Abstract: 【Objective】 The purpose of the experiment was to explore the effects of different levels of ellagic acid on growth performance,blood biochemical indexes and antioxidant capacity of Kazakh sheep,and to provide reference basis for the application of ellagic acid in ruminants.【Method】 Twenty 3-month-old Kazakh rams with a body weight of (25.58±2.85) kg were randomly divided into 4 groups with 5 sheep in each group.The ellagic acid supplementation levels in control,15 EA,30 EA and 45 EA groups were 0,15,30 and 45 mg/kg BW, respectively.The 60-day feeding experiment was carried out after 5 days of pre-feeding.The fasting weight was weighed every 30 days.Blood samples were collected before feeding on the morning of the 60th days.Growth hormone,insulin-like growth factor-Ⅰ,triiodothyronine,thyroid hormone,glucose,total protein,albumin,globulin,urea nitrogen,triglyceride,total cholesterol,total antioxidant capacity,superoxide dismutase,catalase,glutathione peroxidase and malondialdehyde were measured.【Result】 ① There was no significant difference in initial body weight,final body weight,feed intake,daily gain and F/G of experimental sheep among four groups during the whole trial period (P＞0.05).② There was no significant difference in plasma growth hormone,insulin-like growth factor-Ⅰ,triiodothyronine and thyroid hormone levels of experimental sheep among four groups (P＞0.05).③ Plasma TP contents of experimental sheep in 30 EA and 45 EA groups were increased significantly by 11.28% and 10.46% compared to control group (P＜0.05),and it was increased linearly with the increase of ellagic acid supplementation (P＜0.05).Compared with control group,the plasma ALB content of experimental sheep in three test groups were increased significantly by 17.47%,25.38% and 24.85%,respectively (P＜0.05),and it was increased linearly with the increase of ellagic acid supplementation (P＜0.05).There were no significant differences in the levels of glucose,globulin,urea nitrogen,and total cholesterol in the plasma of experimental sheep among four groups (P＞0.05).The plasma triglyceride content of experimental sheep in 30 EA group was significantly higher than that in control group (P＜0.05).④Compared with control group,plasma total antioxidant capacity and glutathione peroxidase activities of experimental sheep in three test groups were increased linearly with the increase of ellagic acid supplementation (P＜0.05),and plasma total antioxidant capacity in 30 EA and 45 EA groups increased significantly by 10.24% and 11.02% (P＜0.05).Plasma glutathione peroxidase activities in three test groups increased significantly by 29.49%,55.78% and 52.36%,respectively (P＜0.05).【Conclusion】 Adding different levels of ellagic acid to the diet did not have a significant effect on the feed intake,daily weight gain,and plasma levels of growth hormone and insulin-like growth factor in Kazakh sheep.However,it could affect fat and protein metabolism to a certain extent and significantly enhance the body’s antioxidant capacity.The appropriate addition level of ellagic acid was 30 mg/kg BW.

Key words: ellagic acid; Kazakh sheep; growth performance; blood biochemical index; antioxidant capacity