Diurnal feeding behaviour drives 24h rhythms within intestinal epithelial cells and the gut microbiome
Gut function exhibits 24h (circadian) rhythmicity, in part driven by intrinsic clocks within intestinal epithelial cells (IECs).  The gut microbiome exhibits 24h rhythms in composition and function, which are important for maintenance of metabolic and immune health.  We determined the influence of feeding behaviour on the colonic circadian landscape using an interval feeding paradigm, whereby food intake was partitioned equally across the 24h day.  RNAseq analysis revealed that the IEC cell intrinsic clock persists in the absence of diurnal feeding rhythms, however a subset of transcripts lose rhythmicity, demonstrating that feeding driven cell extrinsic temporal cues contribute significantly to maintenance of the rhythmic gut transcriptome.   Interval fed mice lost rhythmicity in secretory IgA and within the microbiota and microbial derived short chain fatty acids.  This work highlights the importance of daily rhythms in feeding behaviour for maintenance of rhythmic processes within the gut, with implications for metabolic and immune health.