Ruminant Nutrition: Fats, Fatty Acids, Oils, and Glycerin Supplementation I

Understanding of the bovine fecal microbiome could contribute to solving issues regarding animal production, cattle health and food safety. The objective of this study was to examine the influence of diet on the fecal microbiome in feedlot cattle. The next-generation pyrosequencing technology was used to investigate fecal microbiomes of 426 cattle fed one of 3 diets: finishing diet (83% dry-rolled corn, 13% corn silage, 4% supplement), late growing diet (66% dry-rolled corn, 26% corn silage, 8% supplement), and early growing diet (70% corn silage and 30% alfalfa haylage). A total of 2,149,008 16S rRNA gene sequences were obtained from 333 cattle with at least 2,000 sequence reads and classified into taxa using the RDP classifier. One-way ANOVA followed by Tukey’s test was used to compare the mean abundance of a taxon among the 3 diet groups. Firmicutes was the first predominant phylum and accounted for more than 50% of total sequences in all 3 diet groups. Bacteroidetes was the second predominant phylum in the finishing and the late growing diet groups, while TM7 was the second predominant phylum in the early growing diet group. The genera Fecalibacterium, Anaerovibrio, Prevotella, Parabacteroides and Pantoea were significantly more abundant (P < 0.0001) in the late growing diet group than in other 2 groups, while the genera Oscillibacter, Turicibacter, Coprococcus, Clostridium, Blautia, Lactobacillus and Subdoligranulum were significantly more abundant (P < 0.0001) in the finishing diet group than other 2 groups. The abundance of the genera Sporacetigenium, Anaerovorax, Propionibacterium and Akkermansia was significantly higher (P < 0.0001) in the early growing diet than other 2 diet groups. A principal coordinates analysis of the unweighted UniFrac showed that bovine fecal microbiomes were separated based on diets. The present study indicates that diet has an effect on the fecal microbiome of cattle, particularly between cattle fed forage-rich and grain-rich diets. USDA is an equal opportunity provider and employer.