The rumen contains microorganisms that break down plant matter and supply nutrients to the host animal. Each microorganism has its own set of genes with specific functions. All the genetic information of these rumen microorganisms is collectively known as the rumen metagenome. The composition of the rumen metagenome is known to affect economically important traits like feed intake and gain. The goal of this study was to investigate the influence of the host genome on the composition of the rumen metagenome and identify features of the rumen metagenome that might be useful candidates for future genetic selection. Using data from 717 animals, we focused on 16,350 rumen metagenome features. Of these, 92 features were highly heritable. The composition of the rumen metagenome is affected by multiple host genes. These host genes may affect the rumen metagenome through metabolism or immune processes or even host-microbiome crosstalk. Several features of the rumen metagenome are genetically correlated with production traits. The relative abundance of one feature, the aroD gene, was negatively correlated with average daily dry matter intake and positively correlated with average daily gain making it a possible candidate for the genetic selection of feed efficiency.

Read the full article in the Journal of Animal Science.