Abstract
With the global rise in antibiotic resistance, exploring plants for their potential as safe and natural alternatives to antimicrobials in poultry has become increasingly important. The present study aimed to evaluate the ethnoveterinary supplementation of banana peel extract powder (BPP) against Salmonella enterica subspecies enterica serovar Gallinarum biotype Gallinarum (Salmonella Gallinarum), focusing on two key immune-related genes (IL6 and MHC class IIβ), gut morphology, and growth performance of broiler chickens experimentally challenged with Salmonella Gallinarum. A total of 180 day-old Hubbard Classic male chicks were divided into five treatment groups; a non-challenge control (NC), Salmonella Gallinarum infected birds (SGI) and three treatments receiving 2 % (BPP-1), 4 % (BPP-2) and Ciprofloxacin (CIPRO) along with Salmonella Gallinarum challenge. Each treatment was replicated in triplicate, with 36 birds per group. The chicks in challenge groups were orally inoculated on day 7 with 1 mL of 2 × 10⁸ CFU Salmonella Gallinarum, while chicks in NC group received 1 mL of sterile broth. Liver and caecal samples were collected on days 7, 10, 14 and 21 for gene expression analysis of IL6 and MHC class IIβ using qPCR. Histopathological examination of the spleen, liver and caeca was performed on days 10, 14 and 21. Feed intake, feed conversion ratio (FCR) and weight gain were monitored throughout the experiment. Challenge with Salmonella Gallinarum (SGI group) resulted in significantly higher IL-6 expression and lower MHC class IIβ expression (p < 0.01) in both liver and caeca. In contrast, BPP-1 and BPP-2 supplementation led to lower IL-6 with elevated MHC class IIβ expression, indicating a more regulated immune response. In conclusion, dietary supplementation with banana peel, particularly 4 % modulates immune related gene expression (IL6 and MHC class IIβ), improves gut health and growth performance against Salmonella Gallinarum infection in broiler chicks.