Diversity of gut methanogens in herbivorous animals

Abstract

<jats:p>The digestion of plant biomass by symbiotic microbial communities in the gut of herbivore hosts also results in the production of methane, a greenhouse gas that is released into the environment where it contributes to climate change. As methane is exclusively produced by methanogenic archaea, various research groups have devoted their efforts to investigate the population structure of symbiotic methanogens in the gut of herbivores. In this review, we summarized and compared currently available results from 16S rRNA gene clone library studies, which cover a broad range of hosts from ruminant livestock species to wild ruminants, camelids, marsupials, primates, birds and reptiles. Although gut methanogens are very diverse, they tend to be limited to specific phylogenetic groups. Overall, methanogens related to species of the genus Methanobrevibacter are the most highly represented archaea in the gut of herbivores. However, under certain conditions, archaea from more phylogenetically distant groups are the most prevalent, such as methanogens belonging to either the genus Methanosphaera, the order Methanomicrobiales or the Thermoplasmatales-Affiliated Lineage C Comparisons not only highlight the strong influence of host species and diet in the determination of the population structure of symbiotic methanogens, but also reveal other complex relationships, such as wide differences between breeds, as well as unexpected similarities between unrelated species. These observations strongly support the need for high throughput sequencing and metagenomic studies to gain further insight.</jats:p>

An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production

“…The compound tested in this experiment, 3NOP, is the result of a small molecule inhibitor development program at DSM Nutritional Products (Basel, Switzerland), that started with an in silico virtual screening approach specifically targeting the active site of the methyl CoM reductase (MCR) of Methanobrevibacter ruminantium, one of the most represented methanogenic Archaea in the rumen of domesticated and wild ruminants. Indeed, St-Pierre and Wright (26) reported that although variation in the level of representation of Methanobrevibacter spp. could be observed, depending on ruminant species investigated, diet, and geographical location, the prevalence of these archaeal species in a diverse range of host herbivores worldwide was quite remarkable.…”

Genome sequencing of rumen bacteria and archaea and its application to methane mitigation strategies

“…and Rumen Cluster C (RCC), also known as Thermoplasmatalesaffiliated lineage C but more recently proposed as a seventh order of methanogenic archaea, the 'Methanoplasmatales' (Paul et al, 2012). Remaining groups of methanogens include representatives of the genera Methanosphaera, Methanimicrococccus, Methanosarcina and Methanobacterium (Janssen and Kirs, 2008;St-Pierre and Wright, 2013). In terms of their metabolism, methanogens typically fall into three groups, hydrogenotrophic methanogens that convert H 2 and/or formate to CH 4 and that include members of the genera Methanobrevibacter, Methanomicrobium and Methanobacterium, methylotrophic methanogens that metabolize H 2 plus methyl compounds to CH 4 and that include members of the genera Genome sequencing of rumen bacteria and archaea 237 Methanosphaera, and Methanimicrococcus, together with the RCC organisms, and acetoclastic methanogens that utilize acetate and include members of the genus Methanosarcina.…”

Microbiotes et métagénomique

“…[34][35][36]. Ces espèces qui paraissent minoritaires en nombre, peuvent contribuer à des processus spéci-fiques comme la méthanogenèse, la méthylotrophie, la fixation de l'azote dans les tubes digestifs et les rhizosphères [37][38][39] avec des répercussions majeures sur la nutrition, la croissance de l'hôte ou sur les cycles biogéochimiques [40]. Les microbiotes montrent en général une capacité de résilience remarquable quand ils sont soumis à des perturbations ou des agressions liées à des changements des conditions chez l'hôte ou de paramètres environnementaux [24].…”