Abstract:[Objective] To explore the effects of cell walls of Saccharomyces cerevisiae on the intestinal microbiota in finishing bulls by 16S rDNA and ITS sequencing. [Methods] A total of 40 simmental crossbred finishing bulls weighing about 550 kg were randomized into 4 groups, with 10 bulls in each group. The control group was fed with a basic diet, and 5, 10, and 15 g cell walls of S. cerevisiae were added to the diet of each bull per day in trial 1, 2, and 3 groups, respectively. The preliminary trial and trial lasted for 10 days and 94 days, respectively. Intestinal feces were collected 7 days before the end of the trial. [Results] 16S rDNA: (1) The Chao and ACE indices in the trial 3 group were higher than those in other groups (P<0.05); (2) Firmicutes and Bacteroidota were the dominant phyla, and Prevotella_9, Faecalibacterium, Succinivibrio,Bacteroides, and Bifidobacterium were the dominant genera; (3) The linear discriminant analysis effect size (LEfSe) revealed one differential species (LDA≥4.0, P<0.05) playing an important role in the trial 2 group. ITS: (1) There was no significant difference in the alpha or beta diversity among groups (P>0.05); (2) Ascomycota with the relative abundance above 50.00% was the dominant phylum. Penicillium, unidentified_Ascomycota_sp.,Aspergillus, Orpinomyces, and Eurotium were the dominant genera; (3) LEfSe revealed 8 differential species (LDA≥3.0, P<0.05), which included 3, 3, and 2 differential species playing an important role in the control, trial 2, and trial 3 groups, respectively. [Conclusion] Under conditions of this study, adding 10–15 g/d cell walls of S. cerevisiae in the basic diet increased the richness of intestinal microbiota and the relative abundance of beneficial bacteria Provetella_9, Tolypocladium, andTorulaspora, which were conducive to improve intestinal microecological environment of finishing bulls.
