To evaluate the renal toxicity of dietary aflatoxin B1(AFB1)and ameliorating effects of added dietary sodium selenite in broiler,renal histopathological changes,ultrastructural changes and renal function parameters were monitored at 7,14,and 21 days of age.Two hundred one-day-old healthy male Avian broilers were divided into four groups,namely control group,AFB1 group(0.3 mg/kg AFB1),+Se group(0.4 mg/kg Se)and AFB1+Se group(0.3 mg/kg AFB1+0.4 mg/kg Se).Compared with that of the control group,the relative weight of kidney was increased in the AFB1 group.There were no significant differences between the AFB1+Se group and the control group.By histopathological observation,the renal epithelia were swelling and necrosis at 7 and 21 days of age.Ultrastructurally,the lipid droplets and expanded endoplasmic reticulum appeared in the plasma of epithelia cells in the AFB1 group.Enlarged mitochondria with degenerated cristae were observed in the+Se group.Compared with the control group,the contents of serum creatinine and serum uric acid in the AFB1 group were increased,while the activity of renal Na+-K+ATPase was decreased.When 0.4 mg/kg selenium was added into the diet containing 0.3 mg/kg AFB1,there were no obvious histological changes in the AFB1+Se group,and the contents of the serum creatinine and serum uric acid contents and the activity of renal Na+-K+ATPase were close to those in the control group.In conclusion,sodium selenite exhibited protective effects on AFB1-induced kidney toxicity in broilers.