Date of this Version
The U. S. meat industry faces a dual challenge: it must reduce the fat content of meat carcasses in order to provide a nutritious product with a minimum of waste, while not affecting meat palatability. The positive effects of marbling (fat deposited within muscle) on tenderness and palatability, as well as a meat grading system that penalizes carcasses with little marbling, make it desirable that animals be produced with minimal amounts of fat stored in depots, such as the subcutaneous and perirenal depots, without markedly decreasing intramuscular adipose tissue. This can be accomplished only if the factors regulating lipid deposition in intramuscular adipose tissue and other fat depots differ substantially.
Previous studies have indicated that marbling scores are not affected by differences in diet to the extent observed for backfat thickness or total carcass fat. Therefore, the primary purpose of this study was to determine the relative contributions of acetate, lactate, and glucose as carbon precursors for fatty acid synthesis in intramuscular and subcutaneous adipose tissue. Additionally, the effects of age and diet on lipogenic activities in both depots were investigated because earlier studies have not demonstrated the interaction between age and diet on lipogenesis in either intramuscular or subcutaneous adipose tissue.