# An in vitro batch culture study to assess the fermentation of human milk oligosaccharides by faecal microbiota from healthy and irritable bowel syndrome stool donors

## TL;DR

This study tested how human milk oligosaccharides affect gut bacteria in healthy people and those with IBS, finding that certain combinations may help improve gut health in IBS patients.

## Contribution

The study identifies specific HMO combinations that may be most effective in modulating gut microbiota and organic acid production in IBS patients.

## Key findings

- IBS donors had distinct microbial profiles and lower organic acid levels compared to healthy controls.
- HMO interventions increased Bifidobacterium, Faecalibacterium, and organic acid production in IBS donor samples.
- A 3’SL/LNT HMO mix showed the most promising effects for IBS patients.

## Abstract

This study explored the effects of different human milk oligosaccharides (HMOs), solely and in combination, on gut microbiota composition and metabolic activity (organic acid production), using anaerobic in vitro batch culture fermenters. The aim was to compare prebiotic effects of HMOs (2’FL, 3’FL, 3’SL, 6’SL, LNT, LNnT, and 1:1 ratio mixes of 2’FL/3’SL and 3’SL/LNT) in faecal samples from irritable bowel syndrome (IBS) donors and healthy controls, and to determine the best-performing HMO in IBS. Fluorescent in situ hybridisation coupled with flow cytometry was utilised to study microbiota changes in major colonic genera, and organic acid production was assessed by gas chromatography. IBS donors had different starting microbial profiles compared to healthy controls and lower levels of organic acids. In response to HMOs, there were alterations in both the control and IBS faecal microbiomes. In IBS donor fermenters, Bifidobacterium, Faecalibacterium, total bacterial numbers, and organic acid production significantly increased post-HMO intervention. When comparing the effect of HMO interventions on the microbiota and organic acid production, a mix of 3’SL/LNT HMOs may be the most promising intervention for IBS patients.