Metabolic reconstitution by a gnotobiotic microbiota varies over the circadian cycle

Abstract

Microbiota composition correlates with host metabolic health in both humans and mice. Here we investigated the extent to which a gnotobiotic microbiota can mimic the influence of a complete microbiota on mouse metabolism using an isolator-housed TSE-PhenoMaster® system. We found that energy expenditure was equivalent between germ-free (GF) and specific-opportunistic-pathogen free line (SPF) mice, and we extend this observation to the OligoMM12 microbiota (12 species across 5 phyla that are naturally abundant in a murine gut microbiota). Moreover, microbiota-released calories were well compensated by food intake in all groups. However, each group of mice have a distinctive circadian metabolic profile. OligoMM12 clustered with GF during the light phase, but with SPF during the dark phase for both RER and metabolome. Therefore, interactions between the host and a reductionist microbiota are non-uniform over the circadian cycle, revealing a promising tool to identify key microbiota species/functions that modify host metabolism.

Distinct N and C Cross-Feeding Networks in a Synthetic Mouse Gut Consortium

“…While several members of the OMM consortium produced lactate, no consortium member consumed it. This lack of lactate cross-feeding within the OMM consortium is consistent with the reported higher levels of lactate in the cecum of adult OMM mice than in mice colonized with a specific-pathogen-free microbiome ( 66 ). Overall, our findings show that many crucial metabolic features of the gut microbiota are represented within the OMM consortium and strengthen its relevance as a model for the mouse gut microbiota.…”