The Modulatory Effects of Alfalfa Polysaccharide on Intestinal Microbiota and Systemic health of Salmonella-challenged broilers

Salmonella infection in broilers is a main foodborne illness that substantially threatens food security. This study aimed to examine the effects of a novel polysaccharide isolated from alfalfa (APS) on the intestinal microbiome and systemic health of Salmonella-infected broilers. The results indicated that broilers receiving the APS-supplemented diet had the improved ( P  < 0.05) growth performance and gut health than those fed no APS-supplemented diet. Dietary APS supplementation enhanced ( P  < 0.05) the abundance of Bacteroidetes and reduced ( P  < 0.05) the ratio of Firmicutes to Bacteroidete . Supplementation with APS enhanced ( P  < 0.05) the richness of gut beneficial microbes such as Bacteroidetes , Barnesiella , Parabacteroides , Butyricimonas , and Prevotellaceae , while decreased ( P  < 0.05) the abundance of facultative anaerobic bacteria including Proteobacteri a, Actinobacteria , Ruminococcaceae , Lachnospiraceae , and Burkholderiaceae in the Salmonella -infected broilers. The Bacteroides and Odoribacter were identified as the two core microbes across all treatments and combined with their syntrophic microbes formed the hub in co-occurrence networks linking microbiome structure to performance of broilers. Taken together, dietary APS supplementation improved the systemic health of broilers by reshaping the intestinal microbiome regardless of whether Salmonella infection was present. Therefore, APS can be employed as a potential functional additives to inhibit the Salmonella and enhance the food safety in poultry farming.