[Objective] This study aimed to investigate the effects of traditional Chinese herbal medicine on the structure of duodenal mucosa of chickens under heat stress. [Method] One hundred and twenty 88-day-old Isa Brown chickens were randomly divided into six groups, including three control groups （normal temperature control group, high temperature control group, high temperature Vc control group） and three high-temperature administration groups （high-dose administration group, moderate-dose administration group, low-dose administration group）. Chickens in normal temperature control group were reared at 14-25 ℃, and those in other five groups were reared at 28-39 ℃. The experiment lasted 10 d. Five chickens in each group were euthanized at 1, 4, 8 and 10 d post-treatment, respectively. The duodenal mucosa was collected and prepared into tissue slices with the conventional method for hematoxylin-eosin （HE） staining. Mucosal thickness, villus length and crypt depth of duodenal mucosa were measured. [Result] Under heat stress, duodenal mucosal thickness and villus length were both significantly lower than those in normal temperature control group, and the duodenal villi were scarce and thin. However, under high temperature conditions, various indicators in high-dose and moderate-dose administration groups were higher than those in high temperature control group and high temperature Vc control group, which exhibited extremely significant differences at 8 and 10 d post-treatment, especially. Moreover, various indicators in high-dose administration group were significantly higher than those in moderate-dose and low-dose administration groups. The traditional Chinese herbal medicine prescription exhibited higher protective effects on duodenal mucosa of chickens under heat stress compared with high temperature Vc control group. [Conclusion] Under heat stress, traditional Chinese herbal medicine reduced effectively the duodenal mucosa damage in chickens.
