Spirulina platensis and β-glucan mitigate cyclophosphamide-induced Immunosuppression in broilers: Differential effects of preventive and therapeutic strategies via redox-inflammatory modulation.

Immunosuppression remains a major constraint in intensive poultry production, compromising growth performance and increasing susceptibility to disease. This study investigated the comparative preventive and therapeutic efficacy of dietary Spirulina platensis and β-glucan in broiler chickens subjected to cyclophosphamide-induced immunosuppression. A total of 240 one-day-old Sasso broiler chicks were casually allotted into six experimental groups (n = 40/group; 4 replicates of 10 birds). Treatments included a control, a cyclophosphamide-treated group, and groups supplemented with Spirulina or β-glucan in either preventive or therapeutic regimens. Growth performance, lymphoid organ indices, hematological parameters, phagocytic activity, oxidative stress biomarkers, inflammatory gene expression, and histopathological alterations were evaluated on days 21 and 28. Cyclophosphamide administration significantly impaired growth performance, reduced lymphoid organ indices, suppressed leukocyte counts and phagocytic activity, and induced oxidative stress, as evidenced by augmented malondialdehyde levels and reduced glutathione content and catalase activity. These changes were accompanied by upregulation of nuclear factor kappa B (NF-κB) and downregulation of interleukin-10 (IL-10) expression in lymphoid tissues. Dietary supplementation with Spirulina or β-glucan significantly ameliorated these adverse effects, restoring growth performance, enhancing immune function, improving antioxidant status, and modulating inflammatory responses. Histopathological examination confirmed marked recovery of lymphoid tissue architecture, with more pronounced improvements observed under preventive supplementation.In conclusion, Spirulina platensis and β-glucan effectively mitigate cyclophosphamide-induced immunosuppression in broiler chickens, with preventive administration providing superior protection. These findings support their application as functional feed additives to enhance immune competence and productivity in poultry production systems.