Comparative Analysis of Fucosyllactose-Induced Changes in Adult Gut Microbiota and Short-Chain Fatty Acid Production Using the Simulator of Human Intestinal Microbial Ecosystem Model

As the third most abundant solid component of human milk, human milk oligosaccharides (HMOs) exert well-known effects on the infant gastrointestinal tract, including promoting <i>Bifidobacterium</i> growth and preventing pathogen infection. However, the effects of HMOs on the adult gut microbiome remain unknown. In this study, we examined the effects of 2'-fucosyllactose (2'-FL) and 3-fucosyllactose (3-FL), the most abundant HMOs, on the adult gut microbiome using the Simulator of Human Intestinal Microbial Ecosystem (SHIME^Ⓡ), which can simulate human gastrointestinal conditions. Healthy adult feces were subjected to SHIME^Ⓡ and incubated with either 2'-FL or 3-FL. The changes in the short-chain fatty acid concentration in feces and the gut microbiota composition were investigated using high-performance liquid chromatography and 16S rRNA gene sequencing, respectively. The addition of 2'-FL or 3-FL altered the microbial composition and increased acetate, propionate, and butyrate concentrations in the adult SHIME^Ⓡ culture. Remarkably, a difference was observed in the timing of butyrate production because of the addition of 2'-FL and 3-FL. The present findings can help clarify how FLs affect the gut microbiome of Japanese adults and support the development of targeted products.