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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    Clinical and Pathological Findings in SARS-CoV-2 Disease Outbreaks in Farmed Mink (Neovison vison)
    Molenaar, Robert Jan ; Vreman, Sandra ; Hakze-van der Honing, Renate W. ; Zwart, Rob ; Rond, Jan de; Weesendorp, Eefke ; Smit, Lidwien A.M. ; Koopmans, Marion ; Bouwstra, Ruth ; Stegeman, Arjan ; Poel, Wim H.M. van der - \ 2020
    Veterinary Pathology (2020). - ISSN 0300-9858
    COVID-19 - mink - pneumonia - respiratory disease - severe acute respiratory syndrome coronavirus 2 - zoonoses

    SARS-CoV-2, the causative agent of COVID-19, caused respiratory disease outbreaks with increased mortality in 4 mink farms in the Netherlands. The most striking postmortem finding was an acute interstitial pneumonia, which was found in nearly all examined mink that died at the peak of the outbreaks. Acute alveolar damage was a consistent histopathological finding in mink that died with pneumonia. SARS-CoV-2 infections were confirmed by detection of viral RNA in throat swabs and by immunohistochemical detection of viral antigen in nasal conchae, trachea, and lung. Clinically, the outbreaks lasted for about 4 weeks but some animals were still polymerase chain reaction–positive for SARS-CoV-2 in throat swabs after clinical signs had disappeared. This is the first report of the clinical and pathological characteristics of SARS-CoV-2 outbreaks in mink farms.

    Fundamental factors in feed manufacturing : Towards a unifying conditioning/pelleting framework
    Thomas, M. ; Poel, A.F.B. van der - \ 2020
    Animal Feed Science and Technology 268 (2020). - ISSN 0377-8401
    Agglomerate bonds - Conditioning - Cooling - Pelleting - State phase diagram

    This paper discusses some more fundamental properties associated with the physical quality of pelleted animal feed. The focus is on concepts used in chemistry, physics and soft matter research to discuss the impact of time on heat and water diffusion into particles in the conditioning/pelleting process. It is argued that the extent of transformation of feed components as for instance starch is limited by the availability of water and that the distribution of water in the feed mash particle is governed by particle size, water diffusivity and the time available for hydration in the conditioning process. The role of the glass transition in altering the apparent viscosity of the feed mash resulting in a change of the compaction characteristics of the feed mash is discussed. Bond types in feed agglomerates consist of capillary forces during the compaction phase (pelleting) and transform to solid types of bonds during cooling. Overall, time dependent processes as indicated above give rise to observed differences in the final physical pellet quality and observed systems parameters in feed manufacturing.

    SARS-CoV-2 infection in farmed minks, the Netherlands, April and May 2020
    Oreshkova, Nadia ; Molenaar, Robert Jan ; Vreman, Sandra ; Harders, Frank ; Oude Munnink, Bas B. ; Hakze-van der Honing, Renate W. ; Gerhards, Nora ; Tolsma, Paulien ; Bouwstra, Ruth ; Sikkema, Reina S. ; Tacken, Mirriam G.J. ; Rooij, Myrna M.T. de; Weesendorp, Eefke ; Engelsma, Marc Y. ; Bruschke, Christianne J.M. ; Smit, Lidwien A.M. ; Koopmans, Marion ; Poel, Wim H.M. van der; Stegeman, Arjan - \ 2020
    Eurosurveillance 25 (2020)23. - ISSN 1025-496X
    interstitial pneumonia - mink - SARS-CoV-2 - transmission

    Respiratory disease and increased mortality occurred in minks on two farms in the Netherlands, with interstitial pneumonia and SARS-CoV-2 RNA in organ and swab samples. On both farms, at least one worker had coronavirus disease-associated symptoms before the outbreak. Variations in mink-derived viral genomes showed between-mink transmission and no infection link between the farms. Inhalable dust contained viral RNA, indicating possible exposure of workers. One worker is assumed to have attracted the virus from mink.

    Detection of Low Pathogenic Avian Influenza Virus Subtype H10N7 in Poultry and Environmental Water Samples During a Clinical Outbreak in Commercial Free-Range Layers, Netherlands 2017
    Germeraad, Evelien A. ; Elbers, Armin R.W. ; Bruijn, Naomi D. de; Heutink, Rene ; Voorst, Wendy van; Hakze-van der Honing, Renate ; Bergervoet, Saskia A. ; Engelsma, Marc Y. ; Poel, Wim H.M. van der; Beerens, Nancy - \ 2020
    Frontiers in Veterinary Science 7 (2020). - ISSN 2297-1769
    environmental sampling - LPAIV - outbreak - poultry - water

    Wild birds are the natural reservoir of the avian influenza virus (AIV) and may transmit AIV to poultry via direct contact or indirectly through the environment. In the Netherlands, a clinically suspected free-range layer flock was reported to the veterinary authorities by the farmer. Increased mortality, a decreased feed intake, and a drop in egg production were observed. Subsequently, an infection with low pathogenic avian influenza virus was detected. This study describes the diagnostic procedures used for detection and subtyping of the virus. In addition to routine diagnostics, the potential of two different environmental diagnostic methods was investigated for detecting AIV in surface water. AIV was first detected using rRT-PCR and isolated from tracheal and cloacal swabs collected from the hens. The virus was subtyped as H10N7. Antibodies against the virus were detected in 28 of the 31 sera tested. An intravenous pathogenicity index (IVPI) experiment was performed, but no clinical signs (IVPI = 0) were observed. Post-mortem examination and histology confirmed the AIV infection. Multiple water samples were collected longitudinally from the free-range area and waterway near the farm. Both environmental diagnostic methods allowed the detection of the H10N7 virus, demonstrating the potential of these methods in detection of AIV. The described methods could be a useful additional procedure for AIV surveillance in water-rich areas with large concentrations of wild birds or in areas around poultry farms. In addition, these methods could be used as a tool to test if the environment or free-range area is virus-free again, at the end of an AIV epidemic.

    SCIENCE TALKS CORONA: Developing a vaccine
    Poel, W.H.M. van der - \ 2020
    Wageningen University & Research
    Most likely it will take over a year to develop a vaccine, says virologist Wim van der Poel. In this video, Wim shares his views on the current developments of creating a vaccine.
    Corona nu ook bij nertsen: moeten we ons zorgen maken?
    Poel, Wim van der - \ 2020
    Virussen vóór zijn
    Poel, W.H.M. van der - \ 2020
    Wageningen University & Research
    Door globalisering en verstedelijking kunnen ziekten die van dieren op mensen overgaan, zich sneller verspreiden. Vroege detectie kan levens redden. Daarom sporen Wageningse virologen samen met dierenartsen zo snel mogelijk potentiële ziekteverwekkers op bij wilde dieren en vee. De onderzoekers ontrafelen de genetische opmaak van virussen om de risico’s te bepalen en vaccins te kunnen ontwikkelen. Met vakgenoten wereldwijd wisselen ze expertise uit om nieuwe bedreigingen voor te zijn.
    Do animals get coronavirus
    Poel, Wim van der - \ 2020
    Corona niet overdraagbaar op en door dieren
    Poel, Wim van der - \ 2020
    Effects of particle size heterogeneity in milled maize and soybean meal on nutrient content and in vitro organic matter digestibility
    Lyu, Fang ; Poel, A.F.B. van der; Thomas, Menno - \ 2020
    In: Wias Annual Conference 2020 WIAS - p. 63 - 63.
    The mean particle size of ground grains has effects on pig growth performance and gastrichealth. However the variation heterogeneity in particle size distribution may result in differentpig performances, even though the animal was fed the similar mean particle sizedmeals. The hypothesis about non-homogenous nutrient content distribution along with theparticle size distribution might be one of the key reasons to explain this phenomenon. Theobjective of present study was to identify the nutrient content among individual size fractionsof milled maize and soybean meal (SBM), and to relate it to the pig in vitro digestibilitycoefficients, thus gaining insight on how to improve grinding strategy. Maize and SBM wereground by hammer mill through a 2 and 6 mm screen size respectively, and sieved into 7fractions, from < 0.075 to > 3.36 mm. The nutrient composition including dry matter, ash,crude fibre (CF), crude fat, crude protein (CP), starch and in vitro digestibility of organicmatter (OM), CP (SBM) and starch (maize) were measured. The results show that the nutrientcomposition is significantly different (P< 0.001) among these fractional ground grains. Alarge difference in starch levels (754.2 vs 578.9 g/kg ) in maize was observed; CP contentof SBM increased when the sieve size gets larger. A significant difference (P< 0.001) in the invitro digestibility of OM and CP was also observed among the various particle size fractionsin both ingredients. However, the in vitro digestibility of starch did not differ significantly betweeneach size fractions in maize. The regression models relating the nutrient compositionand in vitro digestibility show that, the digestibility of OM was significantly, positively relatedto the starch level. Ash and starch content are positively related to the in vitro digestibilityof starch in maize. As for the SBM, a significant negative correlation was observed betweenCP and CF, crude fat and OM digestibility; ASH and CF had a negative effect onthe digestibility of CP, though crude fat showed a positive influence on the CP digestion.The relationships between the nutrient composition and pig in vitro digestion suggests thepig growth performance differences in practice may be explained by the nutrient contentamong different fractions. This indicates that the grinding strategies should also be consideredwhen designing the feeding formula / manufacturing the feed.
    Comparison of hepatitis E virus sequences from humans and swine, the Netherlands, 2008-2015.
    Hogema, Boris ; Honing-Hakze, R.W. van der; Molier, M. ; Zaaijer, Hans L. ; Poel, W.H.M. van der - \ 2020
    In: WIAS Annual Conference 2020. - WIAS - p. 27 - 27.
    Until the beginning of this century, in the developed world, hepatitis E virus (HEV) was seen as a travellers disease and autochthonous HEV infection was rarely observed. Now a days HEV infections become common and recent studies showed that zoonotic hepatitis E virus genotype 3 infections occur frequently in industrialized countries. Pigs have been shown to be a major reservoir of hepatitis E genotype 3 virus, only the transmission route(s) from pigs to humans are ill-defined. Consumption of undercooked meat products is the likely transmission route however the virus could also spread via surface water or crops. Partly orf 1 and orf 2 sequences of HEV isolates were obtained from individual pigs and from blood donors and hepatitis patients. 372 human samples and at least 10 HEV positive caecum swine samples per year were collected in the Netherlands in 2000 and between 2008 and 2015 and sequenced. All generated HEV sequences from human and pig samples were aligned with a proposed reference set from the literature. In to-tal, 91 HEV ORF1 sequences and 300 HEV ORF2 sequences from pigs, patients and blood donors were included in the analysis. Sequence comparison showed that all sequences were genotype 3 except for six patients (with travel history). HEV gt3c was the most common subgenotype. Whereas the proportion of gt3c significantly increased between 2000 and 2008 it remained constant between 2008 and 2015. Of the circulating HEV subgenotypes, there was no difference observed between the human and the pig isolates. This is compatible with the assumption that HEVs from swine are the major source of HEV infections in humans. Hepatitis E viruses in humans are very likely to originate from pigs, but it is unclear why HEV gt3c has become the predominant subtype in the Netherlands
    'Rapid spread of corona virus is worrying'
    Poel, Wim van der - \ 2020
    Size reduction in feed technology and methods for determining, expressing and predicting particle size: A review
    Lyu, F. ; Thomas, M. ; Hendriks, W.H. ; Poel, A.F.B. van der - \ 2020
    Animal Feed Science and Technology 261 (2020). - ISSN 0377-8401
    Breakage function - Particle size - Pelleting - Pig feed - Size reduction

    Particle size of diets or ingredients plays an important role in pig growth and gut health. The way the size of particles is measured and expressed, however, is limited in explaining pig growth performance differences. This review explores new possibilities to determine, express and predict particle size. Different grinding methods, including the use of roller mills, hammer mills, multicracker and multi-stage grinding were reviewed. Roller milling tends to produce a more uniform particle size distribution (PSD) and consumes less energy, whilst hammer mills have a greater grinding capacity and a higher reduction ratio compared to roller mill. The multicracker system, a more recently developed technology, can be considered cost-effective and ensures grinding capacity. Since the effects of different grinding methods vary, multi-stage grinding, combining different grinding methods, might be a solution to obtain a defined PSD. Particle size determination techniques, including dry/wet sieving, laser diffraction, microscopy, and static/dynamic image analysis are described and compared. It is concluded that more characteristics of particles (e.g. shape, volume or surface area) should be investigated. Besides geometric mean diameter (GMD), particle size can also be expressed with parameters such as D50, D4,3 and span of PSD. Equivalent particle size (EPS) is introduced as a mean of describing the size of particles related to a functional trait of the particles. A meta-analysis was performed by collecting particle size and pig performance data from scientific studies examining the effect of recalculated EPS on pig performance (feed conversion ratio, FCR). Regression/linear modelling shows that recalculated EPS was not better than GMD in explaining pig performance differences due to the high variation among studies. Different expressions of PSD may result in different conclusions. An introduction of describing the breaking behavior of diet ingredients via mathematical models is provided. The development in breakage functions of wheat in roller milling in food preparations indicates that breakage functions are applicable in predicting the output PSD. Functions may also be extended to diet ingredients to be ground in animal feed manufacture. In feed manufacturing diagrams, particle size reduction for downstream processes (e.g. pelleting, extruding, expander processing) should be taken into account when the relationship between pig performance and particle size of diets is investigated. In conclusion, the determination, expression and prediction of particle size can be a new direction for controlling the grinding process in the feed mill to better explain its relationship with pig performance.

    Warmtebehandeling raapzaad onderzoek: promotie onderzoek Sergio Salazar Villanea
    Salazar Villanea, Sergio - \ 2020

    Promotieonderzoek Sergio Salazar Villanea

    Rem op Q-koorts en Lyme
    Poel, Wim van der - \ 2019
    Strijd tegen zoönosen
    Poel, Wim van der - \ 2019
    Les défis de la technologie de l’aliment en nutrition volaille: pertinence et enjeux pour répondre aux attentes industrielles et sociétales
    Poel, A.F.B. van der; Condy, T. ; Moquet, P.C.A. ; Kwakkel, R.P. - \ 2019
    In: Procedure de depot Treizièmes Journées de la Recherche Avicole et Palmipèdes à Foie Gras. - Tours : l'Institut Technique de l'Aviculture (ITAVI) - 8 p.
    Numerous feed technology innovations have been communicated over the last years in poultry nutrition: wet feeding, coarse grinding, use of novel criteria describing the physical properties of the feed and on-line near infrared reflectance spectroscopy. Such innovations influence both the feeding behavior and the digestive physiology of poultry. Hence, they may help egg and poultry meat producers to improve zootechnical performance while reducing environmental impact and antibiotics use, thereby addressing both industrial and societal concerns. Nowadays, the use of such innovations remains, however, experimental. Industrial upscaling of such innovations requires a better understanding of the feeding behavior of poultry: feed technology should be fully committed to support the gut development of birds.
    Future technologies in pigs & poultry nutrition
    Poel, A.F.B. van der; Marchal, J.L.M. - \ 2019
    In: Poultry and pig nutrition / Hendriks, W.H., Verstegen, M.W.A., Babinszky, L., Wageningen Academic Publishers - ISBN 9789086863334 - p. 369 - 396.
    The economic room for technologically and nutritionally more advanced diets will increase in the future. The processing of animal feed currently has a number of beneficial effects including the improvements in feed efficiency and to find the right balance between animal health and efficiency. In the feed mill diagrams, a large diversity of equipment and systems can be found. This diversity is already present for each different unit operations: in the case of particle size reduction, there is a large choice in special equipment and the way the different steps are set up into a grinding system. For agglomeration e.g. these may vary from having large flexibility in more basic production of different feed forms, up to applying sophisticated equipment (expanders, compactors) to improve nutrient digestibility and pellet quality to strive towards high quality feeds. Farms are becoming larger and in certain countries farmer are using on-farm processing of feed ingredients in addition to purchased concentrates. There is a small but growing trend in organic farming to include the use of other ingredients for animal diets such as grass for sows, fermented ingredients, etc. and some are of the opinion that a new business model will emerge in agriculture where the objective has to be a balance between economy, ecology and society, called 'sustainable precision husbandry'.
    Les défis de la technologie de l’aliment en nutrition volaille: pertinence et enjeux pour répondre aux attentes industrielles et sociétales
    Poel, Thomas van der - \ 2019
    Importance of measuring equivalent particle size analysing pig performance data
    Lyu, Fang ; Poel, A.F.B. van der; Thomas, Menno - \ 2019
    In: Proceedings of the 44th Animal Nutrition Research Forum. - - p. 6 - 7.
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