Selenium Broussonetia papyrifera polysaccharide alleviated cyclophosphamide-induced immune suppression, growth inhibition, intestinal damage, and gut microbiota disorder in yellow-feather broilers.

This study aims to investigate the effects of selenium Broussonetia papyrifera polysaccharide (Se-BPP) on growth performance, immune regulation, intestinal barrier function, and gut microbiota in cyclophosphamide (CTX)-induced immunosuppressed chicks. A total of 120 one-day-old male yellow-feathered broilers were randomly divided into five groups: normal control group (NC), model control group (MC), low-dose Se-BPP group (Se-L), high-dose Se-BPP group (Se-H), and Astragalus polysaccharide (APS) group The Se-L and Se-H groups were supplemented with 0.1 % or 0.2 % Se-BPP, respectively, while the APS group was supplemented with 0.2 % APS. On days 22, 24, and 26, the NC group received intramuscular injections of 80 mg/kg saline, while the other groups received the same dose of CTX to induce immunosuppression in the chicks. The results showed that CTX caused growth retardation, immunosuppression, intestinal damage, and alterations in gut microbiota structure. Supplementation with Se-BPP improved average daily gain and reduced feed-to-gain ratio, promoting growth in immunosuppressed chicks. Se-BPP increased the immune organ index and serum content of IgG, IgM, IgA, SOD, GSH-Px, CAT, IL-2, IL-4, IL-6, IL-10, and INF-γ, thus alleviating the immunosuppression and oxidative stress caused by CTX. Additionally, Se-BPP enhanced the mRNA expression levels of ZO-1, Claudin 1, and MUC2 and increased villus height in the jejunum, effectively mitigating intestinal damage induced by CTX. Although the effect of Se-BPP on alpha diversity of the gut microbiota was not significant, it increased the abundance of beneficial bacteria such as Ruminococcus and Lactobacillus. In brief, this study demonstrated that adding Se-BPP to the diet could improve immunosuppression, intestinal damage, and microbiota disturbances in yellow-feather broiler chickens challenged with CTX, enhancing their production performance.