Title: Changes in the rumen microbiome from steers differing in feed efficiency Authors
Submitted to: American Society for Microbiology General Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 21, 2014
Publication Date: May 17, 2014
Citation: Myer, P.R., Freetly, H.C., Smith, T.P. 2014. Changes in the rumen microbiome from steers differing in feed efficiency [abstract]. American Society for Microbiology 114th General Meeting. Poster No. 1292. Technical Abstract: The cattle rumen has a diverse microbial ecosystem that is essential to allow the host to digest plant material. Changes in the composition and diversity of the ruminal microbiota have been associated with diet and age. 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). The result was a 2 X 2 factorial design consisting of high and low feed intake, and high and low BW gain. At the end of the feeding period, steers were harvested, and rumen fluid was sampled and strained with 4 layers of cheesecloth. Samples within quadrant and group were pooled (n=8, respectively), and bacterial 16S rRNA gene amplicons were then determined using next-generation sequencing technology. Firmicutes and Bacteroidetes were the dominant phyla in all ruminal groups. The abundances of relative microbial populations differed with reference to BW gain and FI. UniFrac analysis showed microbial communities in the rumen with differences in BW gain and FI. The study suggests the involvement of the rumen microbiome as a component influencing the efficiency of weight gain, which can be utilized to better predict variations in microbial ecology as well as host factors that will improve feed efficiency.