The modern version of epigenetics includes the molecular mechanisms that influence the phenotypic outcome of a gene or genome, in absence of changes to the underlying DNA sequence. A host of genomic interrelationships with the diet evidently exist. The broad topic of nutrigenomics is defined as the interaction between nutrition and an individual's genome. Ruminant species have evolved to metabolize the short-chain volatile fatty acids (VFAs, acetate, propionate, and butyrate) to fulfill up to 70% of their nutrient energy requirements. The potential biological roles of VFAs were investigated using the established Madin-Darby bovine kidney epithelial cell line. Butyrate induces cell cycle arrest and apoptosis in bovine cells. Gene expression profiling indicated that butyrate induces many significant changes in the expression of genes associated with regulatory pathways that are critical to cell growth, immune response and signal transduction. Functional category and pathway analyses of the microarray data revealed that several canonical pathways (the cell cycle G2/M DNA damage checkpoint and G1/S checkpoint regulation; pyrimidine metabolism; and purine metabolism insulin-like growth factor axis components) were significantly affected.
