Development of a synbiotic dietary supplement containing potential Next Generation Probiotics for modulation of the gut microbiome and metabolome

The term Next Generation Probiotics (NGPs) refers to microbial strains positively impacting on human health, but do not belong to common probiotic species (e.g., lactic acid bacteria, LAB). We characterized genomically and phenotypically 14 strains isolated from the gut microbiome of healthy individuals, to evaluate their ability to produce urolithins, equol and short-chain fatty acids (SCFA). The 4 most promising strains (namely <i>Bacteroides uniformis</i> A4, <i>Bacteroides thetaiotaomicron</i> A14, unclassified <i>Bacteroidaceae</i> A26 and unclassified <i>Lachnospiraceae</i> A49) were used for the production of a synbiotic formulation, containing the strains and the precursors of health-promoting molecules. This dietary supplement was administered for 2 weeks to a continuous mucosal-Simulator of the Human Intestinal Microbial Ecosystem (mSHIME) model inoculated with a faecal sample from a low fiber-consuming donor. We performed Shotgun Metagenome Sequencing on a total of 204 samples collected from lumen and mucosa compartments, and determined the concentration of SCFA, equol and urolithin. Our results highlighted that the potential NGP strains contained in the supplement persisted in the gut ecosystem during 2 weeks of washout (Wilcoxon's rank sum test, p-value <0.05). In addition, the treatment led to an enrichment in beneficial taxa and to an increase in the production of SCFAs (p-value <0.05). This study demonstrated that feeding the gut microbiota with NGPs and dietary prebiotics can modulate both the gut microbiome and metabolome, suggesting a potential beneficial impact on human health. However, further <i>in vivo</i> studies are needed to confirm these results.