Journal of Animal Science and Veterinary Medicine

Intensive broiler production and rapid growth impose substantial physiological stress on birds, which can predispose them to oxidative stress and immune dysfunction. Vaccine failure and concerns about antimicrobial resistance and residues have increased the need for safer alternative dietary approaches to enhance antioxidant defence and immune function in broiler chickens. This study evaluated the effects of dietary supplementation with Pawpaw Leaf Meal (PLM) and Garlic Powder (GP) on immune response and antioxidant status in broiler chickens during the starter phase. A total of 250 one-day-old unsexed Arbor Acres broiler chicks were randomly allotted to five dietary treatments in a completely randomised design, with five replicates of ten birds each. Birds in Treatments 1 and 2 (positive control and negative control, respectively) received the basal diet without phytogenic inclusion. Other treatments contained 3%PLM, 1%GP and 3% PLM+1%GP, respectively. Birds in Treatment 1 served as the positive control and received routine vaccination against Newcastle and Gumboro diseases, together with coccidiostat medication. Birds in Treatments 2-5 did not receive vaccination or medication throughout the experimental period. At day 21, blood was sampled for the determination of serum cytokines, immunoglobulin A (IgA), antioxidant biomarkers, and total serum protein. Data were analysed using ANOVA at α0.05. Birds fed 3%PLM+1%GP had the highest concentrations of interferon-γ (51.83 pg/mL), interleukin-1β (415.09 pg/mL), interleukin-6 (43.04 pg/mL), total antioxidant capacity (16.94 mM TE) and IgA (338.32 mg/dL), while those fed 3%PLM had the highest serum total protein (45.82 g/L). Birds in the negative control group had the least interferon-γ (23.49 pg/mL), interleukin-1β (177.96 pg/mL), and IgA (167.05 mg/dL), while birds fed 3%PLM had the least interleukin-6 (26.19 pg/mL). Birds in the positive control group had the lowest total antioxidant capacity (7.74 mM TE) and serum total protein (34.44 g/L). In conclusion, dietary inclusion of 3% pawpaw leaf meal and 1% garlic powder enhanced immune response and antioxidant status in broiler chickens during the starter phase, highlighting their potential as natural immunomodulatory feed additives.