Targeted induction of gut-microbial metabolism acutely affects feeding patterns and clock gene expression in the host

The gut microbiota and host diurnal rhythm mutually influence each other, and microbiota metabolism has been shown to play a role in regulating host circadian function via secretion of fermentation products. Microbial metabolism is dependent on the availability of nutrients for the microbiota, typically through the hosts food intake, making it challenging to disentangle the effect of host and microbiota metabolism. In this study, we acutely induced gut microbial metabolic activity without inducing host metabolism in mice. We found that increasing microbial metabolism in the gut altered clock gene expression locally. Actuating microbiota metabolism also reduced host food intake beyond the calories provided by the microbiota, suggesting a systemic signaling effect of microbial metabolism on the host.