Dietary Melegueta pepper alleviates heat stress-induced disruptions in haematobiochemical parameters, liver histopathology and growth performance indices of broiler chickens in tropical conditions.

This study investigated the effects of Melegueta pepper seed powder (MSP) on haematobiochemical indices, liver histopathology, and growth performance of broiler chickens under tropical heat stress. A total of 320 Cobb 500 chicks were assigned to four diets: basal diet (TRT1), basal + vitamin C (200 mg/kg; TRT2), basal + 0.5 g/kg MSP (TRT3), and basal + 1.0 g/kg MSP (TRT4). Ambient temperatures ranged between 28.9 °C and30.9 °C, with the Temperature-Humidity Index ranging from 28.5 to 30.8. Compared with TRT1, TRT2 and TRT4 recorded higher red blood cell counts (3.08 and 3.07 × 10¹²/L vs. 2.31 × 10¹²/L), haemoglobin concentrations (11.08 and 11.26 g/dL vs. 9.81 g/dL), and packed cell volumes (33.25% and 33.77% vs. 29.41%). Total protein (35.36 and 34.04 g/L vs. 28.48 g/L) and albumin (15.27 and 14.87 g/L vs. 9.90 g/L) increased, while AST (49.08 and 51.98 IU/L vs. 63.54 IU/L), ALT (16.11 and 17.09 IU/L vs. 29.34 IU/L), and creatinine (45.53 and 47.07 µmol/L vs. 67.75 µmol/L) decreased in supplemented groups. Histopathology revealed pronounced periportal inflammation in TRT1, mild lesions in TRT3, and normal hepatic structure in TRT2 and TRT4. Production efficiency factor was highest in TRT2 (494.52) and TRT4 (457.12) compared with TRT1 (358.78) and TRT3 (346.15), with similar trends for weekly relative growth rate (10.37% and 10.36% vs. 9.86% and 10.02%, respectively). MSP at 1.0 g/kg provided haematoprotective, hepatoprotective, and performance-enhancing benefits comparable to vitamin C under tropical heat stress.