Investigating the effect of two methane-mitigating diets on the rumen microbiome using massively parallel sequencing

Area of Science:

• Animal Science
• Microbiology
• Environmental Science

Background:

• Rumen microbiome composition in dairy cattle influences methane emissions.
• Feed additives are explored to mitigate enteric methane production.

Purpose of the Study:

• To investigate the impact of two methane-mitigating feed additives on the rumen and fecal microbiome profiles of Holstein dairy cattle.
• To identify microbial biomarkers associated with reduced methane production.

Main Methods:

• Untargeted shotgun sequencing of rumen fluid to generate quantitative microbiome profiles.
• Analysis using linear mixed modeling, hierarchical clustering, and metagenomic predictions.
• Differential representation analysis of microbial contigs.

Main Results:

• Both feed additives significantly altered rumen microbiome profiles.
• Fecal microbiome alterations were subtle but detectable via specific analytical methods.
• Differentially represented microbial contigs showed overlap between additive treatments.
• These contigs were enriched for associations with lower methane production in an independent animal cohort.

Conclusions:

• Methane-mitigating feed additives modify the rumen microbiome composition in dairy cattle.
• The identified microbial contigs, including new Faecalibacterium spp., serve as potential biomarkers for low-methane-emitting cattle.