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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    Carbon-nitrogen interactions in European forests and semi-natural vegetation - Part 1 : Fluxes and budgets of carbon, nitrogen and greenhouse gases from ecosystem monitoring and modelling
    Sutton, Mark A. ; Flechard, Chris R. ; Ibrom, Andreas ; Skiba, Ute M. ; Vries, Wim De; Oijen, Marcel Van; Cameron, David R. ; DIse, Nancy B. ; Korhonen, Janne F.J. ; Buchmann, Nina ; Legout, Arnaud ; Simpson, David ; Sanz, Maria J. ; Aubinet, Marc ; Loustau, Denis ; Montagnani, Leonardo ; Neirynck, Johan ; Janssens, Ivan A. ; Pihlatie, Mari ; Kiese, Ralf ; Siemens, Jan ; Francez, Andre Jean ; Augustin, Jurgen ; Varlagin, Andrej ; Olejnik, Janusz ; Juszczak, Radoslaw ; Aurela, Mika ; Berveiller, Daniel ; Chojnicki, Bogdan H. ; Dämmgen, Ulrich ; Delpierre, Nicolas ; Djuricic, Vesna ; Drewer, Julia ; Dufrêne, Eric ; Eugster, Werner ; Fauvel, Yannick ; Fowler, David ; Frumau, Arnoud ; Granier, André ; Gross, Patrick ; Hamon, Yannick ; Helfter, Carole ; Hensen, Arjan ; Horvath, Laszlo ; Kitzler, Barbara ; Kruijt, Bart ; Kutsch, Werner L. ; Lobo-Do-Vale, Raquel ; Lohila, Annalea ; Longdoz, Bernard ; Marek, Michal V. ; Matteucci, Giorgio ; Mitosinkova, Marta ; Moreaux, Virginie ; Neftel, Albrecht ; Ourcival, Jean Marc ; Pilegaard, Kim ; Pita, Gabriel ; Sanz, Francisco ; Schjoerring, Jan K. ; Sebastià, Maria Teresa ; Sim Tang, Y. ; Uggerud, Hilde ; Urbaniak, Marek ; DIjk, Netty Van; Vesala, Timo ; Vidic, Sonja ; Vincke, Caroline ; Weidinger, Tamas ; Zechmeister-Boltenstern, Sophie ; Butterbach-Bahl, Klaus ; Nemitz, Eiko - \ 2020
    Biogeosciences 17 (2020)6. - ISSN 1726-4170 - p. 1583 - 1620.

    The impact of atmospheric reactive nitrogen (Nr) deposition on carbon (C) sequestration in soils and biomass of unfertilized, natural, semi-natural and forest ecosystems has been much debated. Many previous results of this dC=dN response were based on changes in carbon stocks from periodical soil and ecosystem inventories, associated with estimates of Nr deposition obtained from large-scale chemical transport models. This study and a companion paper (Flechard et al., 2020) strive to reduce uncertainties of N effects on C sequestration by linking multi-annual gross and net ecosystem productivity estimates from 40 eddy covariance flux towers across Europe to local measurement-based estimates of dry and wet Nr deposition from a dedicated collocated monitoring network. To identify possible ecological drivers and processes affecting the interplay between C and Nr inputs and losses, these data were also combined with in situ flux measurements of NO, N2O and CH4 fluxes; soil NO3 leaching sampling; and results of soil incubation experiments for N and greenhouse gas (GHG) emissions, as well as surveys of available data from online databases and from the literature, together with forest ecosystem (BASFOR) modelling. Multi-year averages of net ecosystem productivity (NEP) in forests ranged from 70 to 826 gCm2 yr1 at total wetCdry inorganic Nr deposition rates (Ndep) of 0.3 to 4.3 gNm2 yr1 and from 4 to 361 g Cm2 yr1 at Ndep rates of 0.1 to 3.1 gNm2 yr1 in short semi-natural vegetation (moorlands, wetlands and unfertilized extensively managed grasslands). The GHG budgets of the forests were strongly dominated by CO2 exchange, while CH4 and N2O exchange comprised a larger proportion of the GHG balance in short semi-natural vegetation. Uncertainties in elemental budgets were much larger for nitrogen than carbon, especially at sites with elevated Ndep where Nr leaching losses were also very large, and compounded by the lack of reliable data on organic nitrogen and N2 losses by denitrification. Nitrogen losses in the form of NO, N2O and especially NO3 were on average 27%(range 6 % 54 %) of Ndep at sites with Ndep < 1 gNm2 yr1 versus 65% (range 35 % 85 %) for Ndep > 3 gNm2 yr1. Such large levels of Nr loss likely indicate that different stages of N saturation occurred at a number of sites. The joint analysis of the C and N budgets provided further hints that N saturation could be detected in altered patterns of forest growth. Net ecosystem productivity increased with Nr deposition up to 2 2.5 gNm2 yr1, with large scatter associated with a wide range in carbon sequestration efficiency (CSE, defined as the NEP = GPP ratio). At elevated Ndep levels (> 2.5 gNm2 yr1), where inorganic Nr losses were also increasingly large, NEP levelled off and then decreased. The apparent increase in NEP at low to intermediate Ndep levels was partly the result of geographical cross-correlations between Ndep and climate, indicating that the actual mean dC=dN response at individual sites was significantly lower than would be suggested by a simple, straightforward regression of NEP vs. Ndep.

    Diet density during the first week of life: Effects on growth performance, digestive organ weight, and nutrient digestion of broiler chickens
    Lamot, D.M. ; Sapkota, D. ; Wijtten, P.J.A. ; Anker-Hensen, I. van den; Heetkamp, M.J.W. ; Kemp, B. ; Brand, H. van den - \ 2019
    Poultry Science 98 (2019)2. - ISSN 0032-5791 - p. 789 - 795.
    The current study aimed to investigate whether diet density affects growth performance and nutrient digestion during the first wk after hatch and digestive organ weight at 7 d of age. Effects were studied using a dose-response design consisting of 5 dietary fat levels (3.5, 7.0, 10.5, 14.0, and 17.5%). The dietary fat level was increased through soybean oil inclusion. Amino acids, minerals, and the premix were increased at the same ratio as dietary fat. Consequently, diets were kept neither isocaloric nor isonitrogenous. Broiler chickens were weighed on d 0 and d 7 after hatch, whereas feed intake was measured daily. Excreta produced from d 0 to d 7 was collected at d 7. Dietary dry matter and nitrogen metabolizability, as well as fat digestibility were calculated as an average over 7 days. Broiler chickens were sampled at d 7 to determine carcass yield, breast meat yield, and organ weights. Average daily gain (P = 0.047) and average daily feed intake (P < 0.001) decreased linearly as diet density increased, while gain to feed ratio increased linearly (P < 0.001). An increased diet density resulted in a linear decrease of crop, liver, and pancreas weight relative to body weight (BW; P < 0.05). Duodenum, jejunum, ileum, and cecum length (expressed as cm/kg of BW) and empty weight (as % of BW) increased linearly with increased diet density (P < 0.05). Dietary dry matter metabolizability decreased linearly as diet density increased (P < 0.001), whereas fat digestibility and nitrogen metabolizability were not affected (P > 0.05). In conclusion, one-week-old broiler chickens respond to increased diet densities by increasing intestinal weight and length, while decreasing liver and pancreas weight. This may be an adaptive response to cope with an increased nutrient concentration in the diet.
    Both the rooster line and incubation temperature affect embryonic metabolism and hatchling quality in laying hen crossbreds
    Brand, H. van den; Kraats, S.J.F. van de; Sözcü, Arda ; Jöerissen, R. ; Heetkamp, M.J.W. ; Anker-Hensen, I. van den; Ooms, M. ; Kemp, B. - \ 2019
    Poultry Science 98 (2019)6. - ISSN 0032-5791 - p. 2632 - 2640.
    Effects of 3 eggshell temperatures (EST; 36.7. 37.8, and 38.9°C) in 2 genetic laying hen crossbreds (AB and BB; same hen line, different rooster line) on embryonic metabolism and hatchling quality were investigated. EST were applied from day 14.5 of incubation (E14.5) until hatching. The experiment consisted of 6 consecutive batches with eggs weighing between 59 and 61 g. Heat production was determined continuously from E14.5 onward. In fresh eggs, yolk weight tended to be higher (Δ = 0.28 g; P = 0.08) in the AB crossbred than in the BB crossbred. At E14.5 and E18.5, yolk-free body mass (YFBM) and residual yolk (RY) weight did not differ between genetic crossbred and EST. Hatching time after the start of incubation was not affected by genetic crossbred, but was longer in the 36.7°C (517 h) than in the 38.9°C (505 h), with 37.8°C in between (506 h). At 6 h after hatching, no differences between crossbreds were found for chicken quality parameters, such as chicken weight, chicken length, RY, YFBM, and organ weights, but heart weight was higher in the 36.7°C EST than in the other 2 EST (Δ = 0.24 to 0.30% of YFBM, P = 0.005). Intestinal weight was higher at 36.7°C EST than at 38.9°C EST (Δ = 0.79% of YFBM; P = 0.02), with 37.8°C EST in between. Heat production between E14.5 and E18.5 was higher in the AB crossbred than in the BB crossbred (Δ = 2.61%, P < 0.001) and regardless of crossbred higher at an EST of 38.9°C than at other 2 EST (Δ = 3.59% on average; P < 0.001). Hatchling quality determined at pulling (E21.5) was not affected by EST, but AB chickens were lighter (Δ = 0.46 g; P = 0.03), had less red hocks (Δ = 0.03; P = 0.02), more red beaks (Δ = 0.10; P < 0.001), and a higher (worse) navel score (Δ = 0.11; P < 0.001) than BB chickens. It can be concluded that not only incubation temperature, but also the rooster line appears to play a role in layer crossbred embryo metabolism and hatchling quality.
    Both the rooster and incubation temperature affect embryonic metabolism and day-old chicken quality in laying hens
    Brand, H. van den; Kraats, Sabrina van de; Sözcü, Arda ; Jöerissen, R. ; Heetkamp, M.J.W. ; Anker-Hensen, I. van den; Ooms, M. ; Kemp, B. - \ 2018
    In: The XVth European Poultry Conference (EPC). - Zagreb, Croatia : Croatian Branch of the World's Poultry Science Association - ISBN 9789082915709 - p. 128 - 128.
    chicken quality - embryonic heat production - incubation temperature - laying hens - rooster
    During incubation, the main factors driving embryonic metabolism and developmentare nutrient availability, oxygen availability and embryo temperature. Both nutrient andoxygen availability are expected to be particularly affected by the hen and thus the henis thought to majorly determining embryonic metabolism and day-old chicken quality.However, in wild birds it has been suggested that the rooster is of influence on offspringquality, directly or via affecting egg size and egg composition. In poultry, the role of therooster in embryonic development and metabolism is hardly investigated. In case therooster affects egg composition, this can mean that the incubation temperature needs to be adjusted to obtain optimal embryo temperature. The role of incubation temperatureon embryonic metabolism and development in the broiler chicken is extensivelyinvestigated, but much less information is available regarding laying hen chickens.The aim of the experiment was to investigate the role of the rooster and the incubationtemperature on laying hen embryonic development and chicken quality. Eggs of twogenetic crossbreds (AB and BB; 51 to 59 weeks of age) were used. Hens originated fromthe same breeder flock, were housed at the same farm, obtained the same managementand diet but were mated with a different rooster. In six consecutive batches, eggs ofboth crossbreds (59.0 to 61.0 gram) were incubated at an eggshell temperature (EST) of37.8oC during the first 14.5 days and at an EST of 36.7, 37.8 or 38.9oC from day 14.5 ofincubation onward. In all batches, eggs of both crossbreds were used, but EST differedamong batches. Egg composition was determined in fresh eggs, heat production wasdetermined between day 14.5 and 18.5 of incubation and day-old chicken quality wasdetermined at 6 hours after hatching or at pulling. Yolk weight tended to be higher(Δ=0.28 gram; P=0.08) in AB than in BB crossbreds, whereas other egg components didnot differ. Heat production between day 14.5 and 18.5 of incubation was higher in theAB than in the BB crossbred (Δ=2.61%; P<0.001). At pulling, AB chickens were lighter,had less red hocks, more red beaks and worse navel scores than BB chickens. An ESTof 36.7oC resulted in later hatching time, higher heart weight and higher intestineweight than an EST of 38.9oC. It can be concluded that both the rooster and incubationtemperature appears to affect embryonic metabolism and day-old chicken quality.
    Effects of breeder age and oxygen concentration during incubation on embryonic heat production and development, and post-hatch chick performance
    Molenaar, R. ; Nangsuay, A. ; Meijerhof, R. ; Anker-Hensen, I. van den; Heetkamp, M.J.W. ; Kemp, B. ; Brand, H. van den - \ 2017
    European Poultry Science 81 (2017). - ISSN 1612-9199 - p. 4 - 4.
    The interaction between carbon dioxide concentration and eggshell temperature during the second half of incubation in broiler chickens
    Brand, H. van den; Meijerhof, R. ; Heetkamp, M.J.W. ; Anker-Hensen, I. van den; Ooms, M. ; Kemp, B. - \ 2017
    European Poultry Science 81 (2017). - ISSN 1612-9199 - p. 23 - 23.
    Poultry - CO2 - eggshell - heat production - chicken quality
    The effects of temperature during late incubation on first week broiler chicken development
    Maatjens, C.M. ; Roovert-Reijrink, Inge A.M. van; Anker-Hensen, I. van den; Engel, Bastiaan ; Pol, C.W. van der; Kemp, B. ; Brand, H. van den - \ 2017
    European Poultry Science 81 (2017). - ISSN 1612-9199 - p. 24 - 24.
    A multi-model approach to monitor emissions of CO2 and CO from an urban–industrial complex
    Super, I. ; Denier van der Gon, H.A.C. ; Molen, M.K. van der; Sterk, H.A.M. ; Hensen, A. ; Peters, W. - \ 2017
    Atmospheric Chemistry and Physics 17 (2017). - ISSN 1680-7316 - p. 13297 - 13316.
    Monitoring urban–industrial emissions is often challenging because observations are scarce and regional atmospheric transport models are too coarse to represent the high spatiotemporal variability in the resulting concentrations.
    In this paper we apply a new combination of an Eulerian model (Weather Research and Forecast, WRF, with chemistry) and a Gaussian plume model (Operational Priority Substances – OPS). The modelled mixing ratios are compared to observed CO2 and CO mole fractions at four sites along a transect from an urban–industrial complex (Rotterdam, the Netherlands) towards rural conditions for
    October–December 2014. Urban plumes are well-mixed at our semi-urban location, making this location suited for an integrated emission estimate over the whole study area. The signals at our urban measurement site (with average enhancements of 11 ppm CO2 and 40 ppb CO over the baseline) are highly variable due to the presence of distinct source areas dominated by road traffic/residential heating emissions or industrial activities. This causes different emission signatures that are translated into a large variability in observed
    1COV1CO2 ratios, which can be used to identify dominant source types. We find that WRF-Chem is able to represent synoptic variability in CO2 and CO (e.g. the median CO2 mixing ratio is 9.7 ppm, observed, against 8.8 ppm, modelled),
    but it fails to reproduce the hourly variability of daytime urban plumes at the urban site (R2 up to 0.05). For the urban site, adding a plume model to the model framework is beneficial to adequately represent plume transport especially
    from stack emissions. The explained variance in hourly, daytime CO2 enhancements from point source emissions increases from 30% with WRF-Chem to 52% with WRFChem in combination with the most detailed OPS simulation.
    The simulated variability in 1COV1CO2 ratios decreases drastically from 1.5 to 0.6 ppbppm􀀀1, which agrees better with the observed standard deviation of 0.4 ppbppm􀀀1. This is partly due to improved wind fields (increase in R2 of 0.10) but also due to improved point source representation (increase in R2 of 0.05) and dilution (increase in R2 of 0.07). Based on our analysis we conclude that a plume model with detailed and accurate dispersion parameters adds substantially to top–down monitoring of greenhouse gas emissions in urban environments with large point source contributions within a 10 km radius from the observation sites.
    Diet density during the first week of life: Effects on energy and nitrogen balance characteristics of broiler chickens
    Lamot, D.M. ; Sapkota, D. ; Wijtten, P.J.A. ; Anker-Hensen, I. van den; Heetkamp, M.J.W. ; Kemp, B. ; Brand, H. van den - \ 2017
    Poultry Science 96 (2017)7. - ISSN 0032-5791 - p. 2294 - 2300.
    broiler chickens - dietary fat - diet density - energy balance - indirect calorimetry
    This study aimed to determine effects of diet density on growth performance, energy balance, and nitrogen (N) balance characteristics of broiler chickens during the first wk of life. Effects of diet density were studied using a dose-response design consisting of 5 dietary fat levels (3.5, 7.0, 10.5, 14.0, and 17.5%). The relative difference in dietary energy level was used to increase amino acid levels, mineral levels, and the premix inclusion level at the same ratio. Chickens were housed in open-circuit climate respiration chambers from d 0 to 7 after hatch. Body weight was measured on d 0 and 7, whereas feed intake was determined daily. For calculation of energy balances, O2 and CO2 exchange were measured continuously and all excreta from d 0 to 7 was collected and analyzed at d 7. Average daily gain (ADG) and average daily feed intake (ADFI) decreased linearly (P = 0.047 and P < 0.001, respectively), whereas gain to feed ratio increased (P < 0.001) with increasing diet density. Gross energy (GE) intake and metabolizable energy (ME) intake were not affected by diet density, but the ratio between ME and GE intake decreased linearly with increasing diet density (P = 0.006). Fat, N, and GE efficiencies (expressed as gain per unit of nutrient intake), heat production, and respiratory exchange ratio (CO2 to O2 ratio) decreased linearly (P < 0.001) as diet density increased. Energy retention, N intake, and N retention were not affected by diet density. We conclude that a higher diet density in the first wk of life of broiler chickens did not affect protein and fat retention, whereas the ME to GE ratio decreased linearly with increased diet density. This suggests that diet density appears to affect digestibility rather than utilization of nutrients.
    Effects of breeder age, strain, and eggshell temperature on nutrient metabolism of broiler embryos
    Nangsuay, A. ; Meijerhof, R. ; Anker-Hensen, I. van den; Heetkamp, M.J.W. ; Kemp, B. ; Brand, H. van den - \ 2017
    Poultry Science 96 (2017)1. - ISSN 0032-5791 - p. 1891 - 1900.
    Breeder age and broiler strain influence the availability of nutrients and oxygen through yolk size and eggshell conductance, and the effects of these egg characteristics on nutrient metabolism might be influenced by eggshell temperature (EST). This study aims to determine effects of breeder age, strain, and EST on nutrient metabolism of embryos. A study was designed as a 2 × 2 × 2 factorial arrangement using four batches of in total 4,464 hatching eggs of 2 flock ages at 29 to 30 wk (young) and 54 to 55 wk (old) of Ross 308 and Cobb 500. EST of 37.8 (normal) or 38.9°C (high) was applied from incubation day 7 (E7) until hatching. Wet yolk weight was determined mainly by breeder age (P = 0.043). Energy content in yolk (P = 0.004) and albumen + yolk (P = 0.005) were higher in old flock eggs than in young flock eggs, but did not differ between broiler strains. Eggshell conductance was higher in Ross 308 eggs than in Cobb 500 eggs (P < 0.001). Old flock embryos used more energy (P = 0.046) and accumulated more energy into yolk free body mass (YFBM; P = 0.030) than young flock embryos, whereas heat production (HP), energy lost, and efficiency of converting energy used to YFBM (EYFB) did not differ. Ross 308 embryos used more energy (P = 0.006), had a higher energy lost (P = 0.010), and a higher HP between E15 to E18 (P < 0.05) than Cobb 500 embryos. Energy content in YFBM did not differ between strains and EYFB (P = 0.024) was lower in Ross 308 than in Cobb 500. High EST resulted in higher HP than low EST from E11 to E15 (P < 0.05), but not after E15. Amount of energy used (P = 0.006) and energy accumulated in the YFBM (P < 0.001) was lower for embryos incubated at an EST of 38.9 than that of 37.8°C, whereas EYFB did not differ. In conclusion, breeder age, broiler strain, and EST differentially influence embryonic metabolism and particularly the availability of oxygen could have contributed to these differences.
    Effects of increased diet density through increased dietary fat level on energy balance characteristics of broilers during the first week of life
    Lamot, D.M. ; Sapkota, D. ; Wijtten, P.J.A. ; Anker-Hensen, I. van den; Heetkamp, M.J.W. ; Kemp, B. ; Brand, H. van den - \ 2016
    In: Energy and protein metabolism and nutrition. - Wageningen : Wageningen Academic Publishers (EAAP publication 137) - ISBN 9789086862863 - p. 305 - 306.
    The current study aimed to determine the effect of increased diet density through increasing dietary fat level on growth performance and energy balance characteristics of broiler chickens during the first week of life. The effects of diet density on energy and nitrogen metabolism were studied using a dose response design that comprised 5 dietary fat inclusion levels (3.5, 7.0, 10.5, 14.0, and 17.0%) while maintaining a constant digestible amino acid to energy ratio. Chickens were housed in open circuit climate respiration chambers. Preplanned contrasts were used to determine significant linear and quadratic relationships with diet density. Feed intake and BW gain linearly decreased and gain to feed ratio increased (P<0.001) with increasing dietary density. Nutrient efficiencies (calculated as gain per unit of nutrient consumed) for fat, nitrogen and gross energy linearly decreased (P<0.001). A linear decrease in heat production and the respiratory exchange ratio (CO2/O2) were found with increasing diet density (P<0.001). Protein intake and total energy, fat and protein retention were not affected by diet density. To conclude: increased diet density during the first week of age resulted in improved feed efficiency, but not nutrient efficiency. Protein and fat deposition in the body of broilers was similar.
    Effects of increased diet density through increased dietary fat level on growth performance, organ size, and dietary fat metabolizability of broilers during the first week of life
    Lamot, D.M. ; Sapkota, D. ; Wijtten, P.J.A. ; Anker-Hensen, I. van den; Heetkamp, M.J.W. ; Kemp, B. ; Brand, H. van den - \ 2016
    - p. 204 - 204.
    Temperature during the last week of incubation. II. Effects on first week broiler development and performance
    Maatjens, C.M. ; Roovert-Reijrink, Inge Van; Anker-Hensen, I. van den; Engel, Bastiaan ; Pol, C.W. van der; Kemp, B. ; Brand, H. van den - \ 2016
    Poultry Science 95 (2016)9. - ISSN 0032-5791 - p. 2136 - 2144.
    Little is known about applying various eggshell temperatures (EST) during the last week of incubation. In particular, the effect of an EST below 37.8◦C during the last week of incubation is poorly investigated. Therefore, we investigated effects of EST of 35.6, 36.7, 37.8, or 38.9◦C applied from d of incubation (E) 15, E17, or E19 on first week broiler development and performance. A total of, 850 first grade eggs of a 43 wk old Ross 308 broiler breeder flock were incubated at an EST of 37.8◦C until E15. From E15, E17, or E19 onward, eggs were incubated at an EST of 35.6, 36.7, 37.8, or 38.9◦C. Chick quality was determined at placement in the broiler house and organ development was measured at d 7. BW was determined at placement, d4, and d7. Feed intake (FI) was measured at d4 and d7 and G:F was calculated between placement and d4, and between d4 and d7. Chick quality at placement was higher at an EST of 35.6◦C compared to all other EST treatments, expressed by a longer chick length and highest prevalence of closed navels. BW d 7 was higher at an EST of 36.7◦C compared to all other EST treatments, which was not caused by a higher FI during the first week. A higher G:F between d 0 and d 7 was found at an EST of 36.7◦C compared to 35.6 and 38.9◦C. At d 7,
    a higher relative heart weight was found at an EST of 35.6 compared to 38.9◦C. This study indicates that an EST of 38.9◦C applied from E15 onward negatively affected chick quality, organ development, and G:F until d 7 compared to 37.8◦C. Moreover, an EST of 36.7◦C had a clear positive effect on chick quality, organ development, G:F, and growth performance until d 7. An EST of 35.6◦C resulted in equal or higher chick quality and organ weights compared to 36.7◦C, but this was not reflected in performance parameters.
    Embryonic development and heat production
    Nangsuay, A. ; Meijerhof, R. ; Anker-Hensen, I. van den; Heetkamp, M.J.W. ; Kemp, B. ; Brand, H. van den - \ 2016
    International Hatchery Practice 30 (2016)3. - ISSN 0959-9363 - p. 17 - 17.
    Effects of breeder age, broiler strain, and eggshell temperature on development and physiological status of embryos and hatchlings
    Nangsuay, A. ; Meijerhof, R. ; Anker-Hensen, Ilona van den; Heetkamp, M.J.W. ; Souza Morita, V. De; Kemp, B. ; Brand, H. Van Den - \ 2016
    Poultry Science 95 (2016)7. - ISSN 0032-5791 - p. 1666 - 1679.
    Breeder age - Broiler strain - Eggshell temperature - Embryonic development

    Breeder age and broiler strain can influence the availability of nutrients and oxygen, particularly through differences in yolk size and shell conductance. We hypothesized that these egg characteristics might affect embryonic responses to changes in eggshell temperature (EST). This study aimed to investigate the effect of breeder age, broiler strain, and EST on development and physiological status of embryos. A study was designed as a 2 × 2 × 2 factorial arrangement using 4 batches of 1,116 hatching eggs of 2 flock ages at 29 to 30 wk (young) and 54 to 55 wk (old) of Ross 308 and Cobb 500. EST of 37.8 (normal) or 38.9°C (high) was applied from incubation d 7 (E7) until hatching. The results showed that breeder age rather than broiler strain had an influence on yolk size (P = 0.043). The shell conductance was higher in Ross 308 than in Cobb 500 (P <0.001). A high EST resulted in a higher yolk free body mass (YFBM) compared to the normal EST at E14 and E16, but at 3 h after hatch YFBM was lower when eggs were incubated at high EST compared to normal EST (all P <0.001). Cobb 500 eggs yielded embryos with a lower YFBM at E14, E18, and 3 h after hatch (all P <0.05) than Ross 308 eggs. Breeder age had no effect on YFBM, but the RSY weight was higher in embryos from the old flock compared to the young flock embryos at E14 and E16 (both P <0.05). A 3-way interaction among breeder age, strain, and EST was found, especially for incubation duration, navel quality, and relative heart and stomach weights at 3 h after hatch (all P <0.05). Based on the results obtained, we conclude that oxygen availability rather than nutrient availability determines embryonic development, and the egg characteristics affected embryonic responses to changes of EST, especially for variables related to chick quality.

    New bird records for the Island of St. Eustatius, Dutch Caribbean, with notes on other significant sightings
    Madden, H. ; Hensen, Roberto ; Piontek, S. ; Walton, Steffan ; Verdaat, J.P. ; Geelhoed, S.C.V. ; Stapel, J. ; Debrot, A.O. - \ 2015
    The Journal of Caribbean Ornithology 28 (2015). - ISSN 1544-4953 - p. 28 - 34.
    avifauna - Dutch Caribbean - Netherlands Antilles - St. Eustatius
    The avifauna of the Dutch Caribbean island of St. Eustatius has been little studied. We document 22 new bird species for the island and update the status of several important species based on our recent observations. The documented avifauna of
    the island amounts to 75 published species records. We conclude by pointing out several positive developments in the avifauna and ascribe these to the combined effects of reduced hunting, the legal establishment of protected park areas, and a growing environmental awareness among the island’s inhabitants
    Embryonic development and heat production of embryos from two modern broiler strains
    Nangsuay, A. ; Meijerhof, R. ; Anker-Hensen, I. van den; Heetkamp, M.J.W. ; Kemp, B. ; Brand, H. van den - \ 2015
    In: Abstract Book of the 2015 IFRG meeting and 7th Combined Workshop on Fundamental Physiology and Perinatal Development in Poultry. - Berlin, Germany : - p. 37 - 37.
    Corrigendum to : Agricultural peatlands: Towards a greenhouse gas sink - A synthesis of a Dutch landscape study
    Schrier-Uijl, A.P. ; Kroon, P.S. ; Hendriks, D.M.D. ; Hensen, A. ; Huissteden, J. van; Leffelaar, P.A. ; Berendse, F. ; Veenendaal, E.M. - \ 2014
    Biogeosciences 11 (2014). - ISSN 1726-4170 - p. 4635 - 4635.
    Evaluating the performance of commonly used gas analysers for methane eddy covariance flux measurements: the InGOS inter-comparison field experiment
    Peltola, O. ; Hensen, A. ; Helfter, C. ; Belelli Marchesini, L. ; Bosveld, F.C. ; Bulk, W.C.M. van de; Elbers, J.A. ; Haapanala, S. ; Holst, J. ; Laurila, T. ; Lindroth, A. ; Nemitz, E. ; Röckmann, T. ; Vermeulen, A.T. ; Mammarella, I. - \ 2014
    Biogeosciences 11 (2014). - ISSN 1726-4170 - p. 3163 - 3186.
    water-vapor - atmospheric methane - mixing-ratio - wpl terms - path - ch4 - attenuation - accuracy - strategy - quality
    The performance of eight fast-response methane (CH4) gas analysers suitable for eddy covariance flux measurements were tested at a grassland site near the Cabauw tall tower (Netherlands) during June 2012. The instruments were positioned close to each other in order to minimise the effect of varying turbulent conditions. The moderate CH4 fluxes observed at the location, of the order of 25 nmol m-2 s-1, provided a suitable signal for testing the instruments' performance. Generally, all analysers tested were able to quantify the concentration fluctuations at the frequency range relevant for turbulent exchange and were able to deliver high-quality data. The tested cavity ringdown spectrometer (CRDS) instruments from Picarro, models G2311-f and G1301-f, were superior to other CH4 analysers with respect to instrumental noise. As an open-path instrument susceptible to the effects of rain, the LI-COR LI-7700 achieved lower data coverage and also required larger density corrections; however, the system is especially useful for remote sites that are restricted in power availability. In this study the open-path LI-7700 results were compromised due to a data acquisition problem in our data-logging setup. Some of the older closed-path analysers tested do not measure H2O concentrations alongside CH4 (i.e. FMA1 and DLT-100 by Los Gatos Research) and this complicates data processing since the required corrections for dilution and spectroscopic interactions have to be based on external information. To overcome this issue, we used H2O mole fractions measured by other gas analysers, adjusted them with different methods and then applied them to correct the CH4 fluxes. Following this procedure we estimated a bias of the order of 0.1 g (CH4) m-2 (8% of the measured mean flux) in the processed and corrected CH4 fluxes on a monthly scale due to missing H2O concentration measurements. Finally, cumulative CH4 fluxes over 14 days from three closed-path gas analysers, G2311-f (Picarro Inc.), FGGA (Los Gatos Research) and FMA2 (Los Gatos Research), which were measuring H2O concentrations in addition to CH4, agreed within 3% (355–367 mg (CH4) m-2) and were not clearly different from each other, whereas the other instruments derived total fluxes which showed small but distinct differences (±10%, 330–399 mg (CH4) m-2).
    Agricultural peatlands: towards a greenhouse gas sink - a synthesis of a Dutch landscape study
    Schrier-Uijl, A.P. ; Kroon, P.S. ; Hendriks, D.M.D. ; Hensen, A. ; Huissteden, J. van; Leffelaar, P.A. ; Berendse, F. ; Veenendaal, E.M. - \ 2014
    Biogeosciences 11 (2014). - ISSN 1726-4170 - p. 4559 - 4576.
    anemometer (co)sine response - covariance flux measurements - cut-away peatland - eddy covariance - carbon balance - water-vapor - n2o - exchange - meadow - soil
    It is generally known that managed, drained peatlands act as carbon (C) sources. In this study we examined how mitigation through the reduction of the intensity of land management and through rewetting may affect the greenhouse gas (GHG) emission and the C balance of intensively managed, drained, agricultural peatlands. Carbon and GHG balances were determined for three peatlands in the western part of the Netherlands from 2005 to 2008 by considering spatial and temporal variability of emissions (CO2, CH4 and N2O). One area (Oukoop) is an intensively managed grass-on-peatland area, including a dairy farm, with the ground water level at an average annual depth of 0.55 (±0.37) m below the soil surface. The second area (Stein) is an extensively managed grass-on-peatland area, formerly intensively managed, with a dynamic ground water level at an average annual depth of 0.45 (±0.35) m below the soil surface. The third area is a (since 1998) rewetted former agricultural peatland (Horstermeer), close to Oukoop and Stein, with the average annual ground water level at a depth of 0.2 (±0.20) m below the soil surface. During the measurement campaigns we found that both agriculturally managed sites acted as C and GHG sources and the rewetted former agricultural peatland acted as a C and GHG sink. The ecosystem (fields and ditches) total GHG balance, including CO2, CH4 and N2O, amounted to 3.9 (±0.4), 1.3 (±0.5) and -1.7 (±1.8) g CO2-eq m-2 d-1 for Oukoop, Stein and Horstermeer, respectively. Adding the farm-based emissions to Oukoop and Stein resulted in a total GHG emission of 8.3 (±1.0) and 6.6 (±1.3) g CO2-eq m-2 d-1, respectively. For Horstermeer the GHG balance remained the same since no farm-based emissions exist. Considering the C balance (uncertainty range 40–60%), the total C release in Oukoop and Stein is 5270 and 6258 kg C ha-1 yr-1, respectively (including ecosystem and management fluxes), and the total C uptake in Horstermeer is 3538 kg C ha-1 yr-1. Water bodies contributed significantly to the terrestrial GHG balance because of a high release of CH4. Overall, this study suggests that managed peatlands are large sources of GHGs and C, but, if appropriate measures are taken, they can be turned back into GHG and C sinks within 15 years of abandonment and rewetting. The shift from an intensively managed grass-on-peat area (Oukoop) to an extensively managed one (Stein) reduced the GHG emissions mainly because N2O emission and farm-based CH4 emissions decreased.
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