Dietary alligator pepper powder mitigates thermal stress-induced performance suppression, immune dysfunction, and cellular stress in broiler chickens reared under hot-humid tropical conditions.

This 42-day study investigated the effects of dietary alligator pepper seed powder (ASP) on growth performance, oxidative stress, immune responses, inflammation, and DNA damage in broilers reared under hot-humid tropical conditions. Three hundred and twenty Cobb 500 broilers were randomly assigned to four dietary treatments (8 replicates of 10 birds): control (CTR), vitamin C at 200 mg/kg diet (VTC), ASP at 500 mg ASP/kg diet (AM1), and ASP at 1,000 mg ASP/kg diet (AM2). Final body weight and body weight gain were significantly higher (P = 0.001) in AM2 (3018.95 ± 63.79 g; 2980.05 ± 64.12 g) and VTC (3023.00 ± 59.46 g; 2984.28 ± 59.91 g) compared with CTR, with improved feed conversion ratio (1.47 ± 0.10 vs. 1.61 ± 0.01). Serum corticosterone decreased significantly in AM2 (0.49 ± 0.08 ng/mL) and VTC (0.46 ± 0.12 ng/mL) compared with CTR (1.54 ± 0.06 ng/mL). Antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase) increased, while malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine declined (P < 0.05), suggesting reduced oxidative stress and DNA damage. Immune indices improved in AM2, with higher IgA and IgM levels, reduced pro-inflammatory cytokines (tumor necrosis factor-alpha and interleukin-6), and increased anti-inflammatory cytokines (interleukine-4, interleukin-10). Muscle MDA (P = 0.001) and cholesterol (P = 0.002) were also lowered compared with CTR. In conclusion, dietary ASP at 1,000 mg/kg mitigated heat stress-associated oxidative damage, immune dysregulation, and inflammation, producing responses comparable to vitamin C (200 mg/kg diet). These results highlight ASP as a natural, locally available feed additive capable of enhancing growth, antioxidant status, and immune function in broilers under tropical heat stress.