Abstract: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.
