Effect of long-term heat stress on production, egg quality and physiological traits in four experimental lines of layers differing in heat tolerance and feed efficiency

International audienc

Assessment of surface temperature variation under chronic high temperature in four experimental layer chicken lines differing for heat resistance and feed efficiency traits

Assessment of surface temperature variation under chronic high temperature in four experimental layer chicken lines differing for heat resistance and feed efficiency traits. 10. European Symposium on Poultry Genetics (ESPG

Importance de la première semaine d'élevage en production avicole de chair

International audienc

Effets d’une acclimatation embryonnaire au froid visant à améliorer les capacités d’adaptation du poulet de chair

It is possible to improve poultry adaptability to variations in ambient temperature by changing egg incubationconditions. Our goal is to improve broiler adaptation to cold environment and achieve a multi-level evaluation ofthe cold incubation technique in different subsequent starting conditions. In a first 21-day study in cages, weidentified the experimental conditions favouring robustness and hatchability without reducing performance. Theincubation conditions tested were a control incubation (IT at constant temperature), incubation with two briefexposures to 15°C at the end of incubation (IF1) or incubation with cyclic declines by 1°C from day 10 to 18 ofembryogenesis (IF2). Chickens were then exposed to standard rearing conditions control ET) or to day/nightvariations in room temperature (EFC cyclical cold rearing), or to continuously cooler ambient temperaturesrequiring adaptation (cold rearing EF). A 2nd experiment crossing incubations IT and IF1 and rearing conditionsET and EF was then conducted in floor pens until 40 days. In our conditions, the "cold" incubation techniquesdid not penalize hatchability of eggs. In cages, in females only, the IF2 incubation treatment degraded feedefficiency while IF1 did not alter growth. Our experiments suggest positive effects of cold incubation and coldrearing on performance in males but show negative interactions between both thermal treatments on a parameterof animal welfare and a meat quality defect. Postnatal cooler rearing could be interesting to limit environmentalimpact if litter moisture is well controlled through ventilation. This multicriterion analysis remains to becompleted to evaluate these perinatal techniques according to the three pillars of sustainability, includingeconomic, social and environmental impacts.Il est possible d’améliorer les capacités d’adaptation des volailles aux variations de température ambiante enmodifiant les conditions d’incubation des oeufs. Notre objectif est de rendre les poulets de chair plus adaptables à un environnement froid. Pour cela, nous avons testé les conséquences de différentes conditions d’incubation sur la croissance de poulets élevés au démarrage à différentes températures ambiantes (Exp. 1), puis nous avons sélectionné des conditions discriminantes pour réaliser une évaluation multicritère de la technique d’incubation au froid. Dans l’expérience 1 menée pendant 21 jours en cage, les conditions d’incubation testées sont une incubation témoin (IT, température constante), une incubation avec deux expositions brèves à 15°C en fin d’incubation (IF1) ou une incubation avec des diminutions cycliques de 1°C des jours 10 à 18 d’incubation (IF2). Les poulets sont ensuite exposés à des conditions d’élevage standard (témoin ET), soit à des températures ambiantes continûment plus fraîches nécessitant une adaptation (Elevage froid EF), soit à des variations jour/nuit de température ambiante (Elevage froid cyclique EFC). Les incubations IT et IF1 et les conditions d’élevage ET et EF sont été retenues pour l’exp.2 menée au sol jusqu’à 40 jours, entre autres car chez les femelles, le traitement d’incubation IF2 dégrade l’indice de consommation tandis que le traitement IF1 n’est pas défavorable pour la croissance. Nos expérimentations suggèrent des effets positifs de l’acclimatation embryonnaire au froid et de l’élevage au froid sur le poids à J40 mais elles mettent en évidence des interactions négatives sur l’occurrence des pododermatites et des stries blanches de la viande. Les conditions de froid postnatal pourraient être intéressantes pour limiter l’impact environnemental de l’élevage, mais nécessitent de contrôler l’humidité des litières et de ventilation du bâtiment. Cette étude multicritère doit maintenant être complétée pour réaliser l’évaluation de ces techniques d’élevage périnatales selon les 3 piliers de la durabilité, c’est-à-dire les piliers économique, social et environnemental

Epigenetics for heat tolerance

Epigenetics for heat tolerance. Symposium CERSA Poultry Production under ho and humid climate condition

Short cold exposures during incubation and postnatal cold temperature affect performance, breast meat quality, and welfare parameters in broiler chickens

International audienceCold stimulations during egg incubation were reported to limit the occurrence of ascites in broilers subjected to cold temperature after 14 d of age. However, data are lacking on the impacts of such strategy in case of cold temperature conditions at start. This study aimed to evaluate the effects of incubation and posthatch cold challenge on performance, breast muscle integrity, and meat processing quality in broiler chickens. Ross 308 eggs were incubated under control temperature (I0, 37.6°C) or subjected to 15°C during 30 min on day 18 and 19 of incubation (I1). Chicks from each group were reared in floor pens either at standard rearing temperature (T0), from 32°C at 0 d to 21°C at 21 d of age, or exposed to colder rearing temperature (T1), from 29°C at 0 to 21°C at 21 d of age. All birds were then kept at 21°C until slaughter (day 40), when body weights (BW), feed conversion ratio (FCR), breast muscle yield, meat processing quality, and the occurrences of meat defects, hock burns, and pododermatitis were recorded. No significant impact of incubation conditions on hatchability was observed. At day 40, BW was more under T1 than under T0 conditions, with T0 females (but not males) presenting more BW after I1 than after I0 conditions. In the whole period, T1 chickens presented lower FCR than T0 chickens and higher breast meat yields at day 40. The occurrence of white striping was more in I1T1 males than in all other groups, except for the I0T1 males. Hock burns were more frequent in I1T1 males than in all females and I0T0 males, whereas the occurrence of pododermatitis was lower in T0 males than in other groups. Despite some positive effects of I1 incubation on growth after starting under low ambient temperature, this study reveals the limits of such strategy concerning chicken health and welfare, demonstrating that early thermal environment is a major component of the quality and sustainability of chicken meat production

Evaluation of new incubation strategies to increase the sustainability of broiler production in the context of climate change

In the past decades the genetic selection of fast-growing broilers has resulted in large improvements of grouwth and feed efficiency. However, thsi progress led to an increased sensivity of broilers to their environment. Average global temperature is expected to increase with higher variability and higher environmental impacts. Thus, the challenge is to develop and evaluate new strategies and technologies to improve broiler robustness without reducing flock performances

Sustainability of broiler production in the context of climate change - Evaluation of new incubation strategies

National audienc