International Symposium on Ruminant Physiology: Paternal nutrient supply-Impacts on physiological and whole-animal outcomes in offspring.

Recent evidence suggests that environmental factors experienced by sires can be transmitted through the ejaculate (seminal plasma + sperm) into the female reproductive tract, influencing fertilization, embryo development, and postnatal offspring outcomes. This concept is termed paternal programming. In rodents, sire nutrition has been shown to directly alter offspring outcomes through sperm epigenetic signatures, DNA damage and oxidative stress, cytokine profiles, and the seminal microbiome. Response variables altered in rodent models, including adiposity, muscle mass, metabolic responses, and reproductive performance, could have major productivity and financial implications for producers if these paternal programming responses are also present in ruminant species. However, a paucity of data exists regarding paternal programming in ruminants. The limited data in the literature mainly point to alterations in the sperm epigenome as a result of sire diet or environment. Global nutrition has been implicated in ruminant models to alter seminal cytokine profiles, which could subsequently alter the uterine environment and immune response to mating. Several reports indicate that embryo development and epigenetic signatures can be influenced by sire plane of nutrition and inclusion of specific feed ingredients into diets (polyunsaturated fatty acids, folic acid, and rumen-protected methionine). Models of sheep nutrition indicate that addition of rumen-protected methionine can affect DNA methylation and offspring performance characteristics extending to the F generation, and that divergent planes of sire nutrition can cause altered hormone profiles and insulin and glucose metabolism in offspring. Almost unlimited opportunities for discovery in this area exist, but researchers are encouraged to target critical questions such as whether and to what extent paternal programming effects are present in common management scenarios, the mechanisms by which paternal programming is inherited in ruminants, and whether the effects of paternal nutrition interact with those of maternal nutrition to influence offspring physiology, whole-animal outcomes, and herd or flock productivity.