Supplementation with Agrobacterium sp. FN01-Derived Crude Product Dominated by L-β-Galactoglucan Enhances Growth Performance and Nutrient Utilization and Modulates Intestinal Microbiota in Pigs

Abstract

Simple Summary Polysaccharides play important roles in regulating animal immunity and intestinal health, while their digestive stability and in vivo regulatory effects remain insufficiently clarified. In this study, we characterized a novel water-soluble L-β-galactoglucan isolated from fermented products of soil-originated Agrobacterium sp. FN01 using purified preparations in vitro, and further evaluated the in vivo effects of the corresponding L-β-galactoglucan-dominated crude fermentation product on growth performance, nutrient digestibility, intestinal microbiota, and short-chain fatty acid metabolism in pigs. Supplementation with this crude product improved nutrient utilization by increasing the apparent digestibility of dry matter, crude protein, and other nutrients, increasing average daily gain, and decreasing feed conversion ratio. It also reshaped intestinal microbial composition by improving gut microbial diversity and raising levels of colonic isobutyric acid and isovaleric acid, two typical branched-chain fatty acids produced by intestinal microbial fermentation. In vitro assays showed that L-β-galactoglucan was resistant to hydrolysis by pancreatic α-amylase and glucoamylase. Combined with the in vivo biological responses obtained from the crude product, this material exhibits promising potential as a natural feed additive for swine production.