Administration of Bifidobacterium animalis subsp. lactis Strain BB-12 in Healthy Children: Characterization, Functional Composition, and Metabolism of the Gut Microbiome of Healthy Children

Background: The effects of probiotic Bifidobacterium animalis subsp. lactis strain BB-12 (BB-12) in children ages one to five are unclear. Consumption of probiotics may influence the hosts' gut microbiome and metabolome, which may reflect shifts in gut microbial diversity composition and metabolism. These changes might have a beneficial impact on health, including protection against antibiotic-related diarrhea and gastrointestinal disorders.Objective: To examine the potential impact of a two strain (Streptococcus thermophilus and Lactobacillus delbrueckii) supplemented yogurt (S2) vs. S2 and BB12 supplemented yogurt (S2+BB12) in gut microbiome and metabolome on healthy children.Design, Setting, and Participants: Included in this study were 59 participants aged one to five years recruited to phase I of a double-blinded, randomized controlled trial (protocol NCT001652287). Fecal samples (n = 169) were collected at baseline, ten, and 20 days after probiotic consumption.Intervention: Participants were given a yogurt with two strains of probiotic (S2; n = 31) or BB12-supplemented three strain yogurts (S2+BB12; n = 29) for ten consecutive days.Main Outcomes and Measures: Untargeted metabolomic profiling and shotgun metagenomics were performed on fecal samples at baseline, ten days after probiotic consumption, and 20 days after probiotic discontinuation.Results: Shotgun metagenomics and metabolomic analyses didn't reveal global changes in gut microbiome or metabolome. Probiotics' increase was observed in the S2+BB12 group compared to S2 group.Conclusion and Relevance: There are few studies investigating the effect of probiotics in early ages (one to five years old) on gut microbiome and metabolome, and therefore their effect is still unclear. Untargeted metabolomics and metagenomic analyses have been used on fecal samples in this double-blinded, randomized controlled trial to observe gut microbiome and metabolome changes when administered two (S2) vs. three (S2+BB12) strains of probiotics in healthy children for ten consecutive days. Gut microbiome and metabolome in this cohort showed overall microbial and functional stability, even if the addition of BB12 caused the increase of other probiotic strains belonging to Lactobacillus and Bifidobacterium genera.