Role of the early environment in phenotypic variability and adaptation of animals to their environment

Abstract

Farm animals face multiple environmental constraints to which they must adapt. More and more studies are investigating the impact of the early environment on animal phenotypes and their ability to adapt to the various challenges encountered later. Here we review current knowledge on the influence of the early environment on the construction and variability of phenotypes and adaptation of farm animals to their environment, taking examples from different species. We will focus on the roles of three major contributors to the construction of phenotypes: epigenetic mechanisms, microbiota, and behavioural processes. Epigenetic mechanisms, which modulate genome expression under the influence of environmental disturbances during development, can induce a variety of phenotypes whose characteristics can persist into adulthood, or even be transmitted to the next generation. The constitution of the digestive microbiota is also highly dependent on the early environment, and plays an important role in the expression of phenotypes, especially in the field of animal health. Finally, early experiences greatly influence animal's behaviour, especially its learning abilities, which can give it a better chance of adapting to new situations later on. The studies carried out in these fields make it possible to define new levers for action to try to optimise the adaptability of our animals, in particular through the feeding of young animals or their parents or even grandparents, acclimatisation during development, or more generally through changes in the environment, in particular the social environment.