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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Systems analysis of Mycoplasma hyopneumoniae to improve vaccine production
Kamminga, Tjerko - \ 2017
University. Promotor(en): Vitor Martins dos Santos, co-promotor(en): Peter Schaap; J.J.E. Bijlsma. - Wageningen : Wageningen University - ISBN 9789463436519 - 152
interdisciplinary research - molecular biology - mycoplasma hyopneumoniae - vaccines - systems biology - systems analysis - pigs - pneumonia - animals - interdisciplinair onderzoek - moleculaire biologie - vaccins - systeembiologie - systeemanalyse - varkens - longontsteking - dieren

Mycoplasma hyopneumoniae (M. hyopneumoniae) is a bacterial pathogen that has evolved from a gram-positive ancestor and specifically colonizes the lower respiratory tract of pigs where it causes enzootic pneumonia and plays a major role in the development of respiratory disease in pigs. Whole-cell inactivated vaccines are available that lower the severity of disease and are widely applied in pig industry to prevent clinical signs and improve pig herd health. However, production of these vaccines is challenging because it is not known which bacterial components are needed for protection and complex cultivation media are needed because growth requirements are not completely understood. The aim of this thesis was to understand growth and survival strategies of M. hyopneumoniae during infection, to integrate this knowledge with metabolic modeling under conditions used for vaccine production and apply this knowledge to improve the current production process for M. hyopneumoniae vaccines.

Chapter 1 provides a general introduction into the disease, treatment and prevention methods with a focus on vaccines. I then introduce the characteristics of the M. hyopneumoniae genome, transcriptome and review the current knowledge on infectious mechanisms and the response of the pig to infection and vaccination. Finally, I discuss the challenges related to vaccine production and introduce systems biology tools that will be applied in the thesis. In chapter 2 we define a strategy for risk-based process development of bacterial vaccines which provided the framework for future studies performed during this thesis. We propose to integrate the academic workflow for rational strain design with the industry standard for process design. Systems biology tools, especially genome-scale metabolic models, play an essential role in this strategy because application of these tools reduces process risks and increases process understanding. Therefore, in line with this strategy, we created a manually curated genome-scale metabolic model of M. hyopneumoniae which we applied to dynamically model the cultivation step in the vaccine production process (chapter 3). We found that only 16% of cellular energy in a standard fermentation was used for growth and 84% was used for non-growth associated maintenance. By model-driven experimentation we were able to increase the fraction of cellular energy used for growth by addition of pyruvate to the production medium, and showed in dedicated fermentor experiments that the improved process reached a 2.3 times higher biomass yield. Although the metabolic model helped to increase process yield, it did not allow prediction of a defined cultivation medium without components from porcine origin. Therefore, to better understand the dependency of M. hyopneumoniae on host derived components, we performed a functional comparison of 80 mycoplasma genomes and used multivariate and machine-learning algorithms to relate functional capability to the specific host and niche of mycoplasma species (chapter 4). This analysis allowed us to identify protein domains possibly needed for growth and survival in the pig lung. In addition, we found that protein domains expected to be essential for bacterial growth were not persistently present in mycoplasma genomes suggesting that alternative domain configurations exist that bypass their essentiality. To better understand whether the proteins we identified as possibly important for survival in pigs actually play a role during M. hyopneumoniae infection, we sequenced the bacterial mRNA during infection in chapter 5 and compared the in vivo transcriptome to that of broth grown mycoplasma. We found 22 up-regulated and 30 down-regulated genes during infection (FDR<0.01 and fold change >2LOG2) and identified differentially expressed ncRNAs. In chapter 6 we build upon our mycoplasma basis to further analyse the role of ncRNAs in bacterial genomes. We identified an exponential relationship between the AT content of genomes and the number of ncRNAs and propose that this relation is the result of spurious transcription, which is more likely to occur in AT rich genomes. This hypothesis is further substantiated by showing that spurious transcription demands minimal cellular energy and that overexpression of cis-binding ncRNAs in M. pneumoniae did not influence the level of proteins translated from their overlapping mRNAs. Finally, in chapter 7 I discuss four system strategies, identified in this thesis and derived from recent literature, and discuss how these strategies could be integrated in the metabolic model of M. hyopneumoniae. Lastly, I provide an outlook on the next steps needed for improvement of the production process for M. hyopneumoniae vaccines.

In conclusion, this work provided novel insight in the metabolic capability of M. hyopneumoniae based on the proteome domain content, captured in a genome-scale metabolic model and studied under in vitro and in vivo conditions. Biomass yield of the cultivation step for vaccine production was increased and the basis was laid to further improve the production process for M. hyopneumoniae vaccines using model-based experimentation.

Stadsvarkens als schakel in de circulaire economie
Vijn, M.P. - \ 2017
Ekoland 37 (2017)10. - ISSN 0926-9142 - p. 24 - 25.
varkens - varkenshouderij - stadslandbouw - cradle to cradle - wetgeving - reststromen - voedselveiligheid - varkensvlees - pigs - pig farming - urban agriculture - legislation - residual streams - food safety - pigmeat
Aan welke regelgeving moet je voldoen om varkens in de stad te houden en te voeden met reststromen? Wageningen University & Research heeft hier onderzoek naar gedaan voor de Stichting Stadsvarkens in Ede. Deze stichting heeft als doelstelling het realiseren van een lokale circulaire economie door de inzet van (stads)varkens en de educatie hierover.
Monitoring verduurzaming veehouderij 1.0 : een eerste proeve van een Monitorings-systematiek voor de 15 ambities van de Uitvoeringsagenda Duurzame Veehouderij, met initiële resultaten voor drie diersectoren en een aantal keteninitiatieven
Bos, A.P. ; Puente-Rodríguez, Daniel ; Reijs, Joan W. ; Peet, G.F.V. van der; Groot Koerkamp, Peter W.G. - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1045) - 113
dierenwelzijn - dierlijke productie - melkvee - varkens - pluimvee - huisvesting, dieren - diergezondheid - diergedrag - animal welfare - animal production - dairy cattle - pigs - poultry - animal housing - animal health - animal behaviour
In 2013, the governance network UDV formulated fifteen ambitions towards a sustainable livestock production. In this way, the UDV’s stakeholders defined the long-term goals of an integrated and sustainable livestock production. To what extent have these 15 ambitions been achieved? And, how substantial is the contribution of supra-legal initiatives to this process? In this report, we present the first elaboration of a monitoring system that enables the visualization of the progress made. Moreover, it also enables comparing the different livestock production systems and creates the basis for a comparison between conventional animal production and supra-legal initiatives. In this concept-report the system is applied initially to the three larger livestock production sectors in the Netherlands (i.e., dairy, pigs, and poultry) and –as far as enough data is available– to four supra-legal initiatives. The system is currently under construction. Particularly because it involves interpretation and a number of value-laden choices that –notwithstanding their current support by arguments and references to the literature– should become shared and supported by (at least) the UDV stakeholders in the near future.
Evaluatie Actieplan Stalbranden 2012-2016
Bokma-Bakker, Martien ; Bokma, Sjoerd ; Ellen, Hilko ; Hagen, René ; Ruijven, Charlotte van - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1035) - 80
dierenwelzijn - dierlijke productie - diergezondheid - pluimvee - varkens - melkvee - schapen - geiten - paarden - stallen - brand - voorkomen van branden - veiligheid - animal welfare - animal production - animal health - poultry - pigs - dairy cattle - sheep - goats - horses - stalls - fire - fire prevention - safety
Elearning Cursus mens-dier interactie in de varkenshouderij
Ruis, M.A.W. - \ 2017
Wageningen : Wageningen Livestock Research - 2 p.
dierenwelzijn - dierlijke productie - varkens - diergedrag - diergezondheid - huisvesting, dieren - varkenshouderij - gedrag - behandeling - animal welfare - animal production - pigs - animal behaviour - animal health - animal housing - pig farming - behaviour - treatment
Hoe ervaart een varken de omgeving? En waarom is het van belang om hierbij stil te staan? Deze cursus richt zich op het belang van een goede mens-dier relatie, waarbij onder andere gekeken wordt naar de manier waarop een varken de wereld ervaart. Dit geeft inzicht in de manier van omgang, met als gevolg minder stress voor dier én mens. Het doel is een win-win situatie; het bevorderen van dierge - zondheid en dierenwelzijn dat onder andere zorgt voor meer werkplezier en meer benutting van het productie potentieel van het varken.
Systeemomschrijving “Plateau 2.0”
Hoofs, Anita - \ 2017
Wageningen : Wageningen Livestock Research - 5
dierenwelzijn - varkens - huisvesting, dieren - diergezondheid - diergedrag - animal welfare - pigs - animal housing - animal health - animal behaviour
En varkenshok met plateau is een hok waarin varkens vrij beschikken over twee verblijfsniveaus, één op de begane grond en één op het plateau. Varkens kunnen gemakkelijk het plateau op - en aflopen via een trap. Bij toepassing van een plateau, dat voldoet aan de systeemomschrijving, mag het beschikbare vloeroppervlak van het plateau als beschikbaar vloeroppervlak meegerekend worden.
Simulating pigs : Understanding their motivations, behaviour, welfare and productivity
Boumans, Iris - \ 2017
University. Promotor(en): Imke de Boer, co-promotor(en): Eddy Bokkers; Gert Jan Hofstede. - Wageningen : Wageningen University - ISBN 9789463432122 - 200
pigs - pig farming - sustainability - motivation - animal behaviour - behaviour disorders - animal welfare - simulation models - animal production - varkens - varkenshouderij - duurzaamheid (sustainability) - motivatie - diergedrag - gedragsstoornissen - dierenwelzijn - simulatiemodellen - dierlijke productie

The transition towards sustainable pig production systems is receiving increasing attention nowadays. Pig behaviour plays a central role in sustainability, as it is an important indicator for pig welfare and can also affect other sustainability issues. Understanding behaviour and related welfare consequences requires to understand motivations underlying behaviour. The two aims of this thesis were: 1) to assess the use of agent-based modelling for understanding pig behaviour and underlying motivation, and 2) to apply agent-based modelling for increasing our understanding of pig behaviour, and related animal welfare and productivity performance.

We first explored the use of agent-based modelling with tail biting behaviour in pigs as a case study. An agent-based model was developed to understand the causation of tail biting behaviour. Subsequently, we developed a mechanistic and dynamic simulation model to gain more understanding of feeding behaviour and internal (physiological) factors. The model integrates knowledge from physiology and ethology, and combines growth with a behavioural decision model based on motivation. This model included motivations underlying feeding behaviour and various feeding patterns of an individually housed growing pig. To deepen our understanding of mechanisms underlying feeding patterns of pigs within 24 hours, hormonal circadian rhythms were included in the model in a follow-up study. The circadian rhythms of cortisol and melatonin explained the alternans pattern, a small peak of feed intake at the beginning of the day and a larger peak at the end of the day, of feeding in pigs. Next, an agent-based model of feeding and social interaction in commercially group-housed pigs was developed to deepen our understanding of the complex interaction between internal physiological factors and external social factors. Social factors (e.g. competition level and social facilitation) and behavioural strategies (e.g. avoidance and approach) affected social interactions among pigs and feeding behaviour. The causation of variation among pigs was further explored in this model. Pig characteristics were important in various feeding, social interaction and growth patterns in pigs.

In general, agent-based modelling proved to be a useful method to understand animal behaviour and underlying motivations. It contributed to further understanding of tail biting, feeding and social behaviour in pigs. Furthermore, agent-based modelling showed to be a novel method to find and assess behaviours as welfare indicators, and to contribute to understanding trade-offs and synergies between sustainability issues, such as animal welfare and productivity.

Stalboekje Varkens 2016: handboek voor natuurlijke diergezondheidzorg met kruiden en andere natuurproducten : Natuurlijk gezond met kruiden en andere natuurproducten
Groot, Maria ; Asseldonk, Tedje van - \ 2017
IJmuiden : RIKILT Wageningen UR (RIKILT-uitgave 2016.701) - 168
varkens - veehouderij - biologische landbouw - geneeskrachtige kruiden - diervoeding - diergezondheid - dierenwelzijn - dierlijke productie - pigs - livestock farming - organic farming - herbal drugs - animal nutrition - animal health - animal welfare - animal production
Signaalindicatoren bij handhaving van "Open Normen" voor dierenwelzijn : pilot klimaat in varkensstallen
Vermeer, Herman ; Hopster, Hans - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1017) - 44
dierenwelzijn - dierlijke productie - varkens - huisvesting, dieren - diergedrag - diergezondheid - wetgeving - toezicht - animal welfare - animal production - pigs - animal housing - animal behaviour - animal health - legislation - surveillance
Nutrition of pigs kept under low and high sanitary conditions : effects on animo acid and energy metabolism and damaging behaviour
Meer, Yvonne van der - \ 2017
University. Promotor(en): Walter Gerrits, co-promotor(en): Alfons Jansman; Aart Lammers. - Wageningen : Wageningen University - ISBN 9789463431972 - 181
pigs - feeds - pig feeding - animal nutrition - amino acid metabolism - animal health - energy metabolism - abnormal behaviour - behaviour disorders - immune system - nutrition physiology - varkens - voer - varkensvoeding - diervoeding - aminozuurmetabolisme - diergezondheid - energiemetabolisme - abnormaal gedrag - gedragsstoornissen - immuunsysteem - voedingsfysiologie

It is economically and environmentally important to match the nutrient supply to the nutrient requirements in pig production. Until now, the effects of different sanitary conditions on energy and nutrient requirements are not implemented in recommendations for nutrient composition of pig diets. The current nutrient requirement data are based on studies with pigs in experimental settings, which can be regarded as rather optimal. Changes in nutrient requirements caused by differences in sanitary conditions are poorly documented. As in the pig production sector farm conditions are variable it is of major importance to determine the effects of low sanitary conditions (LSC) on requirements for amino acids and energy in growing pigs. Pigs under LSC have an increased risk of clinical and subclinical infections, resulting in a chronic stimulation of their immune system. Immune system stimulation is known to influence energy and amino acid metabolism. However, most studies in pigs evaluating the relationship between immune system stimulation and nutrient requirements often use specific experimental challenge models. Whereas such models have the obvious advantage of reproducibility and allow mechanistic insight in the effects of stimulating specific parts of the immune system, these models often induce clinical illness, rather than subclinical infections. Results obtained with such models may therefore be difficult to translate to practical situations. Therefore the objective of the present thesis was to study the effect of low and high sanitary conditions (HSC) on amino acids and energy metabolism in pigs. Also interactions between the immune system, nutrient metabolism and damaging behaviour of pigs were considered in this thesis.

The experiment described in Chapter 2 was designed to study the effect of different dietary crude protein levels and extra amino acid supplementation on the growth performance of pigs kept under different sanitary conditions. In a 2×2×2 factorial arrangement, 68 groups of 9 pigs were allocated to either LSC or HSC, and were offered ad libitum access to two different diets, a normal crude protein concentration diet or a low crude protein concentration diet, each having either a basal dietary amino acid profile or supplemented dietary amino acid profile containing 20% more methionine, threonine, and tryptophan compared with the basal profile. The pigs were followed from 10 weeks of age until slaughter. Haptoglobin concentrations in serum and IgG antibody titers against keyhole limpet heamocyanin, collected in the starter, grower, and finisher phases, and pleuritis scores at slaughter were greater for LSC pigs compared with HSC pigs, illustrating that sanitary conditions affected health conditions. The average daily gain and gain to feed ratio were greater for HSC pigs compared with LSC pigs. A 20% increase in dietary supplementation of methionine, threonine, and tryptophan relative to lysine increased gain to feed ratio more in LSC than in HSC pigs. The results therefore illustrated that dietary requirements for methionine. threonine, and tryptophan were greater for LSC compared with HSC pigs.

In Chapter 3 the damaging behaviour of 576 pigs from the experiment in Chapter 2 was evaluated. At 15, 18, and 24 weeks of age, prevalence of tail and ear damage, and of tail and ear wounds was scored. At 20 and 23 weeks of age, frequencies of biting behaviour and aggression were scored by behaviour sampling. The prevalence of ear damage during the finisher phase and the frequency of ear biting were increased in LSC compared with HSC pigs. The frequency of ear biting was increased in low protein fed pigs compared with normal protein fed pigs. The supplemented AA profile reduced ear biting only in LSC pigs. The prevalence of tail wounds was lower for pigs in LSC than for pigs in HSC in the grower phase. Regardless of dietary amino acid profile or sanitary status, pigs fed low protein diets showed more ear biting, tail biting, belly nosing, other oral manipulation directed at pen mates, and aggression than pigs fed normal protein diets, with no effect on ear or tail damage. In conclusion, both LSC and a reduction of dietary protein increased the occurrence of damaging behaviours in pigs and therefore may negatively impact pig welfare.

The experiment of Chapter 4 was designed to quantify the difference in energy requirements for maintenance, and in incremental efficiencies for deposition of dietary energy and protein in the body of clinically healthy pigs kept under LSC or HSC, fed a basal diet either or not supplemented with additional methionine, threonine and tryptophan.

In a 2 × 2 factorial arrangement, 24 groups of 6 pigs each were allocated to either a LSC or HSC, and were offered two different diets having either a basal or a dietary amino acid profile supplemented with methionine, threonine, and tryptophan. For each group of pigs, complete energy and nitrogen balances were determined during two consecutive weeks, during which feed was available ad libitum or at 70% of ad libitum. Fasting heat production was determined over a 25 h period of fasting after a period of restricted feeding. Low sanitary conditions increased fasting heat production from 696 to 750 kJ/(kg BW0.6 . d), regardless of the dietary amino acid supplementation. The incremental efficiency of ingested nitrogen for retention in the body was reduced in LSC pigs from 73 to 53%, but incremental efficiencies of digestible energy intake for fat deposition in the body were unaffected by the experimental treatments. These findings showed that the effects of continuous immune stimulation by introducing LSC, was affecting energy and nutrient efficiencies of pigs both at maintenance level and at a feeding level close to ad libitum intake.

In Chapter 5 diurnal patterns for heat production, respiratory quotient, and carbohydrate and fat oxidation of the pigs studied in the experiment of Chapter 4 were evaluated to get more insight in the mechanisms behind the effects found in Chapter 4. The LSC pigs had reduced activity compared with HSC and a higher resting metabolic rate during the period of restricted feeding, especially during the light parts of the day. Therefore the diurnal energy expenditure pattern of LSC and HSC pigs can be considered as different. Fat and carbohydrate oxidation patterns were not different for LSC and HSC pigs, indicating that protein and fat deposition during the day was similar for LSC and HSC pigs.

Overall, the results of this thesis indicate that both energy and AA requirements are greater in LSC pigs compared with HSC pigs. It is questionable, however, whether it is nutrient and cost effective and biologically possible to satisfy these increased nutrient requirements in LSC pigs, as the incremental efficiency of N for retained protein is low, and ADFI is reduced for LSC pigs compared with HSC pigs. The present thesis demonstrates that care should be taken in reducing dietary protein concentrations to improve protein efficiency in pigs, as it incurs a risk to increased damaging behaviours, particularly when pigs are kept under LSC.

Interactions and functionalities of the gut revealed by computational approaches
Benis, Nirupama - \ 2017
University. Promotor(en): Mari Smits; Vitor Martins dos Santos, co-promotor(en): Dirkjan Schokker; Maria Suarez Diez. - Wageningen : Wageningen University - ISBN 9789463434546 - 247
pigs - mice - digestive tract - digestive system - intestinal microorganisms - intestinal mucosa - computational science - immune system - feeds - animal nutrition - nutrition physiology - animal health - varkens - muizen - spijsverteringskanaal - spijsverteringsstelsel - darmmicro-organismen - darmslijmvlies - immuunsysteem - voer - diervoeding - voedingsfysiologie - diergezondheid

The gastrointestinal tract is subject of much research for its role in an organism’s health owing to its role as gatekeeper. The tissue acts as a barrier to keep out harmful substances like pathogens and toxins while absorbing nutrients that arise from the digestion of dietary components in in the lumen. There is a large population of microbiota that plays an important role in the functioning of the gut. All these sub-systems of the gastrointestinal tract contribute to the normal functioning of the gut. Due to its various functionalities, the gut is able to respond to different types of stimuli and bring the system back to homeostasis after perturbations.

The work done in this thesis uses several bioinformatic tools to improve our understanding of the functioning of the gut. This was achieved with data from model animals, mice and pigs which were subjected to changing environments before their gastrointestinal response was measured. Different types of stimuli were studied (eg, antibiotic exposure, changing diets and infection with pathogens) in order to understand the response of the gut to varying environments. This data was analysed using different data integration techniques that provide a holistic view of the gut response.

Vertical data integration techniques look for associations between different types of ~omics data to highlight possible interactions between the measured variables. Lateral integration techniques allow the study of one type of ~omics data over several time points or several experimental conditions. Using these techniques, we show proof of interactions between different sub-systems of the gut and the functional plasticity of the gut. Of the several hypotheses generated in this thesis we have validated several using existing literature and one using an in-vitro system. Further validation of these hypotheses will increase understanding of the responses of the gut and the interactions involved.

Stadsvarkens : schakel in een circulaire economie : ruimte in wet- en regelgeving voor stadsvarkens : een advies aan Stichting Stadsvarkens Ede
Vermeij, I. ; Bikker, P. ; Holster, H. ; Raamsdonk, L. van; Vijn, M. - \ 2017
Wageningen : Wageningen University & Research, Wetenschapswinkel (Wageningen University &amp; Research Wetenschapswinkel rapport 336) - ISBN 9789463434577 - 32
varkens - varkenshouderij - stadslandbouw - cradle to cradle - wetgeving - reststromen - voedselveiligheid - varkensvlees - duurzame ontwikkeling - pigs - pig farming - urban agriculture - legislation - residual streams - food safety - pigmeat - sustainable development
De Stichting Stadsvarkens te Ede wil weten aan welke regelgeving moet worden voldaan om vier varkens in een bosperceel te houden en te voeden met reststromen. Het doel is het sluiten van kringlopen binnen een circulaire economie. Dit rapport gaat in op de wet- en regelgeving rond diervoeding en op de afzet van het vlees in de setting van Stadsvarkens. Daarnaast wordt het voeren van reststromen in relatie tot diergezondheid belicht. Door studenten is binnen een ACT-traject gekeken naar relevante wetgeving en is een viertal scenario’s geschetst voor het houden van stadsvarkens die gevoerd worden met lokale reststromen. De scenario’s zijn door de onderzoekers tegen het licht gehouden en van kanttekeningen en een advies voorzien. Dit heeft geresulteerd in een ander advies, omdat verschillende knelpunten de eerdere scenario’s niet mogelijk maken.
Onderzoek Raalte : gezondheid biologische biggen : een beetje verwennen die biggen, want dan doen ze het beter
Vermeer, H.M. - \ 2017
Ekoland (2017)2. - ISSN 0926-9142 - p. 24 - 25.
varkenshouderij - gelten - biggen - biologische landbouw - diergezondheid - dierenwelzijn - proefbedrijven - uitloop - spenen - varkens - pig farming - gilts - piglets - organic farming - animal health - animal welfare - pilot farms - outdoor run - weaning - pigs
Biologisch opgefokte gelten zijn socialer en spenen meer en zwaardere biggen dan gangbaar opgefokte gelten. Biggen die al in de zoogperiode een stukje weide krijgen als uitloop hebben na het spenen sneller diarree, maar doen het tot 25 kg beter dan biggen zonder weidegang. Dit zijn de belangrijkste conclusies uit de allerlaatste proef van 50 jaar onderzoek op het varkensproefbedrijf in Raalte.
Development of pigs raised in a group housing system for lactating sows and their litters
Nieuwamerongen, S.E. van - \ 2017
University. Promotor(en): Bas Kemp, co-promotor(en): Liesbeth Bolhuis; Nicoline Nieuwenhuizen-Soede. - Wageningen : Wageningen University - ISBN 9789463431392 - 270
pigs - piglets - sows - biological development - group housing - lactation - weaning - environmental enrichment - animal behaviour - performance - varkens - biggen - zeugen - biologische ontwikkeling - groepshuisvesting - lactatie - spenen - omgevingsverrijking - diergedrag - prestatieniveau

The aim of this thesis was to investigate the development of pigs that were raised in a newly developed group housing system for lactating sows and their litters, with a focus on the transition around weaning and performance later in life. The starting point of our multi-suckling (MS) system was the natural behaviour of pigs, and the system consisted of 5 farrowing pens connected to a communal area, which included a communal feeding area. Litters were grouped at 1 week of age. Compared with a conventional farrowing system (in which a sow and her piglets are housed in a pen in which the sow is confined individually in a crate), the MS system provided a more spacious and complex environment, with more social and physical enrichment. Before weaning, we found that MS piglets showed more feed-directed behaviour and less damaging behaviours, such as tail biting, than conventionally housed piglets. After weaning at 4 weeks of age, when housed in a more physically and socially enriched pen, MS-raised piglets showed a higher feed intake, a higher weight gain, more play behaviour, and less maladaptive behaviour than the conventionally raised piglets that were housed in a standard nursery pen. In a follow-up study, in which all pigs were housed under equal and enriched conditions after weaning, we found that piglets raised in the MS system had a higher feed utilisation and a lower carbohydrate absorption in an oral sugar absorption test in the early post-weaning phase. In a subsequent study, the same animals were used to investigate their social and cognitive development, using behaviour tests during which pigs competed for access to feed. We found few differences, but there were indications that the pigs raised pre-weaning in the MS system made more use of social information than the conventionally raised pigs. Lastly, we studied effects of different weaning procedures in the MS system (gradual weaning during 9 weeks of lactation vs. abrupt weaning at 4 weeks of age). Weaning seemed to have less impact for the pigs subjected to the gradual weaning treatment (reflected in weight gain and maladaptive behaviour). Also on the long term during the finishing phase (during which both groups were housed equally from 9 weeks of age), the pigs subjected to the gradual weaning treatment showed less maladaptive behaviour and had fewer body lesions than abruptly weaned pigs. To conclude, the multi-suckling system seems promising for improving pig performance, behaviour, and welfare, especially in combination with a more gradual weaning procedure during an extended lactation.

Veerkracht van varkens
Dixhoorn, I.D.E. van - \ 2017
Wageningen University & Research
dierenwelzijn - dierlijke productie - varkens - varkensstallen - diergedrag - animal welfare - animal production - pigs - pig housing - animal behaviour
Video over huisvesting van varkens; de verschillen tussen een gewoon hok en een verrijkt hok. Hoe kun je een hok verrijken? Wat is het effect op de gezondheid en het welzijn van varkens?
Of proteins and processing: mechanisms of protein damage upon rapeseed processing and their effects on nutritional value
Salazar Villanea, Sergio - \ 2017
University. Promotor(en): Wouter Hendriks; Harry Gruppen, co-promotor(en): Thomas van der Poel; E.M.A.M. Bruininx. - Wageningen : Wageningen University - ISBN 9789462579873 - 182
animal nutrition - rapeseed - rapeseed protein - feed processing - proteins - digestion - pigs - diervoeding - raapzaad - raapzaadeiwit - voedermiddelbewerking - eiwitten - spijsvertering - varkens

Hydrothermal processing is a common practice during the manufacture of protein-rich feed ingredients, such as rapeseed meal (RSM), and feeds. This processing step can induce physical and chemical changes to the proteins, thereby reducing the digestibility and utilization of crude protein (CP) and amino acids (AA). Whilst most literature has linked the chemical changes to the proteins with negative effects on protein digestibility, the effects of the physical changes of the protein conformation have not been considered simultaneously. Hence, the aim of this thesis was to provide further insight into the mechanisms of protein damage during ingredient/feed processing and their effects on protein hydrolysis/digestibility. In Chapter 2, the available literature on the physical changes that occur to vegetable proteins used in swine diets after processing was reviewed. Overall, hydrothermal processing increases the contents of intermolecular/intramolecular β-sheets and disulfide bonds, which were negatively correlated to protein digestibility. The correlations, however, were dependent on the type of protein analysed. When the physico-chemical changes in the proteins occur during processing of the ingredients, proteins usually become less responsive to further processing treatments. Rapeseed proteins were used as model, as this oilseed is hydrothermally processed during the oil extraction process and is further processed when incorporated in animal diets.

Protein damage during production of rapeseed meal

There is high variability in the nutritional value of commercial RSM. The variation is mainly due to the conditions used during the desolventization/toasting step. Therefore, the aim of the experiment in Chapter 3 was to characterize the secondary structure and chemical changes that occur during toasting of RSM and their effects on in vitro protein digestibility. A cold defatted RSM was toasted for 120 min with samples obtained every 20 min. Increasing the toasting time from 0 to 120 min increased protein denaturation by 3-fold and decreased protein solubility by 4-fold, lysine content by 23% and the reactive lysine content by 37%. The proportion of intermolecular β-sheets increased after the initial 20 min of toasting, but steadily decreased thereafter. The contrary was observed for the proportion of α-helices. The changes in the secondary structure of proteins were not correlated to the rest of the physical and chemical changes. Therefore, changes in the secondary structure of proteins cannot be considered good indicators of damage to proteins due to hydrothermal processing. The rate of protein hydrolysis decreased by 2-fold when toasting time was increased from 0 min to 120 min. The changes in protein solubility and lysine/reactive lysine contents were positively correlated to the rate of protein hydrolysis. Changes to the physical conformation of rapeseed proteins occur at faster rates during toasting compared to chemical changes.

In Chapter 4, it was hypothesized that the decrease in the rate of protein hydrolysis with increasing toasting time was due to the reduction in protein solubility. In order to test this hypothesis, the soluble and insoluble protein fractions from each of the RSM studied in Chapter 3 were separated and hydrolysed. Hydrolysis kinetics and the molecular size distribution of the peptides resulting after hydrolysis were analysed. The extent of hydrolysis of the insoluble protein fraction was 44% higher than that of the soluble protein fraction. The rate of hydrolysis of the soluble protein fraction separated from the hydrothermally treated RSM was 3-9 fold higher than that of the insoluble protein fraction. In the insoluble fraction, formation of both disulfide bonds and Maillard reaction products (MRP) (fructosyl-lysine [FL], carboxymethyl-lysine [CML] and carboxyethyl-lysine [CEL]) was noticed, which explains the decrease in the rate of protein hydrolysis with longer toasting times. Overall, increasing the toasting time of the whole RSM and the insoluble protein fraction increased the size of the peptides resulting after enzymatic hydrolysis. A shift in the mechanism of protein hydrolysis from a more one-by-one type to a more zipper-type likely explained the correlations between the rate of hydrolysis and the molecular size distribution after hydrolysis. Protein solubility seems to be a key parameter for understanding the decrease in the rate of protein hydrolysis with increasing toasting time.

The correlations between two in vitro protein digestibility methods and the standardised ileal digestibility in growing pigs of severe thermally-treated soybean and rapeseed meals were studied in Chapter 5. Soybean meal and RSM were toasted in the presence of lignosulfonate in order to induce severe thermal damage to the proteins. In vitro protein digestibility was analysed using the two-step enzymatic method (pepsin at pH 2.0 and pancreatin at pH 6.8) and the pH-STAT method. The standardised ileal digestibility values were obtained from a previous experiment, in which ileal-cannulated growing pigs were used. The degree of hydrolysis after 10 min was positively correlated (r = 0.95, P = 0.046) to the standardised ileal CP digestibility. The in vitro rate of protein hydrolysis using the pH-STAT method and CP digestibility using the two-step enzymatic method tended to be positively correlated to the standardised ileal digestibility of CP (r = 0.91, P = 0.09, for both in vitro methods). In conclusion, both in vitro methods might be used for the in vivo digestibility of severe thermally-treated ingredients.

Effects of diet processing on protein digestibility of RSM with different extents of damage

The processed ingredients (e.g. rapeseed meal) are mixed with other ingredients and processed further during the compound feed manufacturing process. The effects of the diet processing methods (e.g. pelleting and extrusion) on protein digestibility could depend on the extent of the damage of the ingredients used. The aim of Chapter 6 was to test the effects of toasting time of rapeseed meal, diet processing method and the interaction between both on protein digestion along the gastrointestinal tract and apparent/standardised ileal digestibility of CP and AA. Mash, pelleted and extruded diets were manufactured using either 0, 60 or 120 min toasted RSM as the only protein source, for a total of 9 different experimental diets. Whilst increasing the toasting time decreased the contents of lysine and reactive lysine in the diets, no effects were noticed after pelleting or extrusion of the diets compared to the mash. The mean particle size of the diets was reduced from 479 μm in the mash diets to 309 and 211 μm after pelleting and extrusion, respectively. A total of 81 growing boars were individually fed with one of the experimental diets. Following euthanasia, the small intestine was divided in 3 sections of equal length and the contents of the final 1.5 m of each small intestine section were sampled. The apparent CP digestibility for each section of the gastrointestinal tract was used to calculate the rate of CP digestion based on a second order equation. The rate of digestion was higher in the diets containing 0 min toasted RSM compared to the diets that contained 60 or 120 min toasted RSM. The diet processing method tended to affect the rate of protein digestion, with higher rates for the extruded > pelleted > mash diets. Significant effects of the interaction between toasting time and diet processing method were found on the apparent ileal CP digestibility. Whilst a lower apparent ileal CP digestibility was found in the 120 min toasted RSM mash diet compared to the 0 and 60 min toasted RSM mash diets, no differences were observed between the different toasting times in the pelleted and extruded diets. Similar significant interactions were noticed for the apparent ileal digestibility of some dispensable and indispensable AA (e.g. arginine, isoleucine, leucine, methionine, threonine, alanine, glycine, proline, serine). Pelleting of the 60 and 120 min toasted RSM diets increased the standardized ileal digestible CP content by 6 and 15%, respectively, compared to the 60 and 120 min toasted mash diets. Extrusion of the 0, 60 and 120 min toasted RSM diets increased the standardized ileal digestible CP content by 5, 9 and 12%, respectively, compared to the 0, 60 and 120 min toasted mash diets. Similar positive effects of pelleting and extrusion were obtained for the apparent ileal digestible contents of lysine and reactive lysine, especially for the diets that contained RSM toasted for longer times. In conclusion, the severe effects of protein damage during the production of RSM on protein digestibility can be (partially) ameliorated by processing of the diets.

Processing of ingredients and diets can lead to the formation of early (e.g. FL) and advanced (e.g. CML and CEL) MRP. These MRP have been associated with common metabolic disorders, for example atherosclerosis. Absorption of dietary MRP has been previously estimated based on indirect measurements, such as concentrations in blood, urine and faeces, which could be biased by endogenous formation of MRP and deposition in tissues. Hence, the aim of Chapter 7 was to measure the apparent ileal digestibility of early (FL, determined as furosine after acid hydrolysis) and advanced (CML and CEL) MRP. The same diets and ileal digesta samples as in Chapter 6 were used in this study. The 0 min toasted RSM diets (mash, pelleted and extruded) were excluded from this study. Sucrose was added to these diets immediately before feeding in order to increase their feed intake, which could confound the determination of the apparent ileal digestibility of the MRP for these treatments. The content of FL was higher in the 120 min compared to the 60 min toasted RSM diets, whereas it was lower in the extruded diets compared to the pelleted and mash diets. The decrease in FL content after extrusion of the diets can probably be related to conversion of the early into advanced MRP, as the content of CML was higher in the extruded diets compared to the pelleted and mash diets. The contents of FL, CML and CEL were positively correlated to the contents of these compounds in the ileal chyme. The apparent ileal digestibility of FL, CML and CEL for the different diets ranged from -8.5 to 19.1%, -0.2 to 18.3% and 3.6 to 30%, respectively. In conclusion, the apparent ileal digestibility of the early and advanced MRP from thermally-treated RSM diets in growing pigs were overall low and did not seem to be related to the contents of these compounds in the diets.

The results of this thesis indicate that the changes to the physical conformation of proteins during toasting of RSM occur at a faster rate than chemical changes. Both types of changes affect protein solubility, which is important in determining the rate of protein hydrolysis. It is suggested in this thesis that the rate of protein hydrolysis of hydrothermally-processed ingredients is probably the main contributing factor for the in vivo protein digestibility. This was demonstrated, as increasing the toasting time of RSM decreased the rate of CP digestion in growing pigs. The negative effects of longer toasting times on CP and AA digestibility, however, could be ameliorated by pelleting and extrusion of the diets. The positive effects of diet processing methods (pelleting and extrusion) on the digestibility of damaged proteins from thermally-treated ingredients should be taken into account in feed evaluation studies and formulation of practical diets.

Effect van voersamenstelling op bijtgedrag bij varkens
Peet-Schwering, Carola van der; Dirx, Nienke ; Kluivers-Poodt, Marion ; Binnendijk, Gisabeth ; Bolhuis, Liesbeth ; Peet, Geert van der - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1008) - 62
dierenwelzijn - dierlijke producten - varkens - diergedrag - diervoeding - staartbijten - animal welfare - animal products - pigs - animal behaviour - animal nutrition - tail biting
Op Varkens Innovatie Centrum Sterksel is onderzocht of bijtgedrag (staart-, oor- en flankbijten) en staart- en oorschade bij dieren met intacte (niet gecoupeerde) staarten verminderd kunnen worden door de dieren vanaf enkele dagen na geboorte tot afleveren naar het slachthuis voer met extra vezels (verzadigend voer) en/of voer met extra aminozuren (tryptofaan, threonine en methionine) te geven. De resultaten van het onderzoek zijn beschreven in dit rapport.
APP Herkomst varkensvlees : Een theoretische verkenning
Bondt, N. ; Hovens, R.J.C. ; Immink, V.M. ; Baltussen, W.H.M. - \ 2016
Den Haag : Wageningen Economic Research (Essay / Wageningen Economic Research 2016-131) - 9 p.
dierenwelzijn - dierlijke productie - varkens - huisvesting, dieren - transparantie - animal welfare - animal production - pigs - animal housing - transparency
Op verzoek van het ministerie van Economische Zaken heeft Wageningen Economic Research een theoretisch kader opgesteld voor identificatie van vers varkensvlees tot op het niveau van het indivi-duele bedrijf waar de vleesvarkens gehouden zijn. Daarnaast is door middel van een literatuuronder-zoek onderzocht of en hoeveel consumenten willen betalen voor deze informatie.
Het voorkomen van staartbijten bij varkens
Kluivers-Poodt, M. - \ 2016
Wageningen UR Livestock Research
dierenwelzijn - dierlijke productie - varkens - diergezondheid - diergedrag - huisvesting, dieren - animal welfare - animal production - pigs - animal health - animal behaviour - animal housing
Bij veel biggen wordt op jonge leeftijd het staartje er afgehaald, zodat ze elkaar er niet in kunnen bijten. Geen leuke ingreep voor de biggen en veel burgers, dierenartsen en varkenshouders zouden dan ook graag zien dat ermee gestopt wordt. Marion Kluivers, onderzoeker van Wageningen Livestock Research onderzoekt het voorkómen van staartbijten.
Een mooie zwijnenstal! : Les over welzijn van varkens
Ruis, M.A.W. - \ 2016
Wageningen : Wageningen Livestock Research - 4 p.
dierenwelzijn - dierlijke productie - varkens - huisvesting, dieren - diergedrag - diergezondheid - diervoeding - lesmaterialen - animal welfare - animal production - pigs - animal housing - animal behaviour - animal health - animal nutrition - teaching materials
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