Abstract

The human gut can be viewed as a flow-through system with a short residence time, a high turnover rate and a spatial gradient of physiological conditions. As a consequence, the gut microbiota is exposed to highly fluctuating environmental determinants presented by the host and diet. Here, we assessed the fermentation and colonisation of insoluble wheat bran by faecal microbiota of three individuals at an unprecedented sampling intensity. Time-resolved 16S rRNA gene amplicon sequencing, revealed a dynamic microbial community, characterised by abrupt shifts in composition, delimiting states with a more constant community, giving rise to a succession of bacterial taxa alternately dominating the community over a 72 h timespan. Early stages were dominated by Enterobacteriaceae and Fusobacterium species, growing on the carbohydrate-low, protein rich medium to which wheat bran was supplemented. The onset of wheat bran fermentation, marked by a spike in short chain fatty acid production with an increasing butyrate proportion and an increased endo-1,4-β-xylanase activity, corresponded to donor-dependent proportional increases of Bacteroides ovatus/stercoris, Prevotella copri and Firmicutes species, which were strongly enriched in the bran-attached community. Literature and database searches provided novel insights into the metabolic and growth characteristics underlying the observed succession and colonisation, illustrating the potency of a time-resolved analysis to increase our understanding of gut microbiota dynamics upon dietary modulations.

Highlights

  • The human gut harbours an indigenous microbial community characterised by a tremendous inter-individual variability, comprising around 100–160 different species within a single individual [1,2,3,4,5,6]

  • A comparison with the carbohydrate-low medium (Control) in donor 3 showed that wheat bran fermentation already kicked-off after 6 h but became more efficient when the carbohydrate-low medium was depleted after 20 h (Fig. S2)

  • While donor 2 fermented wheat bran initially at a slower rate, after 72 h, the total short chain fatty acid (SCFA) levels produced by donor 2 (69.2 ± 0.6 mM) were similar to donor 1 (70.1 ± 1.2 mM) and higher compared to donor 3 (53.1 ± 1.3 mM) (Fig. 1)

Read more

Summary

Introduction

The human gut harbours an indigenous microbial community characterised by a tremendous inter-individual variability, comprising around 100–160 different species within a single individual [1,2,3,4,5,6]. Most of the research initiatives directed towards the characterisation of this community provide snapshots of the faecal microbiota composition at a single point in time and the knowledge gap on intra-

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call