Dietary nucleotides and yeast extract affect the composition and metabolic activities of the swine gut microbiota in a new in vitro fermentation model

Abstract

Nucleotides (NT) are important compounds to many biological processes but data on the exact role of NT on the gut microbiota remain unclear. In this work we investigated the effects of dietary NT in a medium formulated to simulate the pig ileal chyme on gut microbiota composition and activity using a novel continuous in vitro intestinal fermentation models mimicking the proximal colon. Pig fecal microbiota was immobilized in gellan‐xanthan beads and used as a continuous inoculum in a novel intestinal model platform, operated with multiple parallel reactors to compare treatments on the exact same microbiota composition. Daily effluent samples were collected and analyzed to investigate the composition (qPCR, pyrosequencing) and metabolic activities (HPLC) of the microbiota.We measured significant shifts of microbial diversity, microbiota composition, and activity of effluent samples induced by dietary NT and YE treatments. In particular Lactobacilli (+1.4 Log10) and propionate concentration (+18.7 %) significantly increased in 7.5 g/l high NTYE compare to the control medium. Our data suggest beneficial effects of dietary NT in YE on pig gut microbial balance, associated with enhanced propionate production which could reinforce the barrier effect of the gut microbiota and increased populations of beneficial microbes.This study was supported by a grant from the Worldwide Research Alltech, Inc. in USA.Grant Funding Source: Nutrition (ASN): ASN Graduate Student Research Award Competition, supported by the Nutritional Sciences Council