Effects of dietary butyrate supplementation on intestinal integrity of heat-stressed cockerels.

Butyrate modulates intestinal epithelial cell structure and function. Three hundred and sixty Lohmann LSL-Classic layer cockerels were used to investigate the effect of butyrate on heat stress-induced intestinal injury and intestinal integrity. The experiment was conducted from day 85 to 105 of age. The birds were divided randomly into three treatments: control, heat stress (HS), and heat stress provided with butyrate (HSB) at a level of 0.35 g/kg of diet. The control was reared at 21 ± 1 °C throughout the experiment. The HS and HSB treatments were exposed to a cyclic HS (35 ± 1 °C from 09:00 to 13:00 and 21 ± 1 °C from 13:00 to 09:00). Intestinal and mucosal weights, villus height, villus surface area (VSA), absorptive epithelial cell area and intestinal beneficial bacteria were lower in the HS treatment than in the other two treatments (p < 0.05). Heat-stressed cockerels exhibited the highest (p < 0.05) villi injury scores and serum endotoxin levels compared with the other treatments. Dietary inclusion of butyrate increased (p < 0.05) intestinal and mucosal weights, villus height, VSA, absorptive epithelial cell area and intestinal beneficial bacteria counts and reduced (p < 0.05) HS-induced injury in intestinal epithelia as well as intestinal permeability to endotoxin. In conclusion, dietary butyrate exerted protective effects against intestinal damage induced by HS and improved intestinal health and integrity.