 2x2experimental design. All eggs were incubated at a normal (37.8°C) EST until embryonicday (E) 7. Thereafter, eggs were either incubated at a normal (37.8°C) or high (38.9°C)EST during the second week (E7 – E14) of incubation and a normal (37.8°C) or low(36.7°C) EST during the last week (E14 – E21) of incubation. Within 6 hours afterhatch, chick development was evaluated by chick weight, length, navelscore, and organweights. Posthatch, 5 males and 5 females were housed in a 2 m2 pen with 8 replicatesper treatment (n=320) and reared until slaughter age (D42). Growth and feed intakewere monitored weekly. At D28, D35, and D39 gait was scored from all animals. Atslaughter, foot-pad dermatitis, hock burns, and carcass characteristics were determined.Preliminary results indicate that a low EST from E15 onwards results in slower growthand on average 103 g. lower body weight at slaughter. Other parameters were notsignificantly different or not analysed yet (e.g. carcass characteristics) at the moment ofabstract submission.
    Fast increases in river pollution from sewage: a global trend
    Strokal, M. ; Kroeze, C. ; Franssen, W.H.P. ; Hofstra, N. ; Koelmans, A.A. ; Siegfried, Max ; Vliet, M.T.H. van; Wijnen, Jikke van; Vermeulen, L.C. - \ 2018
    Geophysical Research Abstracts 20 (2018). - ISSN 1029-7006 - 1 p.
    River export of triclosan from land to sea : A global modelling approach
    Wijnen, Jikke van; Ragas, Ad M.J. ; Kroeze, Carolien - \ 2018
    Science of the Total Environment 621 (2018). - ISSN 0048-9697 - p. 1280 - 1288.
    Coastal areas - Future scenarios - Global TCS model - River pollution - Triclosan
    Triclosan (TCS) is an antibacterial agent that is added to commonly used personal care products. Emitted to the aquatic environment in large quantities, it poses a potential threat to aquatic organisms. Triclosan enters the aquatic environment mainly through sewage effluent. We developed a global, spatially explicit model, the Global TCS model, to simulate triclosan transport by rivers to coastal areas. With this model we analysed annual, basin-wide triclosan export for the year 2000 and two future scenarios for the year 2050. Our analyses for 2000 indicate that triclosan export to coastal areas in Western Europe, Southeast Asia and the East Coast of the USA is higher than in the rest of the world. For future scenarios, the Global TCS model predicts an increase in river export of triclosan in Southeast Asia and a small decrease in Europe. The number of rivers with an annual average triclosan concentration at the river mouth that exceeds a PNEC of 26.2. ng/L is projected to double between 2000 and 2050. This increase is most prominent in Southeast Asia, as a result of fast population growth, increasing urbanisation and increasing numbers of people connected to sewerage systems with poor wastewater treatment. Predicted triclosan loads correspond reasonably well with measured values. However, basin-specific predictions have considerable uncertainty due to lacking knowledge and location-specific data on the processes determining the fate of triclosan in river water, e.g. sorption, degradation and sedimentation. Additional research on the fate of triclosan in river systems is therefore recommended. Capsule: We developed a global spatially explicit model to simulate triclosan export by rivers to coastal seas. For two future scenarios this Global TCS model projects an increase in river export of triclosan to several seas around the world.
    Food For Mars and Moon op Lowlands
    Wamelink, G.W.W. - \ 2017
    Wageningen : Wageningen University & Research
    Wij, Joep en ik, hadden er al weken naar uitgekeken, het optreden in de wetenschapstent van Lowlands. Een interview van een klein uur in het kader van het VPRO programma ‘The universe of the mind’ samen met aspirant astronaut Thomas Wijnen. Helaas was Robbert Dijkgraaf er niet, maar Rob van Hattem en Jim Jansen zorgden voor levendige vragen en een goede interactie met het publiek.
    Data from: Cascading effects of predator activity on tick-borne disease risk
    Hofmeester, T.R. ; Jansen, P.A. ; Wijnen, H.J. ; Coipan, E.C. ; Fonville, Manoj ; Prins, H.H.T. ; Sprong, Hein ; Wieren, S.E. van - \ 2017
    Wageningen University & Research
    Borrelia burgdorferi - predators - carnivores - rodents
    Predators and competitors of vertebrates can in theory reduce the density of infected nymphs (DIN)—an often-used measure of tick-borne disease risk—by lowering the density of reservoir-competent hosts and/or the tick burden on reservoir-competent hosts. We investigated this possible indirect effect of predators by comparing data from 20 forest plots across the Netherlands that varied in predator abundance. In each plot, we measured the density of questing Ixodes ricinus nymphs (DON), DIN for three pathogens, rodent density, the tick burden on rodents and the activity of mammalian predators. We analysed whether rodent density and tick burden on rodents were correlated with predator activity, and how rodent density and tick burden predicted DON and DIN for the three pathogens. We found that larval burden on two rodent species decreased with activity of two predator species, while DON and DIN for all three pathogens increased with larval burden on rodents, as predicted. Path analyses supported an indirect negative correlation of activity of both predator species with DON and DIN. Our results suggest that predators can indeed lower the number of ticks feeding on reservoir-competent hosts, which implies that changes in predator abundance may have cascading effects on tick-borne disease risk.
    Affecting leg bone development in broiler chickens through incubation lighting schedules
    Pol, C.W. van der; Roovert-Reijrink, Inge Van; Priester, Marieke ; Wijnen, H.J. ; Brand, H. van den - \ 2017
    European Poultry Science 81 (2017). - ISSN 1612-9199 - p. 25 - 25.
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