Animal performance and gut microbiota of cattle as affected by the unfermented or fermented total mixed ration

Diet regulates the gut microbiota, which in turn affects animal performance, but how diet shapes the animal performance and gut microbiota remains largely unknown. To fill this gap, the author conducted a comprehensive study of the influence of total mixed ration (TMR) or fermented TMR (FTMR) on the animal performance and gut microbiome. Sixteen Simmental male cattle were randomly allocated to two treatments (one cattle per pen). The animals were fed with the TMR and FTMR diets respectively. The results showed that the contents of ADF, NDF, cellulose and total cellulose in the FTMR were significantly decreased (p < 0.05), the average daily weight gain of the Simmental male cattle shows an increasing trend (TMR: 0.31 vs. FTMR: 0.62), while no significant (p = 0.2382) difference was found between the two treatments. The metagenomics analysis showed significant (p < 0.05) difference in the α-diversity and β-diversity, and the dominant bacterial genera were Weissella, Lactiplantibacillus, Levilactobacillus and Companilactobacillus. The 16S rRNA sequencing indicated that a significant (p = 0.018) difference in the bacterial communities between the cattle fed with TMR or FTMR diet, while no significant (p < 0.05) differences were detected on the primary genus. It can be found that the FTMR diet increased the average daily gain of cattle by improving the chemical composition and microbial functional profile of the FTMR diet, and affected the growth performance of cattle.