The study was conducted to investigate the effects of α-ketoglutarate (AKG) on concentrations of insulin and amino acids in plasma, expression and phosphorylation levels of mTOR and p70S6K in gastrocnemius of piglets challenged by lipopolysaccharide (LPS). Eighteen healthy weanling piglets aged （24±1） days were randomly assigned into 3 treatments (6 replicates per group): control group, LPS group and AKG-LPS group. Piglets in the control and LPS group were fed basal diet, and those in the AKG-LPS group were fed basal diet＋1% AKG. The experiment lasted for 16 days. On d 10, 12, 14 and 16, piglets in the LPS and AKG-LPS group were injected intraperitoneally with LPS at 80 μg/kg, and those in the control group were injected with the same dose of normal saline. On d 16, blood samples were collected after 3 h of LPS injection. On d 17, gastrocnemius samples of all piglets were collected for analysis after being butchered. LPS challenge increased glutamine concentration (P<0.10) and reduced insulin concentration (P<0.05) in plasma, while reduced P-mTOR/T-mTOR and P-p70S6K/T-p70S6K in gastrocnemius (P<0.05). Dietary supplementation of 1% AKG alleviated the increase of glutamine concentration (P<0.05), the decrease of plasma insulin concentration (P<0.10), and the decrease of P-mTOR/T-mTOR, and P-p70S6K/T-p70S6K in gastrocnemius (P<0.05). In conclusion, dietary supplementation of 1% AKG can alleviate the decrease of insulin concentration and increase of glutamine concentration in plasma, and significantly alleviate the decrease of phosphorylation of mTOR and p70S6K induced by LPS challenge.［Chinese Journal of Animal Nutrition, 2010，22（6）:1724-1729］