Abstract
BACKGROUND: Synthetic human milk oligosaccharides (HMOs) are used to supplement infant formula despite limited understanding of their impact on the post-weaned developing gut microbiota. Here, we assess the influence of 0.5 g/L 2-fucosyllactose (2'FL) and 4.0 g/L pooled HMOs (pHMOs) on the composition and activity of cultured fecal-derived microbial communities from seven healthy young children. RESULTS: Exposure to pHMOs induced significant shifts in both the microbial community composition and metabolic output, including an increased abundance of several genera, notably Bacteroides, and the production of health-associated metabolites. In contrast, 2'FL alone did not lead to substantial changes in the communities. A total of 330 bacterial isolates, spanning 157 species, were cultured from these communities and individually evaluated for their responses to HMOs. Over 100 non-Bifidobacterium species showed enhanced growth upon pHMOs treatment and a high degree of intraspecies variation in HMO metabolism was observed. CONCLUSION: Our study provides valuable insight into the health-enhancing properties of HMOs while highlighting the need for future research into the efficacy of incorporating individual structures into infant formula, particularly when aiming to modulate the gut microbiota. Video Abstract.