# Effects of Dietary Paramylon on Nutrient Digestion and Absorption and Intestinal Health of Weaned Piglets

## TL;DR

This study shows that adding Paramylon, a natural polysaccharide, to piglet diets improves digestion, nutrient absorption, and intestinal health.

## Contribution

The study reveals Paramylon's novel role in enhancing nutrient transport and gut health in weaned piglets.

## Key findings

- Dietary Paramylon improved growth, nutrient digestion, and intestinal morphology in weaned piglets.
- Paramylon upregulated key nutrient transporter genes in the ileum and liver.
- The supplement enriched gut microbiota with Romboutsia and supported amino acid metabolism.

## Abstract

Natural polysaccharides are gaining widespread attention as sustainable and bioactive feed additives. However, the full potential of many novel polysaccharides remains underexplored. This study focused on Paramylon, a unique β-glucan extracted from Euglena gracilis, to explore its broad potential as a functional nutrient. We found that dietary Paramylon significantly enhanced the growth and nutrient digestion of weaned piglets. It improved the structure and function of the intestine, upregulating key transporters for amino acids to facilitate nutrient absorption. This core mechanism was confirmed in both animal and cellular models. Our work demonstrated that Paramylon is an effective polysaccharide that can enhance digestive health and nutrient uptake of weaned piglets, providing a scientific basis for its application as a novel, natural additive to support sustainable animal production.

Weaning stress frequently compromises intestinal integrity and nutrient absorption in piglets and induces structural perturbations in the gut microbiota. This study investigated the effects of dietary Paramylon, a linear β-1,3-glucan from Euglena gracilis, on growth and intestinal function. A total of 32 healthy, 21-day-old weaned piglets (male, castrated, Duroc × Landrace × Yorkshire) were randomly allocated to four groups: control, 0.025%, 0.05%, and 0.1% Paramylon (8 pigs/group). The results showed that 0.05% dietary Paramylon quadratically increased average daily gain and feed intake (p < 0.05). Serum TC content significantly increased, while the serum urea level significantly decreased (p < 0.05). This optimal dose was used for mechanistic exploration. Dietary 0.05% Paramylon notably enhanced ileal morphology, increasing the villus height to crypt depth ratio (p < 0.01) and significantly improving apparent nutrient digestibility and ileal β-amylase activity (p < 0.05). The expression levels of SLC7A1 and GLUT2 in ileum tissues were significantly upregulated (p < 0.05). The expression level of SLC7A7 in the liver was also increased (p < 0.05). This nutrient transport-promoting effect was further confirmed in IPEC-J2 cells, which manifested because 10 ng/mL of pure Paramylon significantly upregulated the gene expressions of SLC38A2, EAAT3, PEPT1, and GLUT2 (p < 0.05). KEGG enrichment analysis on the ileum indicated that differentially abundant metabolites were enriched in amino acid-related metabolic pathways. Furthermore, the 16s sequencing results revealed that Romboutsia was significantly enriched in the Paramylon group. In conclusion, Paramylon, as an effective dietary supplement, helps promote nutrient digestion and absorption in weaned piglets and contributes to maintaining intestinal health.