The antioxidant function of Piper sarmentosum Roxb. alcoholic extract in heat-stressed broilers

This study evaluated the effects of dietary Piper sarmentosum leaf extract (PSE) on the antioxidant capacity, immunity, jejunal morphology, meat quality, and performance of broilers exposed to high ambient temperatures. A total of 240 one-day-old Cobb-500 male broilers were distributed into 20 floor pens and randomly assigned to four dietary treatments with five replicates each (12 birds/replicate). Treatment 1 (TN-control) was fed a basal diet (BD) and kept under thermoneutral conditions. Treatment 2 (HS-control) was fed the BD and exposed to cyclic heat stress (HS) from d 22 to 35. Treatments 3 and 4 were subjected to the same HS regime but were fed the BD supplemented with 100 (PSE100) or 300 (PSE300) mg PSE/kg diet from d 1 to 35. Though growth performance parameters were less affected, the HS-control, compared to the TN-control, exhibited lower IgY levels, reduced antibody titers against Newcastle disease virus (NDV), and decreased activities of catalase (CAT) and glutathione peroxidase (GPx). Heat stress also increased serum malondialdehyde (MDA) concentrations by 8 % and reduced superoxide dismutase (SOD) activity and IgM contents by 8.8 % and 17.6 %, respectively. PSE supplementation effectively reversed these impairments, restoring antioxidant enzyme (CAT, SOD, and GPx) activities and enhancing serum immunoglobulins and NDV antibody titers to levels comparable to or exceeding the TN-control. The results indicate that PSE at an inclusion level of 100 mg/kg serves as an effective natural feed supplement for enhancing antioxidant capacity and immune function in heat-stressed broilers.