纳豆芽胞杆菌对AA肉鸡生产性能以及免疫功能的影响

目的 探讨纳豆芽胞杆菌作为饲料添加剂对AA肉鸡生产性能和免疫功能的影响。方法 将300只1日龄的AA健康肉鸡，随机分为5组，对照组饲喂基础日粮，实验组在基础日粮中分别添加50、100、150和200 mg/kg纳豆芽胞杆菌（处理组I~IV），检测其对AA肉鸡增重、饲料转化率、新城疫疫苗免疫后的抗体水平和免疫器官指数的影响。结果 在21 d时，处理4个组肉鸡的体重分别较对照组高0.23%、6.16%、8.29%和7.82%，其中处理组II、III与对照组相比差异有统计学意义（P＜0.05）；处理组I、IV与对照组相比差异无统计学意义（P＞0.05）；在7~28 d时处理4个组肉鸡的饲料转化率均稍高于对照组，但差异无统计学意义（P＞0.05）；当21 d时，处理组II、III的效价水平与对照组、处理组I及IV相比差异有统计学意义（P＜0.05）。处理组I~IV的胸腺、脾脏以及法氏囊三项指数均显著优于对照组，尤其是处理组II和III的免疫器官指数提升最为显著（P＜0.05）。结论 在AA肉鸡基础日粮中添加100、150 mg/kg的纳豆芽胞杆菌对于其生产性能的改善和免疫功能的提高有显著效果。

Effects of Bacillus subtitles natto on the growth and immune function of AA broilers

Objective To study the effects of Bacillus subtitles natto as a feed additive on the growth and immune function of AA broilers. Methods 300 healthy AA broilers at age of 1 day were randomly divided into 5 groups. The control group was fed with basal diet, while the treatment groups I, II, III and IV were fed with the basal diet which added 50, 100, 150 and 200 mg/kg of Bacillus subtitles natto respectively. The weight gain, feed conversion rate, antibody level after immunization with Newcastle disease vaccine and immune organ index were observed. Results At Day 21, the weight of broilers was 0.23% higher in group I, 6.16% higher in group II, 8.29% higher in group III and 7.82% higher in group IV than in the control group, respectively; the differences were significant in groups II and III (P0.05). At Day 21, the titers of treatment group II and III were significantly higher than that of control group, group I or group IV, with significant differences (P<0.05). The indexes of thymus, spleen and bursa of Fabricius in the 4 treatment groups were significantly better than those in control group, especially the immune organ indexes of treatment group II and III (P<0.05). Conclusion The addition of 100 and 150 mg/kg of Bacillus subtitles natto into basal diet can significantly improve the production and immune function of AA broilers.