Prebiotics inhibit proteolysis by gut bacteria in a host diet-dependent manner: a three-stage continuous in vitro gut model experiment

Wang, X., Gibson, G. R. ORCID: https://orcid.org/0000-0002-0566-0476, Sailer, M., Theis, S. and Rastall, R. A. (2020) Prebiotics inhibit proteolysis by gut bacteria in a host diet-dependent manner: a three-stage continuous in vitro gut model experiment. Applied and Environmental Microbiology, 86 (10). e02730-19. ISSN 0099-2240 doi: 10.1128/AEM.02730-19

Abstract/Summary

Dietary protein residue can result in microbial generation of various toxic metabolites in the gut, such as ammonia. A prebiotic is “a substrate that is selectively utilised by host microorganisms conferring a health benefit” (G. R. Gibson, R. Hutkins, M. E. Sanders, S. L. Prescott, et al., Nat Rev Gastroenterol Hepatol 14:491–502, 2017, https://doi.org/10.1038/nrgastro.2017.75). Prebiotics are carbohydrates that may have the potential to reverse the harmful effects of gut bacterial protein fermentation. Three-stage continuous colonic model systems were inoculated with fecal samples from omnivore and vegetarian volunteers. Casein (equivalent to 105 g protein consumption per day) was used within the systems as a protein source. Two different doses of inulin-type fructans (Synergy1) were later added (equivalent to 10 g per day in vivo and 15 g per day) to assess whether this influenced protein fermentation. Bacteria were enumerated by fluorescence in situ hybridization with flow cytometry. Metabolites from bacterial fermentation (short-chain fatty acid [SCFA], ammonia, phenol, indole, and p-cresol) were monitored to further analyze proteolysis and the prebiotic effect. A significantly higher number of bifidobacteria was observed with the addition of inulin together with reduction of Desulfovibrio spp. Furthermore, metabolites from protein fermentation, such as branched-chain fatty acids (BCFA) and ammonia, were significantly lowered with Synergy1. Production of p-cresol varied among donors, as we recognized four high producing models and two low producing models. Prebiotic addition reduced its production only in vegetarian high p-cresol producers.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/91073
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences > Food Microbial Sciences Research Group
Publisher	American Society for Microbiology
Download/View statistics	View download statistics for this item