摘要Pogostemon cablin essential oil(PEO),extracted from P.cablin,has anti-oxidant,anti-inflammatory,and anti-stress properties,as well as the ability to improve gastrointestinal digestion.This study aims to evaluate the effects of PEO on the performance,rumen epithelial morphology,and barrier function in heat-stressed beef cattle.Thirty-six male Jingjiang cattle at 18 months old were randomly assigned into four groups and fed a diet containing PEO at 0(control),50,100,or 150 mg/kg in the feed concentrate(n=9).All experimental cattle were fed under high temperature and humidity in summer for 60 days.The results indicated that 50 mg/kg of PEO treatment enhanced the average daily gain of beef cattle compared with the control group(P=0.032).All PEO treatments reduced the diamine oxidase activity(P=0.004)and malondialdehyde content(P=0.008)in serum.In addition,the content of 70 kDa heat shock protein in the 100 mg/kg group was increased,and the activity of glutathione peroxidase and total antioxidant capacity in both 100 mg/kg and 150 mg/kg groups were enhanced compared to the control group(P＜0.05).More importantly,PEO treatment with 50 mg/kg enhanced the mRNA relative ex-pressions of occludin in ruminal epithelia but decreased the mRNA relative expressions of c-Jun N-ter-minal kinase,P38 mitogen-activated protein kinases,caspase-3,Beclin1(P＜0.05),and extremely significant declined the mRNA relative expressions of extracellular regulated protein kinases and ubiquitin-binding protein in contrast to the control group(P＜0.01).These findings indicated that dietary PEO supplementation might be favorable to improve growth performance and repairing damaged rumen epithelium of heat-stressed cattle by down-regulating the mitogen-activated protein kinase signaling pathway.