本试验旨在探讨L-茶氨酸对黄羽肉鸡生产性能和免疫功能的影响.选用1日龄黄羽肉鸡690只,随机分为6个处理,每个处理5个重复,每个重复23只.6个处理分别为对照组(饲喂无抗生素基础饲粮)、抗生素组[饲喂在基础饲粮中添加10％硫酸黏杆菌素的饲粮,前期(1～3周)添加200 mg/kg,后期(4～7周)添加150 mg/kg]、4个不同梯度(100、200、400和800 mg/kg)L-茶氨酸试验组,试验期为49 d.试验检测了黄羽肉鸡的生产性能、免疫器官指数、肠道分泌性免疫球蛋白A(sIgA)含量及血清溶菌酶活性、抗体水平和免疫细胞因子含量等指标.结果表明:在试验前期,100 mg/kg L-茶氨酸组黄羽肉鸡的体增重显著低于其他各组(P＜0.05),100、200和800 mg/kg L-茶氨酸组黄羽肉鸡的法氏囊指数显著低于对照组(P＜0.05),各L-茶氨酸组黄羽肉鸡的肠道sIgA含量和血清干扰素-γ(IFN-γ)含量显著高于对照组(P＜0.05).在试验后期,与对照组及抗生素组比较,L-茶氨酸对黄羽肉鸡生产性能、免疫器官指数、肠道sIgA的含量影响不显著(P ＞0.05)；100、200和400 mg/kg L-茶氨酸组黄羽肉鸡血清白细胞介素-2(IL-2)的含量显著高于对照组(P＜0.05),200和400 mg/kg L-荼氨酸组黄羽肉鸡血清IFN-γ的含量显著高于对照组(P＜0.05).在整个试验期,各组黄羽肉鸡血清溶菌酶的活性和白细胞介素-4的含量差异不显著(P＞0.05)；一免后第6天,100和200 mg/kg L-茶氨酸组黄羽肉鸡血清新城疫抗体滴度显著低于对照组和抗生素组(P＜0.05),一免后第14天,100、200和400 mg/kgL-茶氨酸组黄羽肉鸡抗牛血清白蛋白(BSA)抗体水平显著高于对照组(P＜0.05),其他各阶段各组间的抗BSA抗体水平和新城疫抗体滴度均差异不显著(P＞0.05).由此可知,饲粮添加L-茶氨酸对黄羽肉鸡生长后期生产性能、免疫器官指数均无显著影响,说明其对黄羽肉鸡后期生长是安全的；同时L-茶氨酸可提高黄羽肉鸡生长前期肠道sIgA的含量、后期血清IL-2的含量及全期血清IFN-γ的含量,从而增强其机体免疫功能.%The purpose of this study was to investigate the effects of L-theanine on the performance and immune function of yellow-feathered broilers. A total of 690 one-day-old yellow-feathered broilers were randomly divided into 6 groups with 5 replicates per group and 23 birds per replicate. The groups were divided into a control group (non-antibiotic group) , an antibiotic group (added 10% of colistin sulphate, 200 mg/kg during 1 to 3 weeks, 150 mg/kg during 4 to 7 weeks) , 4 different levels of L-theanine ( 100, 200, 400 and 800 mg/kg) groups. The trial lasted for 49 days. Performance, immune organ indices, intestinal secretory immunoglobulin A (slgA) , serum lysozyme activity, antibody level and immunocytokine contents were investigated. The results showed as follows-. 1) during the period of 1 to 3 weeks, the body weight gain of 100 mg/kg L-theanine group was significantly lower than that of the other groups (P <0. 05) , the bursa of fabricius index of 100, 200 and 800 mg/kg L-theanine groups was significantly lower than that of the control group (P <0.05). The contents of intestinal slgA and serum interferon-r (IFN-7) in L-theanine groups were significantly higher than those of the control group (P<0.05). 2) During the period of 4 to 7 weeks, there were no significant differences in the performance, immune organ indices and intestinal slgA content among L-theanine groups, control group and antibiotic group. Serum interleukin-2 (IL-2) content of 100, 200 and 400 mg/kg L-theanine groups was significantly higher than that of the control group (P<0.05) , and serum IFN-7 content of 200 and 400 mg/kg L-theanine groups was significantly higher than that of the control group (P<0.05). 3) During the entire experimental period, there were no significant differences in serum lysozyme activity and interleukin-4 (IL-4) content among all groups (P>0. 05). Lower anti-Newcastle disease virus (NDV) titers of 100 and 200 mg/kg L-theanine groups were found on day 6 post primary immunization compared with the control group and antibiotic group (P< 0.05), but higher anti-bovine serum albumin (BSA) antibody levels of 100, 200 and 800 mg/kg L-theanine groups were found on day 14 post primary immunization compared with the control group (P < 0. 05) , and there were no differences in anti-NDV titers and anti-BSA antibody level among all groups during the other periods (P >0. 05). In conclusion, there were no significant differences in performance and immune organs indices during the later trial period of broilers supplemented L-theanine, which indicate that L-theanine is safe for broilers. And the L-theanine supplementation can bring about higher intestinal slgA content of early experimental period, serum IL-2 content of later experimental period and serum IFN-7 content of entire experimental period, so the immune function of broilers are enhanced by the diets supplemented L-theanine. [Chinese Journal of Animal Nutrition, 2012, 24(10) : 1946-1954]
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