MOTS-CLES : Ruminal Microbiota ; Bovine ; enteric methane

A group of microbial biomarkers simultaneously associated with bacterial population structure and enteric methane emissions were also identified. These ruminal biomarkers could be used in selection programs as long as they are heritable.

Context and challenges: reducing the impact of ruminants on climate warming must include a reduction in the amounts of enteric methane emissions. Individual differences of emissions were identified amongst cattle. The part of the differences associated with the composition of the ruminal microbiota remains unknown.

Data analysis of the 16S RNA ribosomal sequence of liquid rumen samples from 65 Prim'Holstein cows showed a ruminotype characterized by a lower abundance of Succinivibrionaceae and Methanospaera, a higher abundance of Ruminococcaceae, Christensenellaceae and Lachnospiraceae and by a higher enteric methane emission. A group of microbial biomarkers were also identified as being simultaneously associated with enteric methane emission and the structure of the bacterial community of the rumen. These taxonomic units (OTU) were mainly hydrogen-producing bacteria. They explain up to 24% of the phenotypic variance of methane emissions, whereas the contribution of the host's genome was approximately 14%. 

These biomarkers could be used as part of a selection program targeting methane reduction on dairy farms, as long as they are heritable.