Regulation of Isoleucine on Colonic Barrier Function in Rotavirus-Infected Weanling Piglets and Analysis of Gut Microbiota and Metabolomics

Abstract

Rotavirus (RV) is a significant contributor to diarrhea in both young children and animals, especially in piglets, resulting in considerable economic impacts on the global pig industry. Isoleucine (Ile), a branched-chain amino acid, is crucial for regulating nutrient metabolism and has been found to help mitigate diarrhea. This study aimed to assess the impact of isoleucine supplementation in feed on colonic barrier function, colonic microbiota, and metabolism in RV-infected weanling piglets. A total of thirty-two weaned piglets, aged 21 days, were randomly assigned to two dietary groups (each further divided into two subgroups, with eight replicates in each subgroup), receiving diets with either 0% or 1% isoleucine for a duration of 14 days. One group from each treatment was then challenged with RV, and the experimental period lasted for 19 days. The results showed that dietary Ile significantly increased the secretion of IL-4, IL-10, and sIgA in the colon of RV-infected weanling piglets (p < 0.05). In addition, Ile supplementation notably increased the expression of tight junction proteins, including Claudin-3, Occludin, and ZO-1 (p < 0.01), as well as the mucin protein MUC-1 in the colon of RV-infected weanling piglets (p < 0.05). Gut microbiota analysis revealed that dietary Ile increased the relative abundance of Prevotella and decreased the relative abundance of Rikenellaceae in the colons of RV-infected weanling piglets. Compared with the RV+CON, metabolic pathways in the RV+ILE group were significantly enriched in vitamin digestion and absorption, steroid biosynthesis, purine metabolism, pantothenate and CoA biosynthesis, cutin, suberine, and wax biosynthesis, as well as fatty acid biosynthesis, and unsaturated fatty acid biosynthesis. In conclusion, dietary Ile supplementation can improve immunity, colonic barrier function, colonic microbiota, and colonic metabolism of RV-infected weaned piglets. These findings provide valuable insights into the role of isoleucine in the prevention and control of RV.

Keywords: gut microbiota; intestinal barrier; isoleucine; metabolomics; piglets; rotavirus.

Figure 1

Timeline of the events in the experimental study.

Figure 2

The histological structure of the colon in RV-infected weaned piglets (HE, 200×). (A) The RV-CON group, (B) the RV-Ile group, (C) the RV+CON group, and (D) the RV+Ile group. Bar = 200 μm.

Figure 3

Effect of isoleucine on the expression of colonic tight junction protein, defensin and mucin protein in weaned Piglets. The proteins expression of Claudin 3 (A), Occludin (B), MUC-1 (C) and ZO-1 (D), respectively, in colon of RV-infected piglets. Data are presented as the mean ± S.D, * p < 0.05; ** p < 0.01.

Figure 4

Principal coordinate analysis (A) and non-metric multidimensional scaling analysis (B).

Figure 5

Taxonomy. Phylum-level (A) and genus-level (B) taxonomic distribution of gut microbiota.

Figure 6

Bioinformatics analysis of the metabolomics. (A) The volcano plot of differential metabolites between the RV-ILE group and the RV-CON group. (B) The volcano plot of differential metabolites between the RV+ILE group and the RV+CON group. (C) KEGG analysis of the differential metabolites between the RV-ILE group and the RV-CON group. (D) KEGG analysis of the differential metabolites between the RV+ILE group and the RV+CON group.