Age Related Changes in Bovine Subcutaneous Fat Proteome

Fat is one of the critical aspects for meat quality and animal productivity. However, it is not clear how fat development is regulated in beef cattle during growing and fattening period. This study characterized the proteomic changes in subcutaneous fat from eight steers at 12 and 15 months of age using label free quantification LC-MS/MS. During this period, steers displayed expansion of subcutaneous fat and concomitant changes in the proteomic profiles. The expression of 123 out of 627 identified proteins differed between fat samples taken at two different ages. Functional analyses on differentially expressed (DE) proteins revealed that 20.2% of them were associated with cellular growth and proliferation of adipose tissue. There were 17 DE proteins out of 108 proteins associated with lipid metabolism, which were ACSM1, ANXA1, APOC3, APOH, EHD1, F2, GSN, LMNA, MAP2K1, MYH9, ORM1, PDIA3, RBP4, RENBP, SDHA, SERPINC1, and SERPING1. Expression levels of proteins involved in lipid metabolism indicated a down-regulation in fatty acids synthesis at cellular level at 15 month compared to 12 month old. These results suggest that fatty acid synthesis in adipocytes was adjusted during growth, revealing a coordinated balance between subcutaneous fat mass and the cellular abundance of lipogenic proteins to control the rate of fat deposition in finishing steers. These findings expand our understanding on how proteome of bovine adipose tissue is regulated during growth which might help the development in the future of new strategies to manipulate adiposity improving meat quality and animal productivity.