Effects of glycyl-glutamine on the growth performance and lipid deposition in Yue-Huang broilers

To investigate the effects of glycyl-glutamine (Gly-Gln) on the growth performance and body composition in Yue-Huang broilers, two hundreds and seventy 9-d-old birds were randomly allocated to 3 groups of 90 birds each, incorporating 3 cages per group. All the birds were offered a commercial starter feed supplemented with 0, 0.01 or 0.05 mg Gly-Gln per kg for next 5 weeks, then given a commercial grower feed for another 5 weeks. The results showed that Gly-Gln could not only significantly increase the body weight of Yue-Huang broilers but also enhanced breast muscle and leg muscle yields, while it declined abdominal fat percentage in a dose-dependent manner. The concentration of triglyceride and total cholesterol (T-CHO) in serum and that of T-CHO in pectoralis major muscle were reduced with the up-regulated mRNA expression of peroxisome proliferatoractivated receptors α (PPAR-α) and down-regulated transcript levels of acetyl-CoA carboxylase (ACC) and sterol regulatory element binding protein-2 (SREBP-2).