Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2015
Publication Date: 11/10/2015
Publication URL: http://handle.nal.usda.gov/10113/61652
Citation: Myer, P.R., Wells, J.E., Smith, T.P.L., Kuehn, L.A., Freetly, H.C. 2015. Cecum microbial communities from steers differing in feed efficiency. Journal of Animal Science. 93(11):5327-5340. doi: 10.2527/jas2015-9415
Interpretive Summary: Feed is the primary cost associated with beef production. Cattle’s digestive system contains bacteria that process and ferment the feed which aids in digestion. The nutrient profile that the animal receives is dictated by the fermentation products of the bacteria. The bacterial community will partially aid in determining how feed will be broken down and processed, as well as what fermentation products the animal will be presented. Outside of the rumen, studies that relate gut microbiome to cattle performance are sparse. The relationship between bacterial community and feed efficiency is poorly understood. We found that there are shifts in populations of some bacteria in the cecum of beef cattle associated with feed efficiency.
Technical Abstract: Aims: To characterize the microbial communities of the cecum among steers differing in feed efficiency. Methods and Results: Individual feed intake (FI) and body weight (BW) gain were determined from animals fed the same ration, within two contemporary groups of steers. BW gain was regressed on FI for each contemporary group, and the four most extreme steers within each Cartesian quadrant were sampled (n=16/group). Bacterial 16S rRNA gene amplicons were sequenced from the cecal content using next-generation sequencing technology. No significant changes in diversity or richness were indicated, and UniFrac principal coordinate analysis did not show any separation of cecum microbial communities. However, the relative abundances of microbial populations and operational taxonomic units revealed significant differences between feed efficiency groups. Firmicutes was the dominant phylum in all cecal groups, and accounted for up to 81% of the populations among samples. Populations were also dominated by families Ruminococcaceae, Lachnospiraceae, and Clostridiaceae, with significant population shifts in taxa, including genera Coprobacillus, Parabacteroides, Blautia, Ruminococcus, Oscillospira, and Prevotella. Conclusions: This study suggests the association of the cecum microbial community with bovine feed efficiency at the 16S level. Significance and Impact of the Study: This study aids in the comprehensive evaluation of microbial associations with feed efficiency in the gastrointestinal tract of beef cattle.