Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2015
Publication Date: 6/1/2015
Publication URL: http://handle.nal.usda.gov/10113/60941
Citation: Myer, P.R., Smith, T.P., Wells, J., Kuehn, L.A., Freetly, H.C. 2015. Rumen microbiome from steers differing in feed efficiency. PLoS One. 10(6):e0129174.
Interpretive Summary: Feed is the primary cost associated with beef production. Cattle’s digestive system contains bacteria that 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 determine what fermentation products the animal will be presented. The relationship between bacterial community and feed efficiency is poorly understood. We found that there are shifts in populations of some bacteria associated with feed efficiency.
Technical Abstract: The cattle rumen has a diverse microbial ecosystem that is essential for the host to digest plant material. Extremes in body weight (BW) gain in mice and humans have been associated with different intestinal microbial populations. The objective of this study was to characterize the microbiome of the cattle rumen among steers differing in feed efficiency. Two contemporary groups of steers (n=148 and n=197) were fed a ration of 57.35% dry-rolled corn, 30% wet distillers grain with solubles, 8% alfalfa hay, 4.25% supplement, and 0.4% urea for 63 days. Individual feed intake (FI) and BW gain were determined. Within contemporary group, total BW gain was regressed on total FI, and the four most extreme steers within each Cartesian quadrant were sampled (n=16/group). Harvested bovine rumen fluid samples within quadrant and group were pooled (n=8, respectively), and bacterial 16S rRNA gene amplicons were sequenced using next-generation sequencing technology. Bacteroidetes and Firmicutes were the dominant phyla in all ruminal groups. The abundances of relative microbial populations and operational taxonomic units did not differ with reference to BW gain and FI, which was supported by no significant changes in diversity or richness. UniFrac principal coordinate analysis did not show any separation of microbial communities within the rumen. The study suggests the limited involvement of the rumen microbiome as a component influencing the efficiency of weight gain at the 16S level, which can be utilized to better understand variations in microbial ecology as well as host factors that will improve feed efficiency.