Effects of Glutamine and Glycyl-glutamine on Growth Performance and Endocrine Function of Weaned Piglets

Forty Landrace and 32 Yorkshire purebred piglets weaned at the age of 21 days were selected and divided into 4 groups based on breed, weight and gender. Pigs in Group A (control) was fed the basal diet and pigs in Group B, C and D as three trial groups were fed the basal diet added 0.5% glutamine, 0.25% glycly-glutamine and 0.5% glycly-glutamine, respectively. The trial lasted 21 days to investigate the effect of glycyl-glutamine and glutamine on the growth performance and endocrine function of the weaned piglets. The results showed that daily gain was increased significantly (P(0.05)), feed conversion ratio was improved and levels of free thiiodothyronine (FT_3), free thyroxine (FT_4) and insulin-like growth factor-Ⅰ (IGF-Ⅰ) in blood tended to be increased in Groups B and C, and level of insulin in blood was increased significantly (P0.05) in Group D at the age of 42 days. Level of cortisol in blood was decreased significantly in Groups C and D. Addition of glutamine or glycyl-glutamine to the basal diet decreased the diarrhea occurrence ratio significantly(P0.05). The results indicated that addition of glycyl-glutamine could regulate endocrine function and improve growth performance in piglets.