Abstract: 【Objective】 The experiment was aimed to investigate the effects of compound bacteria culture on growth performance,immune function and vaccine antibody titer of Mongolian-Han crossbred mutton sheep. 【Method】 Forty 1.5-month-old Mongolian-Han crossbred male lambs with good health and similar body weight were randomly divided into 2 groups,control group and experimental group,with 4 replicates in each group and 5 lambs in each replicate.The lambs in control group was fed with basal diet,and the lambs in experimental group was fed with additional 30 g/d of compound bacterial culture per sheep on the basis of the basal diet.On the 16th day of the experiment,each lamb was injected with type A foot-and-mouth disease and sheeppox vaccines.The pre-trial period was 7 days and the formal period was 90 days.On the 0th,30th,60th and 90th day of the experiment,the lambs were weighed,blood was collected and serum was separated before morning feeding,and the growth performance,immune and antioxidant indexes were measured.On the 15th,30th and 45th day of the experiment,blood was collected and serum was separated to determine the antibody titers of type A foot-and-mouth disease and sheep pox vaccine. 【Result】 On the 90th day of the experiment,compared with control group,the average body weight of mutton sheep in experimental group were significantly increased (P＜0.05).From 0 to 90 days of the experiment,there was no significant difference in the average daily feed intake (ADFI) and feed to gain ratio (F/G) of mutton sheep between experimental group and control group (P＞0.05),but the average daily gain (ADG) of mutton sheep in experimental group was significantly increased compared to control group (P＜0.05).On the 90th day of the experiment,compared with the control group,the activity of lysozyme (LZM),contents of interleukin-1β (IL-1β),transforming growth factor-β (TGF-β),tumor necrosis factor-α (TNF-α),activities of catalase (CAT) and glutathione peroxidase (GSH-Px),and total antioxidant capacity (T-AOC) in serum of mutton sheep in experimental group were significantly increased (P＜0.05),while the content of malondialdehyde (MDA) was significantly decreased (P＜0.05).On the 45th day of the experiment,compared with control group,the antibody titer of the sheeppox vaccine of mutton sheep in experimental group was significantly increased (P<0.05),while the antibody titer of the foot-and-mouth disease type A vaccine was not significantly different (P＞0.05). 【Conclusion】 The addition of compound bacteria culture could significantly improve the growth performance,immune function and antioxidant function of Mongolian-Han crossbred mutton sheep,and increase the titer of vaccine antibody.

Key words: compound bacteria culture (CBC); Mongolian-Han crossbred mutton sheep; growth performance; immune function; antioxidant function; vaccine antibody titer