Synbiotic modulation of adult gut microbiome by 2'-fucosyllactose and Bifidobacterium longum subsp. infantis EFEL8008.

Abstract

Aim: This study aimed to evaluate the combination of 2'-fucosyllactose (2'-FL) and Bifidobacterium longum subsp. infantis (B. infantis) EFEL8008 as a synbiotic pair for adult gut health, using an in vitro digestion and fecal fermentation model. Methods: The resistance of 2'-FL to digestion was evaluated through simulated digestion encompassing oral, gastric, intestinal, and brush border membrane phases. Fecal fermentation was conducted using adult microbiota to investigate taxonomic and metabolic alterations following treatment with 2'-FL, EFEL8008, or their combination. Microbial composition was profiled using 16S rRNA gene sequencing and quantitative PCR targeting B. infantis. Short-chain fatty acids (SCFAs) and trimethylamine (TMA) levels were quantified by ¹H-NMR. Results: A total of 86.67% of 2'-FL remained intact after digestion, demonstrating its resistance to digestion throughout the upper gastrointestinal tract. The synbiotic combination significantly increased Bifidobacterium abundance and improved alpha diversity compared to single treatments. Heat tree and correlation analyses indicated selective enrichment of commensal taxa including Bifidobacterium and Lactobacillus, accompanied by a reduction in the abundance of potentially pathogenic genera such as Escherichia-Shigella. In addition, co-treatment markedly elevated the concentrations of acetate, propionate, lactate, and butyrate, and suppressed the microbial conversion of betaine to TMA, suggesting a favorable metabolic outcome. Conclusion: These results demonstrate that the synbiotic combination of 2'-FL and EFEL8008 promotes beneficial microbial modulation, enhances metabolite production, and supports gut health, highlighting its potential as a next-generation synbiotic strategy.