Lipoic acid promotes SIRT1 and SIRT4 and mitochondrial biogenesis in skeletal and heart muscles of broilers

Alpha-lipoic acid (ALA) improves feed conversion in broilers in a dose-dependent manner, but its key effects on metabolism are not known. In this study, we characterized in broilers the effects of ALA on the expression and activity of Sirtuin 1 (SIRT1) and Sirtuin 4 (SIRT4) and on mitochondrial biogenesis in skeletal and cardiac muscle. ALA increased SIRT4 expression in cardiomyocytes in culture, and SIRT1 activity increased significantly in heart and breast muscle, indicating the activation of mitochondrial biogenesis, particularly in cardiac tissue. ALA also improved myofibril integrity in the breast and heart muscles, increased mitochondrial number, and enhanced mitochondrial integrity in the heart. A positive effect was also observed in the antioxidant capacity in serum. These findings reveal that ALA enhances mitochondrial function and reduces the adverse effects of rapid growth and high-energy diets, thus rendering it a promising supplement for industrial broiler production.