Abstract: This study was conducted to investigate the effects of αketoglutarate (AKG) on small intestinal morphology, plasma Dxylose concentration, activities of diamine oxidase (DAO) in plasma and intestinal mucosa, and expression of mammalian target of rapamycin (mTOR) with phosphorylation (PmTOR/mTOR) in the piglets under lipopolysaccharide (LPS) challenge. Eighteen healthy crossbred (Duroc×Landrace×Yorkshire) piglets were randomly assigned into 3 treatment groups (6 replicates per group): control group, LPS group and AKG group. The control and LPS groups were fed the basal diet＋1% starch, and the AKG group was fed the basal diet＋1% AKG. On d 10, 12, 14 and 16, the piglets in the LPS and AKG groups were injected intraperitoneally with LPS at 80 μg·kg1BW, whereas piglets in the control group were injected intraperitoneally with the same dose of physiological saline. On d 16, Dxylose was orally administrated to all pigs at the dose of 0.1g·kg1BW 2 h after LPS challenge, and blood samples were collected 3 h after LPS challenge. All the piglets were sacrificed on d 17 to examine small intestinal morphology and collect intestinal mucosa for analysis. The results showed that: (1) Compared to the control group, the ratio of villus height to crypt depth in duodenum, jejunum and ileum, PmTOR/mTOR in jejunal and ileal mucosa of LPS group significantly decreased (P<0.05), while the activities of DAO in plasma significantly increased (P<0.05). (2) Compared to the LPS group, the ratio of villus height to crypt depth in the duodenum and jejunum ileum, activities of DAO in the jejunal mucosa, Dxylose content in plasma and PmTOR/mTOR in duodenal, jejunal and ileal mucosa of AKG group significantly increased (P<0.05). In conclusion, dietary supplementation with 1% AKG could improve small intestinal morphology and absorption function to some extent and alleviate the intestinal mucosal damage caused by LPS challenge in piglets, which were associated with mTOR signaling pathway.