Stress Responses to Changing Environmental Factors in the Domestic Animals: An Epigenetic Perspective

Extreme environmental variations act as stress factors that disturb homeostasis and reduce the fitness of animals. The outcomes of stress responses range from acclimation to adaptation of animals to stressors. Gene expression patterns shape the neuro-endocrine and cellular signalling involved in these stress responses. Epigenetic modifications are one of the major gene regulatory mechanisms that connect environmental factors and animal response. The dynamic as well as stable modes of epigenetic changes carry the memory of gene regulation at cellular and transgenerational levels. In this review, we highlight the involvement of epigenetic mechanisms in the domestication process, an adaptation to the captive environment and summarize recently identified epigenetic modifications that regulate responses to different environmental stress factors. We underline the possible role of developmentally stable epigenetic mechanisms as the basis for fetal programming methods such as thermal conditioning and prenatal nutritional interventions. These examples indicate the potential scope of understanding epigenetic regulations for improving environmental stress adaptation and performance in domestic animals.