Metabolite profiling reveals the interaction of chitin-glucan with the gut microbiota

Julie Rodriguez,Audrey M Neyrinck,Zhengxiao Zhang,Benjamin Seethaler,Julie-Anne Nazare,Cándido Robles Sánchez,Martin Roumain,Giulio G Muccioli,Laure B Bindels,Patrice D Cani,Véronique Maquet,Martine Laville,Stephan C Bischoff,Jens Walter,Nathalie M Delzenne

doi:10.1080/19490976.2020.1810530

Abstract

ABSTRACT Dietary fibers are considered beneficial nutrients for health. Current data suggest that their interaction with the gut microbiota largely contributes to their physiological effects. In this context, chitin-glucan (CG) improves metabolic disorders associated with obesity in mice, but its effect on gut microbiota has never been evaluated in humans. This study explores the effect of a 3-week intervention with CG supplementation in healthy individuals on gut microbiota composition and bacterial metabolites. CG was given to healthy volunteers (n = 15) for three weeks as a supplement (4.5 g/day). Food diary, visual analog and Bristol stool form scales and a “quality of life” survey were analyzed. Among gut microbiota-derived metabolites, bile acids (BA), long- and short-chain fatty acids (LCFA, SCFA) profiling were assessed in stool samples. The gut microbiota (primary outcome) was analyzed by Illumina sequencing. A 3-week supplementation with CG is well tolerated in healthy humans. CG induces specific changes in the gut microbiota composition, with Eubacterium, Dorea and Roseburia genera showing the strongest regulation. In addition, CG increased bacterial metabolites in feces including butyric, iso-valeric, caproic and vaccenic acids. No major changes were observed for the fecal BA profile following CG intervention. In summary, our work reveals new potential bacterial genera and gut microbiota-derived metabolites characterizing the interaction between an insoluble dietary fiber -CG- and the gut microbiota.

Highlights

The nutritional interest of dietary fibers (DF) comes from the recognition of their benefits for health based on a large body of literature
We found only two amplicon sequence variants (ASV) significantly up-regulated by CG inter vention: ASV241 related to the species Roseburia hominis, consistently with the increase of Roseburia genus, and ASV130 belonging to Terrisporobacter genus, which was not impacted by CG
We have shown that 3 weeks of CG intake was well tolerated by healthy subjects, had no effect on gut transit or well-being, and induced significant changes in the gut microbiota composition

Summary

Introduction

The nutritional interest of dietary fibers (DF) comes from the recognition of their benefits for health based on a large body of literature. DF is a category of non-digestible food components that includes lignin, cellulose, resistant starches, nonstarch-polysaccharides, oligosaccharides, and ana logous polysaccharides with associated health benefits.[1] The concept of prebiotics, initially elabo rated with non-digestible oligosaccharides specifi cally fermented by gut bacteria,[2] was recently revisited.[3,4] Prebiotics include fermentable DF which, through their interaction with the gut microbiota, modulate its composition and func tions with beneficial effects for the host. On the basis of studies in animals and humans, it has been proposed that fermentable-prebiotic DF might increase satiety, improve metabolic disor ders, and modulate gut-related immunity through mechanisms related to SCFA influencing endocrine and metabolic functions and intestinal epithelial integrity.[5,6,7,8,9] it remains unclear which are the key health physiological effects generated by insoluble DF, and whether they rely on the gut microbiota

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Results

Conclusion