Prenatal corticosterone exposure programs growth, behavior, reproductive function and genes in the chicken

The aim of this review paper was to understand the role of prenatal corticosterone exposure on growth, aggressive behavior, reproductive performance and gene expression in the chicken. The phenotype, physiology, reproductive function and behavioral characteristics of an organism are not only influenced by genetic factors, but also by environmental factors that play a critical role in shaping offspring morphology. Exposure to excess glucocorticoids during embryonic development influences offspring growth, physiology and behaviors associated with alterations of hypothalamic-pituitary-adrenal axis, hypothalamic-pituitary-gonadal axis and serotonergic system gene expression. Another influential factor for phenotype, physiology and behavioral development is maternal derived steroid hormones that deposit in the egg. In avian species, maternal influences have aroused much attention after the discovery that avian eggs contain a variety of maternal derived steroid hormones. In addition, the environment condition during ontogeny has played a critical role in behavioral development. In avian species, for example laying chicken, high quality mother care produced chicks that were less fearful. Laying hen maternal care is found to reduce cannibalistic pecking phenomenon. Genetic selection and selection experiments will also play a critical role in animals breeding for the housing systems of the future. To optimize animal welfare and to reduce risks factors such as pecking behavior, fundamental approaches are required that merge selection of the optimal genotype with provision of a positive environment for parents and offspring, both throughout ontogeny and later life