亚甲基水杨酸杆菌肽对白羽肉鸡生长性能和肠道菌群结构的影响

亚甲基水杨酸杆菌肽（bacitracin methylene disalicylate, BMD）具有良好的抑菌活性与安全性，可作为一种药物添加剂用于预防和治疗动物疾病。然而，目前关于BMD对白羽肉鸡的生长性能和肠道菌群结构的影响尚不明确。作者选用3日龄健康白羽肉鸡作为实验对象，分别在基础饲粮上添加50 mg/kg金霉素制剂与高（60.0 mg/kg）、中（40.0 mg/kg）、低（20.0 mg/kg）剂量的BMD进行比较饲喂管理。记录28 d内白羽肉鸡料重比变化，利用第二代高通量测序技术对28 d的白羽肉鸡肠道微生物菌群和组成变化进行测序分析，比较各组间与组内的肠道微生物多样性及主要优势菌群相对丰度差异。结果发现，饲喂不同剂量的BMD和金霉素制剂对白羽肉鸡的生长性能均有一定影响，饲喂60.0 mg/kg的BMD时，白羽肉鸡料重比最低，效果最佳。同时，饲喂BMD与金霉素制剂对白羽肉鸡的肠道菌群也产生了一定影响，造成了菌群多样性下降、丰度上升。与空白组相比，添加BMD和金霉素后拟杆菌门、软壁菌门的优势菌群显著上升（P<0.05），而厚壁菌门显著下降（P<0.05）。在属水平上，Fournierella的相对丰度显著上升（P<0.05），而粪杆菌属的相对丰度显著下降（P<0.05）。研究结果表明，饲喂BMD对白羽肉鸡的生长性能和肠道菌群结构均有促进作用，能够有效降低白羽肉鸡料重比且能够促进肠道菌群的微生态健康。

Effect of Bacitracin Methylene Disalicylate on Growth Performance and Intestinal Microflora Structure of White-Feathered Broilers

Bacitracin methylene disalicylate (BMD) has good antibacterial activity and safety, which can be used as a pharmaceutical additive to prevent and treat animal diseases. However, the effects of BMD on white-feathered broilers, particularly regarding growth performance and intestinal microflora structure, remains unclear. This study selected three-day-old healthy white-feathered broilers as experimental subjects, and compared the feeding management of high (60.0 mg/kg), medium (40.0 mg/kg), and low (20.0 mg/kg) dosages of BMD added in the basal ration, with the addition of 50 mg/kg of chlortetracycline preparation as the positive control group. The changes in feed-weight-ratio of white-feathered broilers within 28 days were recorded, and the second generation high-throughput sequencing technology was used to sequence and analyze the changes in their intestinal microflora and composition at 28 d. The differences in intestinal microflora diversity and relative abundance of major dominant groups were compared between and within groups. The results showed that feeding different doses of BMD and chlortetracycline preparation had an effect on the growth performance of white-feathered broilers chickens. The feed-to-weight ratio of white-feathered broilers was the lowest when 60.0 mg/kg dose of BMD was fed, and the effect was the optimal. Meanwhile, feeding BMD and chlortetracycline preparations also affected the intestinal microflora of white-feathered broilers, resulting in decreased diversity and increased abundance. In addition, for the dominant microflora, compared with the blank group, the BMD and chlortetracycline groups had a significant increase in Bacteroidetes and Tenericutes(P<0.05), while a significant decrease in Firmicutes(P<0.05). At the generic level, the relative abundance of Fournierella significantly increased(P<0.05), while that of Faebacterium significantly decreased(P<0.05). Overall, the results reveal that feeding BMD can promote the growth performance and intestinal microflora structure of white-feathered broilers, effectively reducing the feed-to-weight ratio of white-feathered broilers and promote the micro-ecological health of the intestinal microflora.