Microbiota populations and short chain fatty acids production in cecum of immunosuppressed broilers consuming diets containing γ-irradiated Astragalus polysaccharides

Abstract This study was designed to evaluate the effects of γ-irradiated Astragalus polysaccharides (IAPS) on growth performance, cecal microbiota populations and concentrations of cecal short chain fatty acids of immunosuppressed broilers. A total of 144 one-day-old broiler chicks were randomly assigned into 3 groups: non-treated group (control), cyclophosphamide (CPM) treated groups fed either a basal diet or the diets containing 900 mg/kg IAPS, respectively. On days 16, 18 and 20, broilers in the control group were intramuscularly injected with 0.5 mL sterilized saline (0.75%, wt/vol), and those in the CPM and IAPS groups were intramuscularly injected with 0.5 mL CPM (40 mg/kg of BW). The trial lasted 21 days. Compared to the control group, CPM treatment decreased the broiler average daily gain (ADG) and feed intake (P 0.05). Dietary IAPS supplementation increased broiler ADG, Shannon index and decreased Simpson index (P