Effects of mulberry branch and leaf powder on rumen microflora of Yunnan Yunling cattle

The rumen microbial community plays a crucial role in the degradation and utilization of dietary nutrients. As a new unconventional feed resource, the effect of mulberry branches and leaves on rumen microflora of ruminants is still unclear. In this experiment, six healthy 30-month-old Yunling cattle with an average weight of (400 ± 20) kg were selected. The control group (Group C) and mulberry branch and leaf powder treatment group (Group V) were separated by the self-control method. Group C was fed a basic diet and Group V, a diet supplemented with 7.31% mulberry branch and leaf powder (MBLP). The experimental period was 30 days, including 10 days of pre-feeding and 20 days of normal feeding. The composition of rumen fluid microbiota was analyzed by 16S rRNA sequencing and the bacterial functions predicted using PICRUSt. The results showed that 1 342 operational taxonomic units were obtained by 16S rRNA gene sequencing, which belonged to 182 genera of 19 phyla. The dominant bacteria at the phylum level in both Groups C and V were Bacteroidetes and Firmicutes, and the dominant bacteria at the genus level were Prevotella, Bacteroides BS11 and Rikenellaceae RC9. At the phylum and genus levels, the number of bacteria related to fiber degradation increased, and the number of Bacteroidetes and Prevotella related to non-fiber polysaccharide degradation decreased. The main functions of the rumen microbial community, as predicted by PICRUSt, were amino acid and carbohydrate metabolism. Therefore, adding mulberry branch and leaf powder to the diet appears to have a positive effect on the rumen microbial community diversity and metabolic function, especially by increasing of the proportion of fiber degradation bacteria, a change conducive to the degradation of plant cellulose.