Gut microbiome response to a fermented milk product in healthy subjects. Tolerance study

Although many clinical studies have been conducted to evaluate the effect of probiotics, there are limited studies that assessed the dose-response effects of probiotics on microbiota and host. In this context, a novel multi-strain fermented dairy product was developed (Test product), combining yogurt strains (Streptococcus thermophilus and Lactobacillus bulgaricus) and three candidate probiotic strains, Lactobacillus paracasei subsp. paracasei CNCM I-1518 and CNCM I-3689 and Lactobacillus rhamnosus CNCM I-3690 selected for their effects on gut barrier function and/or gut microbiota or immunity in various models. In the present study, we conducted a 4-week intervention, randomised, double-blind, controlled clinical trial to assess the tolerance of daily ingestion of one or three doses of the Test product in 96 healthy adults. We explored the structural and functional response of gut microbiota to intervention, and following discontinuation. Using shotgun metagenomic, we explored the KEGG orthologs that were carried by 3 probiotic candidate strains and their co-variation interactions with gut microbial species through metabolic sharing.