Dietary arabinogalactan modulates immunity and improves gut barrier in broilers via regulating metabolome and gut microbiome

Abstract

The extraction of polysaccharides from wood by-products is recognized as a green re-utilization approach to shape a recycling-oriented society. In this research, we identified the structural properties of arabinogalactan (AG) extracted from Larix sibirica Ledeb wood chips and verified its efficacy as an additive in broiler framing. Results showed that the molecular weight of AG is 19.805 KDa. Methylation analysis and NMR spectra indicate that AG has a 1,6-linked Galp backbone, side residues mainly branched at C-1,3,6 on β-D-Galp. The Ara residues were substituted at C-3 of 1,6-linked Galp consisting of α-L-Araf-(1→3)-α-L-Araf-(1 → 3)-α-L-Araf (1→ and α-L-Araf-(1 → 4) β-D-Galp-(1 → 3)-β-D-Galp-(1→. As a dietary supplement in broiler model, AG treatment improved the body weight of broilers especially breast and leg muscle weight. Furthermore, AG could regulate host immune response, gut microbiota composition, and metabolic activity, especially promoting lipid metabolism. By means of serum non-targeted metabolomics analysis, enrichment of pantothenate and CoA biosynthesis and beta-alanine metabolism pathways could be determined. AG treatment led to a rise in bacteria that produce SCFAs, with elevated concentrations of acetic and butyric acids. In conclusion, AG can be considered as a potential dietary supplement to beneficially affect host's health status.