Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 389

  • help
  • print

    Print search results

  • export
    A maximum of 250 titles can be exported. Please, refine your queryYou can also select and export up to 30 titles via your marked list.
  • alert
    We will mail you new results for this query: keywords==vleeskuikens
Check title to add to marked list
Losse bijlage bij rapport 'Onderzoek naar kritische succesfactoren voor een laag antibioticumgebruik bij vleeskuikens'
Wiegel, J. ; Holstege, M.M.C. ; Bouwstra, R.J. ; Lauwere, C.C. de; Kluivers-Poodt, M. ; Bokma-Bakker, M.H. - \ 2017
Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 1065B) - 115
dierenwelzijn - dierlijke productie - vleeskuikens - pluimvee - diergezondheid - animal welfare - animal production - broilers - poultry - animal health
Onderzoek naar kritische succesfactoren voor een laag antibioticumgebruik bij vleeskuikens: rapport van het project Kritische Succesfactoren Pluimvee (KSF Pluimvee)
Bokma-Bakker, M.H. ; Wiegel, J. ; Holstege, M.M.C. ; Lauwere, C.C. de; Kluivers-Poodt, M. ; Bouwstra, R.J. - \ 2017
Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 1065A) - 78
dierenwelzijn - dierlijke productie - diergezondheid - pluimvee - vleeskuikens - animal welfare - animal production - animal health - poultry - broilers
Commissioned by AVINED and the Ministry of Agriculture, Nature and Food Quality, research is carried out to identify critical success factors for low antibiotic use in broilers. By analysis of sectoral databases, associations between farm and flock characteristics and antibiotics use are determined. With the results of an additional survey, differences in technical and social factors between structural low and high users of antibiotics are examined.
Stalboekje Pluimvee 2017 : Handboek voor natuurlijke pluimveegezondheidzorg met kruiden en andere natuurproducten
Groot, Maria ; Puls-van der Kamp, Ineke ; Asseldonk, Tedje van - \ 2017
Wageningen : RIKILT Wageningen University & Research (RIKILT uitgave 2017.701) - 107
pluimveehouderij - pluimvee - diergezondheid - dierenwelzijn - medicinale planten - geneeskrachtige kruiden - dierziektepreventie - dierlijke productie - biologische landbouw - handboeken - vleeskuikens - hennen - poultry farming - poultry - animal health - animal welfare - medicinal plants - herbal drugs - animal disease prevention - animal production - organic farming - handbooks - broilers - hens
De stalboekjes zijn oorspronkelijk gemaakt voor de biologische veehouderij (versies 2009 en 2011) in het kader van onderzoek voor Biokennis. Deze uitgave is in 2014 en 2015 aangevuld met nieuwe middelen en inzichten en aangepast voor toepassing in de gangbare pluimveehouderij. Dit betekent o.a. dat een hoofdstuk over vleeskuikens is toegevoegd en het leghennen stuk is uitgebreid. Het streven om het gebruik van antibiotica terug te dringen vraagt om een ander management. Goede voeding, huisvesting en hygiëne zijn hierbij belangrijk. In dit boekje worden aanwijzingen gegeven om met natuurlijke middelen de gezondheid van de dieren te bevorderen en zo ziektes te voorkomen. Tevens kunnen middelen worden ingezet om de ernst van de ziekte te reduceren. Doel is tevens om de dierenartsen te informeren over de mogelijkheden van natuurproducten en de wetenschappelijke onderbouwing hiervan inzichtelijk te maken.
Het effect van een verhoogde rustplaats op het gebruik en het gedrag bij opfok vleeskuikenouderdieren
Emous, R.A. van; Gunnink, H. ; Binnendijk, G.P. - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1047) - 19
dierlijke productie - pluimvee - vleeskuikens - vleeskuikenouderdieren - huisvesting, dieren - diergedrag - animal production - poultry - broilers - broiler breeders - animal housing - animal behaviour
Bringing eggs and bones to light : affecting leg bone development in broiler chickens through perinatal lighting schedules
Pol, Carla W. van der - \ 2017
University. Promotor(en): Bas Kemp, co-promotor(en): Henry van den Brand; Inge Van Roovert-Reijrink. - Wageningen : Wageningen University - ISBN 9789463431422 - 214
broilers - limb bones - biological development - embryonic development - eggs - light regime - incubation - hatching - circadian rhythm - animal pathology - animal health - poultry farming - vleeskuikens - beenderen van ledematen - biologische ontwikkeling - embryonale ontwikkeling - eieren - lichtregiem - broeden - uitbroeden - circadiaan ritme - dierpathologie - diergezondheid - pluimveehouderij

Leg bone pathologies are a common problem in broiler chickens, and they can lead to decreased welfare and poor production performance. It can be speculated that the ae­tiology of some leg bone pathologies lies, to some extent, in suboptimal early life bone development. One factor that can be speculated to affect bone development, and conse­quently leg health, in broiler chickens is application of light. Light has several properties, such as light intensity, color, duration, and schedule. The present thesis focuses on ligh­ting schedules. Aim was to investigate how lighting schedules applied during incubation and in the early post hatch period (the brooding period) affected leg bone development throughout a broiler’s life and leg health at slaughter age.

In 4 studies, effects of eggshell temperature (EST) and lighting schedule during incuba­tion and in the brooding period on leg bone development, leg health, and production parameters were explored. The first study found that an EST of 39.4°C led to lower bone dimensions at hatch than an EST between 37.8 and 38.6°C. It was then decided that incubation experiments on bone development would best be performed at a constant EST of 37.8°C, as this is also an EST that leads to good hatchability and chick quality. In two studies, the effects of circadian lighting schedules during incubation on leg bone development and leg health were investigated. Staining of the embryonic leg bones sho­wed that applying a circadian lighting schedule of 12 hours of light, followed by 12 hours of darkness (12L:12D) resulted in an earlier onset of embryonic ossification of the tibia than continuous light (24L). Compared to 24L, 12L:12D furthermore resulted in higher tibia weight and length, and higher tibial cortical area, cortical thickness, and second moment of area around the minor axis at hatch as revealed by MicroCT scanning. It was furthermore found that 12L:12D resulted in a lower incidence of the leg pathology tibial dyschondroplasia. Continuous darkness (24D) was mostly intermediate. On the other hand, a circadian lighting schedule of 16 hours of light, followed by 8 hours of darkness (16L:8D) did not show the same stimulatory effect on leg bone development, as no dif­ferences in gene expression markers involved in embryonic ossification were found, leg bone dimensions at hatch were not increased, and bone mineral content as determined by DXA scanning was not higher for 16L:8D. It can therefore be speculated that the dark period should exceed 8 hours per day during incubation for increased bone dimensions and ossification. However, incidence and severity of the leg bone pathologies in the form of bacterial chondronecrosis with osteomyelitis and epiphyseal plate abnormalities were lowest for broilers exposed to 16L:8D during incubation, and tibial dyschondroplasia tended to be lower for 16L:8D than for 24D. Interactions between incubation and mat­ching or mismatching post hatch lighting schedules were not found. It was speculated that the endocrine factors (pineal) melatonin, growth hormone, corticosterone, and IGF- 1 were a pathway through which light affected leg bone development, but no evidence was found to support this hypothesis. Production performance was not greatly influen­ced by incubation lighting schedule, but 24L was found to result in higher body weights at slaughter age than 16L:8D and 24D. In the final experiment, lighting schedules were applied during the brooding period from day 0 to 4 after hatching and leg bone develop­ment was measured at day 4 post hatch. 24L led to increased leg bone dimensions, but lower developmental stability of the leg bones than a lighting schedule with 1 or 6 hours of darkness after every 2 hours of light.

The overall findings of this thesis suggest that continuous light during incubation and in the brooding period had a detrimental effect on embryonic and early post hatch leg bone development and health. The involvement of endocrine factors was not clarified from the current results. Applying a light-dark rhythm during incubation may improve embryonic leg bone development and leg health at slaughter age compared to continuous light and continuous darkness, without affecting post hatch production performance, but it appears that the dark period should last longer than 8 hours per day for optimal leg bone development.

First week nutrition for broiler chickens : effects on growth, metabolic status, organ development, and carcass composition
Lamot, David - \ 2017
University. Promotor(en): Bas Kemp, co-promotor(en): Henry van den Brand; Peter Wijtten. - Wageningen : Wageningen University - ISBN 9789463430777 - 187
broilers - animal nutrition - poultry feeding - feeds - growth - metabolism - carcass composition - nutrition physiology - vleeskuikens - diervoeding - pluimveevoeding - voer - groei - metabolisme - karkassamenstelling - voedingsfysiologie

During the first week of life, broiler chickens undergo various developmental changes that are already initiated during incubation. Ongoing development of organs such as the gastro- intestinal tract and the immune system may affect the nutritional requirements during this age period. Despite the residual yolk that is available at hatch and that may provide nutritional support during the first days after hatch, the growth performance may be affected by the time in between hatch and first feed intake. Furthermore, it remains largely unknown to what extend nutritional composition of a pre-starter diet, as well as feed availability directly after hatch have an effect on physiological development directly after hatch, but also at later age. The aim of this thesis was to determine the impact of feed availability and feed composition provided during the first week of life on short-term physiological development, as well as potential long-term effects on growth performance of broiler chickens. Especially early hatched chickens were suggested to benefit more from direct feed access compared to midterm and late hatched chickens, as they tended to have a higher body weight gain during the first week after hatch. A delay in feed access for 48 h resulted in lowered body weight gain and feed intake when compared to direct feed access, but so did a short (13 to 26 h) delay in feed access after hatch. In the latter case, delayed feed access resulted in a lower weight to length ratio of the jejunum and ileum at 4 d of age compared with chickens with direct feed access. Although delayed feed access after hatch resulted in lower body weight gain during the first week after hatch and thereafter, it can be discussed whether this is truly an impairment of long-term growth or just a delayed onset of growth. With respect to feed composition, the inclusion of fish oil and medium chain fatty acids in a pre-starter diet had minor effects on humoral immune function. Inclusion of medium chain fatty acids did result in higher body weight gain and lowered feed efficiency during the first week of life, but only during the period it was provided. Feeding increased diet densities during the first week of life, obtained by formulating diets with different dietary fat levels, resulted in an increased gain to feed ratio, whereas body weight gain and feed intake decreased. Despite the shift in dietary energy supply from carbohydrates to fat and the perceived lower fat digestibility in young broiler chickens, nitrogen metabolizability and fat digestibility were not affected in the current study by feeding increased diet densities. The relative crop, liver and pancreas weights decreased when feeding increased diet densities, whereas the length of the entire intestinal tract increased. This suggests that broiler chickens repartition visceral organ development in response to feeding more concentrated diets during the first week of life. Interestingly, protein and fat accretion were not affected. Continued feeding of increased diet densities after 7 d of age resulted in increased BW gain, G:F ratio and metabolizable energy intake, but mainly during the periods that these diets were provided. In summary, even short durations of delayed feed access already impact intestinal development of young broiler chickens. However, a delayed feed access up to 48 h after hatch does not result in impaired growth, but only a delayed onset of growth. Even though digestibility of fats and oils may be suboptimal in young broiler chickens, feeding of these diets does not have to result in lowered performance per se. Young broiler chickens appear to adapt themselves towards high density diets with high fat inclusion levels in the first week of life, enabling them to digest and metabolize these diet types despite a suboptimal capacity for fat digestion. High density diets result in higher growth performance, but only for the period these diets are provided and thus carry-over effects at later age appear to be limited.

Retrospectieve analyse van standaard vastgelegde data in de vleeskuikenproductieketen
Jong, I.C. de; Riel, J.W. van - \ 2017
Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 1013) - 32
vleeskuikens - vleeskuikenproductie - pluimveehouderij - prestatiekenmerken - gegevens verzamelen - gegevensanalyse - nederland - dierenwelzijn - dierlijke productie - broilers - broiler production - poultry farming - performance traits - data collection - data analysis - netherlands - animal welfare - animal production
Ontwikkeling van een rekentool om de ammoniakemissie uit vleeskuikenstallen te kunnen voorspellen
Aarnink, Andre ; Harn, Jan van; Banken, Klaas ; Ogink, Nico - \ 2016
Wageningen : Wageningen Livestock Research (Livestock Research rapport 990) - 73
vleeskuikens - ammoniakemissie - modellen - pluimveehouderij - broilers - ammonia emission - models - poultry farming
Phytate degradation in broilers
Krimpen, M.M. van; Emous, R.A. van; Spek, J.W. ; Kwakernaak, C. - \ 2016
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research report 978) - 50
broilers - phytic acid - digestibility - poultry feeding - vleeskuikens - fytinezuur - verteerbaarheid - pluimveevoeding
Actualisering geuremissiefactor vleeskuikens
Ogink, N.W.M. ; Ellen, H. ; Mosquera, J. - \ 2016
Wageningen : Wageningen Livestock Research (Livestock Research rapport 960) - 25
vleeskuikens - pluimveehouderij - stankemissie - regelingen - nederland - broilers - poultry farming - odour emission - regulations - netherlands
The aim of this study was to advice on the update of the odour emission factor for broiler houses that is used in the national regulation to control nuisance from odour from livestock (Rgv) in the Netherlands. The update was based a statistical analysis of odour emission data from field studies carried on 28 broiler barns between 1996 en 2014. The main conclusion drawn from this analysis was that the odour emission under current management conditions is higher than the so far used odour emission factor in the Rgv-regulation. The current odour emission factor in the Rgv assigned to broiler houses without additional air cleaning techniques amounts 0.24 OUE/s per placed bird. It is advised to adjust this factor to 0.33 OUE/s per placed bird.
Gezonde vleeskuikens - Een goede start: belang van voer en water : Kennisclip
Ruis, M.A.W. - \ 2016
Dierenwelzijnsweb
dierenwelzijn - dierlijke productie - diergezondheid - antibiotica - pluimvee - vleeskuikens - animal welfare - animal production - animal health - antibiotics - poultry - broilers
Een gezond kuiken kan onder optimale omstandigheden zijn voordeel doen van directe beschikking over voer en water. Het kuiken kan de dooierrest dan beter benutten voor ontwikkeling, immuniteit en groei. De juiste temperatuur van de omgeving is hierbij een zeer belangrijke factor, want als kuikens het koud of te warm hebben eten ze niet en zal van een goede start geen sprake zijn.

In de kuikenbroederij komen kuikens niet allemaal tegelijk uit. De kuikens die het eerst uit komen, moeten wachten totdat alle kuikens uit zijn, en dat kan nog wel een dag duren. Daarna worden de kuikens verwerkt en geteld, en worden ze naar de boerderij gebracht. Zo kan het wel 36 uur duren voordat de eerst uitgekomen kuikens voer en water krijgen.

Innovaties in de pluimveehouderij richten zich op vroege voeding als pluspunt onder optimale omstandigheden: direct verstrekken van water en voer in de uitkomstkast, en het laten uitkomen van broedeieren in de stal.

In opdracht van Wageningen UR Livestock Research en het Ontwikkelcentrum, project 'Naar gezonde kalveren en kippen' (BO-20-011-032). Meer informatie over diergezondheid en dierenwelzijn: www.dierenwelzijnsweb.nl
Gezonde vleeskuikens - hygiëne troef: een beetje preventie is geen preventie : Kennisclip
Ruis, M.A.W. - \ 2016
Dierenwelzijnsweb
dierenwelzijn - dierlijke productie - diergezondheid - antibiotica - pluimvee - vleeskuikens - animal welfare - animal production - animal health - antibiotics - poultry - broilers
Ziekteverwekkers bij vleeskuikens kun je indelen in virussen, bacteriën en parasieten. Antibiotica werken alleen tegen bacteriën. De voornaamste bacteriën bij vleeskuikens zijn E-coli en enterococcen. De meest voorkomende virussen zijn ademhalingsvirussen. Van de parasieten komt de darmparasiet Eimera veelvuldig voor, veroorzaker van coccidiose.

Ziekteverwekkers kunnen op een bedrijf en in de stal worden binnengebracht door personen, voertuigen, het pluimvee zelf, voer, water, ongedierte, materialen en de lucht. Ze kunnen ook al aanwezig zijn in de stal. Er moet dus aandacht besteed worden aan zowel bedrijfshygiëne (externe biosecurity) als stalhygiëne (interne biosecurity).

In opdracht van Wageningen UR Livestock Research en het Ontwikkelcentrum, project 'Naar gezonde kalveren en kippen' (BO-20-011-032). Meer informatie over diergezondheid en dierenwelzijn: www.dierenwelzijnsweb.nl
Gezonde vleeskuikens - Schoon en smakelijk: belang van goede kwaliteit drinkwater : Kennisclip
Ruis, M.A.W. - \ 2016
Dierenwelzijnsweb
dierenwelzijn - dierlijke productie - diergezondheid - antibiotica - pluimvee - vleeskuikens - animal welfare - animal production - animal health - antibiotics - poultry - broilers
Goede kwaliteit drinkwater is essentieel voor een gezond vleeskuiken. Niet alleen aan de bron, maar ook daar waar de dieren het water opnemen: bij de nippel dus. Goed drinkwater is niet alleen belangrijk voor optimale bedrijfsresultaten, maar ook voor voedselveiligheid en diergezondheid.

Van onderzochte watermonsters uit de drinknippel bleek bijna 8 procent ongeschikt en bijna 20 procent minder geschikt als drinkwater voor pluimvee! De kwaliteit van drinkwater wordt vooral beïnvloed door de mogelijke aanwezigheid van biofilm aan de binnenzijde van de drinkleiding. Deze bestaat uit micro-organismen die groeien op afzettingen van vuil en mineralen.

In opdracht van Wageningen UR Livestock Research en het Ontwikkelcentrum, project 'Naar gezonde kalveren en kippen' (BO-20-011-032). Meer informatie over diergezondheid en dierenwelzijn: www.dierenwelzijnsweb.nl
Gezonde vleeskuikens : goed ter been: belang van een goede strooiselkwaliteit : Kennisclip
Ruis, M.A.W. - \ 2016
Dierenwelzijnsweb
dierenwelzijn - dierlijke productie - diergezondheid - antibiotica - pluimvee - vleeskuikens - animal welfare - animal production - animal health - antibiotics - poultry - broilers
Voetzoollaesies zijn aantastingen van de voetzolen van vleeskuikens. Bij een milde laesie is er sprake van een oppervlakkige aantasting (verkleuring, verdikking) van de huid van de voetzool. Bij een ernstige laesie is de opperhuid aangetast tot in de diepere huidlagen en is er sprake van onderhuidse ontstekingen. Deze ernstige voetzoollaesies zijn pijnlijk, en zijn een risico voor diergezondheid.

Voetzoollaesies bij vleeskuikens worden veroorzaakt door een slechte strooiselkwaliteit: nat en plakkerig strooisel. De strooiselkwaliteit wordt door veel factoren beïnvloed, zoals het klimaat, de voersamenstelling en ziekten. De aanpak ervan verschilt van bedrijf tot bedrijf. In de Nederlandse regelgeving is een norm voor voetzoollaesies opgenomen die van toepassing is voor de hoogste bezettingsgraad (39-42 kg/m2).

In opdracht van Wageningen UR Livestock Research en het Ontwikkelcentrum, project 'Naar gezonde kalveren en kippen' (BO-20-011-032). Meer informatie over diergezondheid en dierenwelzijn: www.dierenwelzijnsweb.nl
Gezonde vleeskuikens - Campylobacter de baas – belang van het weren van vliegen : Kennisclip
Ruis, M.A.W. - \ 2016
Dierenwelzijnsweb
dierenwelzijn - dierlijke productie - antibiotica - pluimvee - vleeskuikens - animal welfare - animal production - antibiotics - poultry - broilers
Campylobacter is de meest voorkomende bacteriële veroorzaker van voedselinfecties in Nederland. 20-30% van de Campylobacter-besmettingen van de mens wordt veroorzaakt door consumptie van ongaar of onhygiënisch bereid pluimveevlees. De dieren zelf worden er na besmetting niet ziek van.

Vliegen zijn een belangrijke besmettingsbron op pluimveebedrijven. Het weren van vliegen is daarom een belangrijk aandachtspunt, maar moet gecombineerd worden met een goede biosecurity. Momenteel wordt onderzocht wat het effect is van het plaatsen van vliegennetten, zodat pluimveestallen vliegenvrij zijn.

In opdracht van Wageningen UR Livestock Research en het Ontwikkelcentrum, project 'Naar gezonde kalveren en kippen' (BO-20-011-032). Meer informatie over diergezondheid en dierenwelzijn: www.dierenwelzijnsweb.nl
Disentangling the domestic contract : understanding the everyday-life construction of acceptability -or non-acceptability- of keeping and killing animals for food
Nijland, Hanneke J. - \ 2016
University. Promotor(en): Cees van Woerkum; Noelle Aarts. - Wageningen : Wageningen University - ISBN 9789462578296 - 325
meat - vegetarians - vegetarianism - vegetarian diets - killing of animals - meat animals - meat production - households - environmental impact - sustainability - animal welfare - animal production - animal ethics - food - dairy cattle - beef cattle - pigs - poultry - broilers - hens - vlees - vegetariërs - vegetarisme - vegetarische diëten - doden van dieren - slachtdieren - vleesproductie - huishoudens - milieueffect - duurzaamheid (sustainability) - dierenwelzijn - dierlijke productie - dierethiek - voedsel - melkvee - vleesvee - varkens - pluimvee - vleeskuikens - hennen

When we were children learning the names of animals, farm utensils and food products from picture books, talking about farming animals and related food products appeared simple. However, the intricate realities of modern-day farming practices differ momentously from this primary reference - the picture books. The topic brings about polarized responses, both rationally and emotionally, reflecting very diverse outlooks on the world. This dissertation reports on a research, set in the Netherlands and Turkey, that was designed to improve our understanding of the everyday-life construction of the acceptability -or non-acceptability- ofkeeping and killing animals for food, or in other words: to disentangle the domestic contract.

Effects of temperature and CO2 during late incubation on broiler chicken development
Maatjens, C.M. - \ 2016
University. Promotor(en): Bas Kemp, co-promotor(en): Henry van den Brand; I.A.M. van Roovert-Reijrink. - Wageningen : Wageningen University - ISBN 9789462578258 - 196 p.
broilers - embryonic development - temperature - carbon dioxide - incubation - animal physiology - broiler performance - artificial hatching - hatcheries - poultry farming - vleeskuikens - embryonale ontwikkeling - temperatuur - kooldioxide - broeden - dierfysiologie - vleeskuikenresultaten - kunstmatig bebroeden - broedinstallaties - pluimveehouderij

Incubation conditions need to be adjusted to meet embryonic requirements to obtain optimal chick quality and hatchability. Eggshell temperature (EST) can be used as a non- invasive method to determine embryo temperature. A high EST of 38.9°C during the second or third week of incubation negatively affects chicken embryo development and survival compared to a constant EST of 37.8°C during that period. These negative effects of high EST might be due to a dis-balance between metabolic rate and oxygen (O2) availability. However, effects of lowering EST, which might restore the balance between metabolic rate and O2 availability, are largely unknown. Besides EST, the carbon dioxide (CO2) concentration during late incubation also seems to affect embryo development and might even interact with EST. Based on the potential effects of (lower) EST during the last week of incubation and of CO2 during only the hatching phase, the following three aims are derived: 1, to investigate effects of EST during the last phase of the incubation process, with special attention for EST below the general accepted optimal EST of 37.8°C, 2, to examine from which day of the incubation process onward EST should be changed from 37.8°C, and 3, to investigate whether CO2 concentrations are interacting with EST during the hatcher phase.

Time until hatch was longer when an EST of 35.6°C was applied during the last week of incubation, followed by 36.7, 37.8, and 38.9°C, which is probably caused by the lower metabolic rate at an EST below 37.8°C. Hatchability of fertile eggs was not affected at low EST, and EST did not affect time between internal pipping (IP) and hatch. An EST of 35.6 and 36.7°C, resulted in a higher yolk-free body mass (YFBM) at hatch compared to 37.8 and 38.9°C, and residual yolk weight was higher at hatch at 38.9°C compared to all other EST treatments. An EST of 35.6°C resulted in higher hepatic glycogen concentration and amount at IP and hatch compared to all other EST treatments. The proposed mechanism involved is that at lower EST, metabolic rate is reduced, which prevents the embryo from O2 limitation and ensures that fatty acid oxidation from the yolk can be maintained, resulting in energy production to be invested in growth and development. At an EST of 38.9°C, metabolic rate is high, resulting in a relative O2 shortage for the embryo. Consequently, lipid oxidation is reduced, which forces the embryo to switch to alternative energy sources, such as glycogen. Because glycogen storage is very limited in the egg and embryo, alternative energy sources such as amino acids obtained from muscles might be used. A clear interaction between EST and start day of treatment was found for relative heart weight. Relative heart weight was higher at an EST of 35.6°C and decreased with increase in EST. The differences among EST became larger when the EST treatment started earlier.

Effects of CO2 on embryo physiology, embryonic organ development, and chick quality were marginal. EST interacted with CO2 mainly before IP, but effects were minor at hatch. Interactions between EST and CO2 were found at an EST of 36.7 and 37.8°C, but remained absent at an EST of 38.9°C, which might indicate that physiological systems are already challenged due to the higher metabolic rate, which limits the capacity to cope with high CO2 of the embryo.

No effect of start day of treatment was indicated for embryonic organ development and chick quality found at hatch, which suggests that EST affected these parameters only in the last phase of incubation, e.g. from E19 onward. However, first week post-hatch performance was affected by start day of treatment. The beneficial effects of a lower EST of 35.6 and 36.7°C applied during the last week of incubation found at hatch, might contribute to an enhanced development during the first week post-hatch as body weight, carcass weight, and gain to feed ratio were increased.

In conclusion, results of this thesis show that an EST below 37.8°C during late incubation is beneficial for embryo development, organ growth during incubation, and growth performance during the first week post-hatch. In addition, start day of treatment did not affect chick quality and organ growth, except heart weight, at hatch, which implies that effects of EST occur during the hatching phase, e.g. from E19 onward. Although, an effect of start day of treatment was found on first week post-hatch performance, it remains to be investigated whether an EST below 37.8°C leads to improved later life quality characteristics.

Are all eggs equal? : embryonic development and nutrient metabolism in chicken eggs of different origins
Nangsuay, A. - \ 2016
University. Promotor(en): Bas Kemp, co-promotor(en): Henry van den Brand; R. Meijerhof. - Wageningen : Wageningen University - ISBN 9789462577749 - 213 p.
eggs - hens - broilers - characteristics - strains - embryonic development - nutrients - metabolism - hatcheries - poultry - nutrition physiology - eieren - hennen - vleeskuikens - karakteristieken - stammen (biologisch) - embryonale ontwikkeling - voedingsstoffen - metabolisme - broedinstallaties - pluimvee - voedingsfysiologie

Hatching eggs, supplied to hatcheries are originating from different origins varying in breed, strain, and breeder age. These hatching eggs can be different in size, composition and eggshell properties, which might influence nutrient and O2 availability and consequently could affect embryonic development and nutrient metabolism. The aim of this thesis was therefore 1) to investigate effects of egg origin on nutrient and O2 availability, 2) to investigate effects of egg origins on nutrient metabolism and embryonic development and 3) to investigate consequences of different egg origins on the incubation process and hatching characteristics. In five studies, effects of different egg origins on nutrient and O2 availability, nutrient metabolism, embryo development and hatching characteristics were investigated. The first and second study focused on breeder age and egg size. The third study on breed; broilers and layers. The fourth study on broiler strain and the fifth study on breeder age, strain and eggshell temperature (EST). The overall findings in this thesis suggest that hatching eggs from different origins are not equal in availability of nutrients and O2. Nutrient availability is altered through variation in yolk size, especially by the effects of breeder age and breed. O2 availability is altered by differences in eggshell properties, which is influenced by especially breed and broiler strain. The availability of both nutrients and O2 plays a role on nutrient metabolism measured as embryonic heat production (HP) and consequently on embryonic development. Between incubation day (E) E7 and E14, both nutrient and O2 availability might affect nutrient metabolism as shown in the results of the broiler and layer comparison. Between E14 and hatching, the availability of O2 becomes the most determinant factor for nutrient metabolism and consequently for embryonic development. An increase in EST from 37.8 to 38.9°C from E7 onward resulted in an acceleration of nutrient metabolism and embryonic development until E16, but thereafter a high EST resulted in reduced yolk free body mass development. Embryos with an accelerated metabolic speed at an early stage of incubation, caused by an increased EST, might reach limited O2 availability at a higher magnitude than the embryos at a normal EST. As a result, nutrient metabolism is restricted and embryonic development is depressed. It can be concluded that not only the HP, but also the availability of O2 is crucial to be taken into account for developing incubator temperature. The principle is to obtain an optimal EST, which could maintain the balance between O2 requirement (driven by nutrient metabolism) and O2 availability for a continuing optimal nutrient metabolism to generate sufficient energy for embryonic development throughout incubation.

Effects of early life conditions on immunity in broilers and layers
Simon, K. - \ 2016
University. Promotor(en): Bas Kemp, co-promotor(en): Aart Lammers. - Wageningen : Wageningen University - ISBN 9789462576711 - 188 p.
broilers - hens - ontogeny - poultry feeding - chicken housing - immune response - antibiotics - gastrointestinal microbiota - immunology - immunity - vleeskuikens - hennen - ontogenie - pluimveevoeding - huisvesting van kippen - immuniteitsreactie - antibiotica - microbiota van het spijsverteringskanaal - immunologie - immuniteit

ABSTRACT

The course for later life immune responses is set early in life during the developmental phase of the immune system and accordingly disturbances of immune development may have long-term consequences for host health. In terms of immune activation and immune development the gut microbiota play an important role and consequently disturbances of early life microbial colonization may affect host immunity later in life. In chickens, disturbances of microbial colonization may be caused by various early life conditions which in turn may affect robustness of the chick in the long term. The aim of this thesis was to assess the effects of several early life factors including time of access to feed post hatch (immediately or 72 hours delayed), housing conditions, antibiotic treatment, and intestinal pathology on the intestinal microbiota composition, immune development, and specific antibody response later in life in chickens. Additionally, possible differences between broilers and layers were taken into account as unintentional co-selection of immunological traits may have taken place during the selection process for different production traits. Delayed access to feed and administration of antibiotics early in life led to a shift in early life microbiota composition, which seemed to be restored quite quickly in both cases. Microbiota composition in response to DSS was not investigated, but based on rodent studies was expected to be influenced. Ileal immune development, which was assessed in terms of relative cytokine and immunoglobulin mRNA expression levels was not affected by feeding strategy post hatch (early vs. delayed), but a downregulation of ileal immunoglobulin expression levels could be observed during DSS treatment. All early life factors investigated affected the specific antibody response towards an immunological challenge later in life. Interestingly, there seemed to be an interaction between immediate access to feed post hatch and immune responsiveness towards the environment, thus early feeding may influence the adaptive capacity of chickens in different environments. Regarding the differences between breeds it is interesting to note that broilers seem to have developed a more humoral oriented immune strategy, while layers seem to react in a more pro-inflammatory way. Taken together, results suggested that early life conditions may influence priming of the immune system during its developmental phase, leading to altered antibody responses later in life. Furthermore, broilers and layers seem to have developed different immune strategies. Early life conditions as well as possible differences between breeds should therefore be taken into account in future immunological studies.

Transmission of antibiotic resistance from animals to humans : Broilers as a reservoir of ESBL-producing bacteria
Huijbers, P.M.C. - \ 2016
University. Promotor(en): Mart de Jong; Lisette Graat; E. van Duijkeren. - Wageningen : Wageningen University - ISBN 9789462576216 - 156 p.
broilers - man - disease transmission - antibiotic resistance - bacteria - enterobacteriaceae - poultry farming - epidemiology - vleeskuikens - mens - ziekteoverdracht - antibioticaresistentie - bacteriën - pluimveehouderij - epidemiologie

Huijbers, P.M.C. (2016). Transmission of antibiotic resistance from animals to humans: Broilers as a reservoir of ESBL-producing bacteria. PhD thesis, Wageningen University, Wageningen, the Netherlands.

Antibiotic resistance in animals becomes a public health issue when there is transmission of antibiotic resistant bacteria, or their resistance genes, from animals to humans. β-lactam antibiotics are critically important for the treatment of human bacterial infections. Resistance to this class of antibiotics, mediated by extended-spectrum β-lactamases (ESBL) has emerged. Broilers might contribute to transmission to humans due to the high prevalence of ESBL-producing Enterobacteriaceae among their intestinal biome, compared to other livestock species, companion animals, and wildlife. Transmission to humans might occur via the food chain, by direct contact or via the environment. The aim was to investigate transmission of antibiotic resistant bacteria between animals and humans, and more specifically transmission of ESBL-producing E. coli between broilers, and between broilers and humans in varying degrees of contact with these animals. Systematically collected and categorised evidence from literature showed that clinically relevant antibiotic resistant bacteria were present in the natural environment, that is in soil, water, air and wildlife. It was therefore hypothesised that humans in areas with high broiler densities might have an increased risk for carriage of ESBL-producing Enterobacteriaceae. This hypothesis was rejected, as the observed risk was lower for these individuals. The situation might be different for individuals living on broiler farms as ESBL-producing E. coli were detected on all investigated farms. Among broilers, the within farm prevalence approached 100%, and there was no difference between conventional and organic farms at five weeks, i.e. just before slaughter on conventional farms. On organic farms, the prevalence decreased to 80.0% at 70 days, i.e. slaughter age. Not only transmission to humans via the farm environment, but close physical contact with broilers might, therefore, lead to increased risk for carriage. Prevalence among farmers, their family members and employees on both conventional (19.1%) and organic (18.5%) broiler farms was higher compared to humans in the general population (5.1%). Moreover, people in close contact with live broilers showed the highest risk (27.1 vs. 14.3%). Evidence for clonal transmission of ESBL-producing E. coli between humans and broilers was found on conventional farms, and horizontal gene transfer was suspected on both conventional and organic farms. Even without selection pressure from antibiotics ESBL-producing E. coli were able to transmit and persist in an organic broiler flock, which shows that broilers form a reservoir of antibiotic resistance genes. This leads to an increased risk of carriage of humans on farms through direct contact with broilers and possibly via the direct farm environment. As only a very small percentage of the general population is exposed to live broilers, direct contact with broilers does not appear to be important for carriage in the general human population.

Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.