PS5-9. Dietary Ginger Root Extract Modulates Intestinal Antimicrobial Peptides and Redox Proteins in Salmonella Infected Broiler Chicks.

Abstract Salmonella infection remains a major challenge in antibiotic-free poultry production, highlighting the need for alternative dietary strategies that support intestinal immune responses and oxidative stress defense. This study evaluated the effect of dietary ginger root extract (GRE) in modulating intestinal antimicrobial peptide and redox gene expression in Salmonella Typhimurium (ST) infected broiler chicks. A total of 400-day-old Ross 708 male broiler chicks were randomly assigned to four treatments: Control (CON) fed a basal corn-soybean diet, CONST (fed a basal corn-soybean diet and challenged with ST, GRE (basal diet + 1.5% ginger root extract), and GREST (Basal diet + 1.5% GRE and challenged with ST). Each treatment consisted of five replicates with 20 birds each. CONST and GREST were orally inoculated with approximately 7.46 × 10⁸ CFU/ml ST on d 2. Growth performance indices: body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR) were recorded over the 14-day experimental period. Ileal tissues were excised on days 7 and 14 to determine expression of oxidative stress genes: Glutathione peroxidase (GPX), Superoxide dismutase (SOD), Nuclear factor erythroid 2-related factor 2 (NRF2), and Catalase (CAT) and avian β-defensin genes (AvBD2, AvBD8, AvBD10) using qRT-PCR. Data generated were analyzed using one-way analysis of variance with treatment as the fixed effect (p < 0.05). Growth indices (BWG, FI and FCR) were similar (p > 0.05) across all groups. On d 7 and 14, GPX, SOD, NRF2, and CAT expressions were upregulated (p < 0.05) in the GREST group except CAT (p = 0.0565), reflecting enhanced intestinal antioxidant defense through activation of key redox-regulating enzymes involved in reactive oxygen species detoxification. A similar trend was observed for antimicrobial peptide genes. Specifically, fold-change values for AvBD2, AvBD8, AvBD10, were upregulated (p < 0.05) in GREST on d 7 and 14 compared with the other treatments (CON, CONST and GRE), thereby suggesting an enhanced innate antimicrobial defense in the intestinal mucosa through increased expression of β-defensins. In conclusion, dietary supplementation of GRE at 1.5% level of the diet promoted upregulation of key antioxidant and antimicrobial defense mechanisms in the ileum of broiler chicks, thus supporting a role for GRE in strengthening intestinal defense against pathogenic infection.