Lower methane emissions were associated with higher abundance of ruminal Prevotella in a cohort of Colombian buffalos

Abstract

Background Ruminants burp massive amounts of methane into the atmosphere and significantly contribute to the deposition of greenhouse gases and the consequent global warming. It is therefore urgent to devise strategies to mitigate ruminant’s methane emissions to alleviate climate change. Ruminal methanogenesis is accomplished by a series of methanogen archaea in the phylum Euryarchaeota, which piggyback into carbohydrate fermentation by utilizing residual hydrogen to produce methane. Abundance of methanogens, therefore, is expected to affect methane production. Furthermore, availability of hydrogen produced by cellulolytic bacteria acting upstream of methanogens is a rate-limiting factor for methane production. The aim of our study was to identify microbes associated with the production of methane which would constitute the basis for the design of mitigation strategies. Results Moderate differences in the abundance of methanogens were observed between groups. In addition, we present three lines of evidence suggesting an apparent higher abundance of a consortium of Prevotella species in animals with lower methane emissions. First, taxonomic classification revealed increased abundance of at least 29 species of Prevotella. Second, metagenome assembly identified increased abundance of Prevotella ruminicola and another species of Prevotella. Third, metabolic profiling of predicted proteins uncovered 25 enzymes with homology to Prevotella proteins more abundant in the low methane emissions group. Conclusions We propose that higher abundance of ruminal Prevotella increases the production of propionic acid and, in doing so, reduces the amount of hydrogen available for methanogenesis. However, further experimentation is required to ascertain the role of Prevotella on methane production and its potential to act as a methane production mitigator.

Starvation Alters Gut Microbiome in Black Soldier Fly (Diptera: Stratiomyidae) Larvae

“…Although methane emission was not measured in this study, the high relative abundance of methanogenic archaea in the Fed group at T0 and T24 H is interesting, especially with regards to several reports of low methane emission rates by black soldier fly larvae ( Mertenat et al, 2019 ; Pang et al, 2020 ; Parodi et al, 2020 ). Indeed, differences in methanogen abundance would affect methane production, but it remains also possible that differences in microbial composition and functioning that result in perturbation of hydrogen metabolism or accumulation may also impact methanogenesis and methane emissions ( Sugimoto et al, 1998 ; Sollinger et al, 2018 ; Aguilar-Marin et al, 2020 ). Notwithstanding, the higher relative abundance of Methanomicrobiales in the black soldier fly larval microbiomes within the early timepoints of the Fed group could be an indication of the reduced gut environment, as well as conditions of the external (i.e., fresh substrate with very little frass) and consumed substrate (i.e., within the gut), including mixed alcohol and other products resulting from digestion and fermentation of plant polymers ( Lurie-Weinberger and Gophna, 2015 ; Moissl-Eichinger et al, 2018 ).…”

Alternative pathways for hydrogen sink originated from the ruminal fermentation of carbohydrates: Which microorganisms are involved in lowering methane emission?

“…Interestingly though, a study reported that early and late lactation stages were correlated with different levels of CH 4 emissions not accompanied by changes in the rumen microbiome [80]. In a study with Colombian buffalos, the genus Prevotella was associated with low CH 4 emissions [81]. Despite the differences reported in archaea composition between buffalo and cattle [82], this bacterial group seems relevant for CH 4 emission of both species.…”

“…Despite the differences reported in archaea composition between buffalo and cattle [82], this bacterial group seems relevant for CH 4 emission of both species. As some authors pointed, the host genotype affects the phenotype of CH 4 emission, in addition to its microbial community [81]. Indeed, one study indicated that H 2 -producing bacteria explained up to 24% of CH 4 phenotypic variance, and host genome, 14% [70].…”

Regulation of Dietary Protein Solubility Improves Ruminal Nitrogen Metabolism In Vitro: Role of Bacteria–Protozoa Interactions

“…P. ruminicola has the greatest range and activity of dipeptidyl peptidases, which release dipeptides from the N-terminus of peptides [ 43 ] and may be the main reason for the higher substrate N digestibility in S30 and S40 and also the strong positive correlation of this microbe with ND ( Figure 5 B). A recent study [ 44 ] showed that lower methane emissions and higher feed conversion efficiency were associated with a higher abundance of P. ruminicola , which was also validated from the results that substrates DMD and ND were increased in S30 and S40, while methane production requires subsequent experiments to verify. Furthermore, it was observed that the abundance of Fibrobacter_succinogenes ( F. succinogenes ), which is considered to be a key cellulolytic bacterium that promotes the metabolism of other microbiota members by degrading cellulose into soluble sugars and succinate [ 45 ], was up-regulated in S30 and S40.…”