# Effects of N-Acetylneuraminic Acid on Intestinal Microbial Composition and Metabolic Activity in a Piglet Model

## TL;DR

This study shows that N-acetylneuraminic acid (Neu5Ac) improves gut health in piglets by promoting beneficial bacteria and increasing helpful metabolites like formate and acetate.

## Contribution

The study reveals that coated Neu5Ac enhances intestinal microbial diversity and boosts beneficial metabolites in piglets, offering a new strategy for gut health improvement.

## Key findings

- Neu5Ac increases the colonization of beneficial bacteria like Lactobacillus in piglet intestines.
- Coated Neu5Ac supplementation elevates formate and acetate levels in the jejunum and colon.
- Neu5Ac alters microbial composition, reducing harmful Clostridium and increasing Veillonella and Xylanibacter.

## Abstract

N-Acetylneuraminic acid (Neu5Ac), a major component of human milk oligosaccharides, is abundant in breast milk and plays a critical role in shaping the infant gut microbiota. Nevertheless, the effects of Neu5Ac on microbial composition and metabolic activity in both the small and large intestines during early life are still poorly understood. In this study, we first compared the fermentability and metabolite profiles of five milk-derived monosaccharides (glucose, galactose, fucose, Neu5Ac, and GlcNAc) using in vitro fermentation with piglet jejunal and colonic microbiota. We then examined the effects of dietary coated Neu5Ac supplementation on microbial composition and metabolic activities in the jejunum and colon of piglets. Our results indicate that Neu5Ac promotes the intestinal colonization of beneficial bacteria such as Lactobacillus and increases the production of microbial metabolites, notably formate and acetate, in piglets. These findings indicate that coated Neu5Ac is a promising additive for improving intestinal microbiota homeostasis in piglets.

This study investigates the effects of N-acetylneuraminic acid (Neu5Ac) on intestinal microbial composition and metabolic activity in piglets using two complementary approaches: in vitro fermentation and in vivo dietary supplementation with coated Neu5Ac. In vitro fermentation results demonstrated that Neu5Ac stimulates higher production of formate and acetate by piglet intestinal microbiota compared with other human milk-derived monosaccharides (p < 0.05). In vivo feeding trials showed that dietary coated Neu5Ac significantly increased microbial α-diversity and altered the overall microbial composition in both the jejunum and colon (p < 0.05). For instance, coated Neu5Ac reduced the relative abundances of ASV1 Clostridium and ASV17 Clostridium in the jejunum, while raising the relative abundances of ASV3 Veillonella, ASV4 Veillonella, ASV7 Lactobacillus salivarius, ASV11 Actinobacillus porcitonsillarum in the jejunum, and ASV41 Xylanibacter in the colon (p < 0.05). Furthermore, coated Neu5Ac significantly elevated formate and acetate concentrations in the jejunum (p < 0.05) and exhibited a trend toward increased acetate levels in the colon (0.05 < p < 0.1). Collectively, using piglets as a model, this study demonstrates that Neu5Ac facilitates the intestinal colonization of beneficial microbes (e.g., Lactobacillus), leading to enhanced production of microbial metabolites, particularly formate and acetate, which may contribute to improved gut homeostasis in early life.