Rumen microbial responses to differing nutrient sources

The rumen microbiome is responsible for generating the majority of a ruminant animal's fuel supply and thus largely represents the link between diet inputs and animal outputs. Despite many decades' worth of research, however, the microbiome and its relationship to the host animal's diet lack full characterization. Very few investigations have focused on potential impacts on the microbial communities as influenced by changes in nutrient source. To address this knowledge gap, we investigated how relative abundances of ovine rumen bacterial taxa and estimations of community diversity may be affected by differences in dietary sources of protein and fiber. We observed numerous bacterial population shifts in response to the change in fiber source and also identified an impact on bacterial diversity. The evaluation of microbial sensitivity to differences in protein source identified taxa that have been previously investigated for roles in protein metabolism. We therefore conclude that nutrient source, rather than simply nutrient concentration, may exert a significant impact on bacterial population dynamics. These findings provide another steppingstone on the path to a more comprehensive understanding of the rumen microbiome and how it may be manipulated for optimal animal performance.