Branched-chain amino acid ratios modulate lipid metabolism in adipose tissues of growing pigs

The effects and roles of branched-chain amino acid (BCAAs) ratios in lipid metabolism in adipose tissues of pigs are still unkown. We used pigs (Large White x Landrace, 35 +/- 2 d) to investigate the effects of varying BCAA ratios (Leu: Ile: Val = 1:1:1, 1:0.75:0.75, 1:0.51:0.63, 1:0.25:0.25) on growth, carcass traits, and fat metabolism in adipose tissues. Results showed that as the ratio declined, the weight of total fat mass reduced while the adiponectin concentrations increased (P < .05), with the lowest/highest values observed in the 1:0.25:0.25 group, respectively. Moreover, varying BCAA ratios modulated the expression of genes related to adipose tissue function (P < .05). Concomitant with these changes, the 1:0.25:0.25 group increased/decreased the phosphorylation of AMPK alpha/mTOR, respectively (P < .05). The mRNA abundance of PGC-1 alpha and IL-15 were also increased in diets with BCAA ratios from 1:0.75:0.75 to 1:0.25:0.25. Our data suggest that dietary BCAA ratios in the adequate range, i.e. 1:0.75:0.75-1:0.25:0.25, modulate adipose tissue function including fatty acid synthesis, transport, and oxidation, lipolysis, and adipokine secretion. These effects are partly mediated by AMPK-mTOR pathway and associated with mitochondrial biogenesis, the AMPK-PGC-1 alpha axis, and IL-15 secreted by muscle tissues.