PS6-15. Modulation of Intestinal Salmonella Enteritidis Colonization by Dietary Onion Peels in Broiler Chickens.

Abstract Salmonella Enteritidis (SE) remains a major foodborne pathogen of global concern, posing significant risks to poultry production and public health. Onion peel powder (OPP) is rich in polyphenolic compounds that have potential to reduce intestinal Salmonella colonization and support improved growth performance in broiler chickens. The objective of study is to evaluate the efficacy of OPP on SE colonization and growth performance in broiler chickens. Ross 708 (day-old) broiler chicks (n = 500, male) were randomly allocated to five treatments (5 replicates of 20 chicks each) in completely randomized design. Treatments include CON, CONSE (0 g/kg OPP), BMDSE (0.055 g/kg bacitracin methylene disalicylate), OPPXSE (3 g/kg OPP), and OPPYSE (6 g/kg OPP), all fed corn-soybean meal basal diets. All treatments, except CON, were challenged with 1 mL SE (4.80 × 10⁸ CFU/mL) at 2 days of age. On days 2, 5, 12 and 19 post-challenge (PC), cecal lobes were collected for SE enumeration on xylose lysine deoxycholate agar. The birds were weighed on days 5 and 19 PC to evaluate body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR). Data were analyzed by one-way ANOVA using SAS software (P < 0.05). On day 2 PC, chicks in CON were negative for SE, while chicks in SE-challenged treatments had ceca SE concentrations of 4.835 (CONSE), 4.568 (BMDSE), 4.540 (OPPXSE), and 4.402 (OPPYSE) Log10 CFU/g (P > 0.05), thus confirming SE infection in the latter birds. On day 5 PC, chicks in OPPYSE had lower SE (3.185 Log10 CFU/g; P < 0.05) compared to those in CONSE (4.659 Log10 CFU/g). By days 12 and 19 PC, chicks in OPPXSE (1.184 and 0.283 Log10 CFU/g) and OPPYSE (0.586 and 0.108 Log10 CFU/g) had lower (P < 0.05) ceca SE concentrations compared to CONSE chicks (3.879 and 1.983 Log10 CFU/g) respectively. BWG was unaffected (P > 0.05) on days 5 and 19 PC across all treatments, whereas FI was transiently reduced (P < 0.05) in OPP-fed chicks on day 5 PC but remained unchanged by day 19 PC, indicating stable feed consumption during the reduced SE colonization. Moreover, on days 5 and 19 PC, OPP-supplemented treatments showed improved (P < 0.05) FCR relative to other groups, reflecting more efficient nutrient utilization as birds redirected energy toward lowering SE colonization and supporting intestinal health. Overall, OPP supplementation effectively reduced intestinal SE colonization and improved feed efficiency without compromising growth, demonstrating its potential as a functional dietary strategy to enhance intestinal health and performance in broiler chickens.