Archaeal abundance in post-mortem ruminal digesta may help predict methane emissions from beef cattle

Abstract

Methane produced from 35 Aberdeen-Angus and 33 Limousin cross steers was measured in respiration chambers. Each group was split to receive either a medium- or high-concentrate diet. Ruminal digesta samples were subsequently removed to investigate correlations between methane emissions and the rumen microbial community, as measured by qPCR of 16S or 18S rRNA genes. Diet had the greatest influence on methane emissions. The high-concentrate diet resulted in lower methane emissions (P < 0.001) than the medium-concentrate diet. Methane was correlated, irrespective of breed, with the abundance of archaea (R = 0.39), bacteria (−0.47), protozoa (0.45), Bacteroidetes (−0.37) and Clostridium Cluster XIVa (−0.35). The archaea:bacteria ratio provided a stronger correlation (0.49). A similar correlation was found with digesta samples taken 2–3 weeks later at slaughter. This finding could help enable greenhouse gas emissions of large animal cohorts to be predicted from samples taken conveniently in the abattoir.

The rumen microbial metaproteome as revealed by SDS-PAGE

“…The ruminal archaea are much lower in abundance than bacteria, on average approximately 5% of the bacterial population based on relative abundance of 16S rRNA subunit [17, 39, 40]. Two archaeal proteins were discovered here as dominant spots.…”

Effect of progressive inoculation of fauna-free sheep with holotrich protozoa and total-fauna on rumen fermentation, microbial diversity and methane emissions

“…These correlations have been confirmed using a greater number of animals, R  = 0.38 and 0.49, respectively (Wallace et al. , 2014). These increments in the number of methanogens clearly shows a symbiotic relation between rumen protozoa and methanogens that could enhance the interspecies H 2 transfer (Morgavi et al.…”

Invited review: Large-scale indirect measurements for enteric methane emissions in dairy cattle: A review of proxies and their potential for use in management and breeding decisions

“…Low-CH 4 -emitting microbial communities were associated with higher relative proportions of Fibrobacteres, Quinella ovalis, and other Veillonellaceae such as Selenomononas, in contrast to lower proportions of Ruminococcaceae, Lachnospiraceae, and other Clostridiales (Kittelmann et al, 2014;Wallace et al, 2014;Sun et al, 2015). Fibrobacteres, Quinella, and Selenomononas are broadly known to consume H 2 whereas Ruminococcaceae, Lachnospiraceae, and other Clostridiales produce H 2 during fermentation, and changes in the proportion of these populations would reduce the amount of H 2 available for methanogenesis.…”

“…Fibrobacteres, Quinella, and Selenomononas are broadly known to consume H 2 whereas Ruminococcaceae, Lachnospiraceae, and other Clostridiales produce H 2 during fermentation, and changes in the proportion of these populations would reduce the amount of H 2 available for methanogenesis. In the rumen, these microbial changes are biochemically associated with higher proportions of propionate (Kittelmann et al, 2014;Wallace et al, 2014;Sun et al, 2015).…”