LAUSR

Abstract The current study aimed to determine how Clostridium butyricum (C. butyricum) relieved diarrhea by evaluating its effects on intestinal digestive enzyme activity, barrier integrity, inflammatory responses, and oxidative stress in weaned piglets. A total of 360 weaned piglets that were 25 days old (180 males and 180 females) were randomly assigned to 5 groups in 6 pens, with 12 pigs per pen, and offered the same antibiotic-free corn-soybean-type basal diet for 30 d. The groups were as follows: no additives (control), basal diet + 250 mg/kg C. butyricum (CB1), basal diet + 500 mg/kg C. butyricum (CB2), basal diet + 1,000 mg/kg C. butyricum (CB3), and basal diet + 2,000 mg/kg C. butyricum (CB4). The incidence of diarrhea decreased quadratically as the amount of C. butyricum supplementation was increased, and this decrease was minimized in the CB2 group. Compared with those in the control group, the duodenal amylase and lipase activities were increased quadratically and maximized in the CB2 group, and the jejunal lipase activity was increased cubically in the CB1 group, while the pancreatic trypsin activity was increased linearly and maximized in the CB4 group. The serum concentration of D-lactic acid responded to the increases in the levels of C. butyricum in a quadratic manner; the minimum level was observed in the CB2 group. Jejunal zonula occludens-1 expression displayed linear and quadratic trends following C. butyricum supplementation, with the maximum response observed in the CB3 group. Quadratic and cubic increases were observed in jejunal alkaline phosphatase activity in the CB3 group. The jejunal IL-10 concentration increased, while the jejunal vascular endothelial growth factor concentration decreased quadratically in response to dietary C. butyricum supplementation in the CB2 group. No significant differences among the groups were observed in terms of the jejunal mucosal concentrations of oxidation-associated enzymes and products. In conclusion, dietary supplementation with appropriate doses of C. butyricum could relieve diarrhea in weaned piglets by enhancing digestive enzyme activity, maintaining intestinal barrier integrity, and relieving intestinal inflammation.