How Epigenetics Can Enhance Pig Welfare?

SIMPLE SUMMARY: In the pig industry, new market trends and consumer demands have emerged over the past decades, which includes increased concerns about how animals are raised on farms. As a consequence of consumers’ concerns, technologies capable of predicting animal welfare on farms have been explored. One of the technologies that are permeating the frontier of knowledge in this area are epigenetic biomarkers. Epigenetic biomarkers are biochemical markers surrounding the genome, which may be able to predict the exposures that individuals had during their lifetime. These markers represent an advance in the molecular level accuracy to support the current welfare indicators. In this literature review focused on pigs, we show some studies already carried out, we performed an integrative analysis of the already reported genes surrounding epi-biomarkers, and we highlight the benefits of investing efforts in this research field to enhance animal welfare and consumers’ trust. ABSTRACT: Epigenetics works as an interface between the individual and its environment to provide phenotypic plasticity to increase individual adaptation capabilities. Recently, a wide variety of epi-genetic findings have indicated evidence for its application in the development of putative epi-biomarkers of stress in farm animals. The purpose of this study was to evaluate previously reported stress epi-biomarkers in swine and encourage researchers to investigate potential paths for the development of a robust molecular tool for animal welfare certification. In this literature review, we report on the scientific concerns in the swine production chain, the management carried out on the farms, and the potential implications of these practices for the animals’ welfare and their epigenome. To assess reported epi-biomarkers, we identified, from previous studies, potentially stress-related genes surrounding epi-biomarkers. With those genes, we carried out a functional enrichment analysis of differentially methylated regions (DMRs) of the DNA of swine subjected to different stress-related conditions (e.g., heat stress, intrauterine insult, and sanitary challenges). We identified potential epi-biomarkers for target analysis, which could be added to the current guidelines and certification schemes to guarantee and certify animal welfare on farms. We believe that this technology may have the power to increase consumers’ trust in animal welfare.