Effect of Bacillus subtilis CGMCC 1.1086 on the growth performance and intestinal microbiota of broilers

Aims: Probiotics have been proved to be the most preferred and effective alternative to antibiotics as growth promoter and pathogens inhibitor in poultry industry. In this study Bacillus subtilis CGMCC 1.1086 as a probiotic bacterium was administered in diet and its effects on both the growth performance and the caecal microbiota of broilers were evaluated. Methods and Results: A total of 240 male Arbor Acres (AA) broilers were randomly allocated into two treatment groups of basal diet without any addition of probiotics and basal diet containing B. subtilis CGMCC 1.1086. The body weight of broilers was measured individually at 32, 39 and 46 days of bird age. Furthermore, MiSeq high-throughput sequencing analysis of 16S rRNA was used to investigate the bacterial community structure in the caeca of broilers. The results indicated that broilers receiving diet supplemented with B. subtilis CGMCC 1.1086 showed 27.7% higher daily weight gain than those of control during 2 weeks. The feed conversion ratio (FCR) of B. subtilis CGMCC 1.1086 group was also improved by 10.3%. In the caeca of broilers fed with B. subtilis CGMCC 1.1086, the relative abundance of Alistipes, Odoribacter, Ruminococcus, Blautia and Desulfovibrio were higher, while the potential pathogens such as Staphylococcus and Escherichia-Shigella were lower than those of control. Conclusions: The probiotic B. subtilis CGMCC 1.1086 can effectively improve the growth performance and FCR of broilers via the beneficial modulation of caecal microbiota. Significance and Impact of the Study: The effect of B. subtilis on growth performance of broilers was evaluated and the relationship between growth and caecal microbiota was revealed. The results of this study help to promote application of probiotics in poultry industry.