# The effect of omega-3 polyunsaturated fatty acids on short-chain fatty acid production and the gut microbiome in an in vitro colonic fermentation model

## TL;DR

Omega-3 fatty acids boost short-chain fatty acid production in the gut, especially when combined with inulin, in an in vitro model.

## Contribution

Demonstrates prebiotic-like activity of omega-3 PUFAs in promoting SCFA synthesis when combined with inulin.

## Key findings

- Omega-3 PUFAs increased total SCFA concentration by 9.3% without inulin and 19.3% with inulin.
- Omega-3 PUFAs increased Bifidobacteriaceae abundance when combined with inulin.
- Prebiotic activity of omega-3 PUFAs is enhanced by the presence of soluble fibre inulin.

## Abstract

Oral administration of omega-3 polyunsaturated fatty acids (PUFAs) to rodents and humans is associated with an increase in gut bacteria that are predicted to synthesise short-chain fatty acids (SCFAs). We tested the hypothesis that physiological levels of omega-3 PUFAs in the distal intestinal lumen (1–50 μg/mL) are associated with increased SCFA synthesis in an in vitro fermentation model using faecal slurry from 10 healthy participants (mean age 30 years), with and without exogenous dietary fibres. SCFAs were measured by gas chromatography-flame ionisation detection (n = 10), and changes in bacterial composition were analysed by shotgun metagenomic sequencing (n = 6). In the presence of omega-3 PUFAs, there was a mean 9.3% (no inulin; P = 0.03) and 19.3% (+ 0.01 mg/mL inulin; P = 0.01) increase in total SCFA concentration at 24 h compared with paired control fermentations. Omega-3 PUFAs had a limited effect on the fermentation model microbiome in the absence of inulin. However, omega-3 PUFAs (50 μg/mL) were associated with increased abundance of Bifidobacteriaceae compared with paired control fermentations, if inulin (0.01 mg/mL) was present. Prebiotic activity of omega-3 PUFAs drives SCFA synthesis in an in vitro colonic fermentation model and is augmented by the soluble fibre inulin.