Rearing hens and increasing their capacity to combat infections
Are early-life conditions important?
Production systems for laying-hens are continuously exposed to infectious pathogens. To prevent infections from spreading through the flock, various control methods are used nowadays. However, these methods not only increase production costs, but also prevent laying-hens from building up their own reserves to combat these threats.
The capacity to adapt in order to withstand threats is considered to be well-developed, if the individual is resilient to periods of stress. This capacity could also be beneficial during challenges posed by infectious pathogens. Not only the genetic background, but also early life – pre- and postnatal – experiences are thought to influence the propensity and capacity to survive threats in later life. The results of the first experiment indicate that early-life conditions do play an important part in developing the capacity to adapt in later life. Future experiments will explore this indication further.
The first experiment in this Ph.D. project was designed to investigate whether, in rearing hens, early-life conditions could indeed influence their resilience against infection in later life. Two contrasted groups were created during incubation and rearing by using normal practice for one group and what are considered to be optimal conditions for the other group (in a 2×2 design) for the first seven weeks after hatching. In later life, these hens were exposed to various pathogens found in poultry production systems.
The results of this study confirmed that early-life conditions did appear to affect responses to infection in later life. The rearing environment seemed to be the most important factor. The early rearing environment not only affected the immune responsiveness to infection, but also influenced the ability to recover from the clinical symptoms caused by the pathogen. The incubation conditions, on the other hand, appeared to have more influence on stress-related parameters. This may explain the occurrence of problem behaviours such as feather pecking in later life.
Animal Breeding & Genomics (nr. 10 Dec. 2008) newsletter published by the Animal Sciences Group
Animal Breeding and Genomics Centre – Wageningen University