20.500.12556/RUL-177787 Administration route and trial repetition shape the effects of a commercial synbiotic on broiler production performance, cecal microbiota and pathogen colonization Campylobacter and Salmonella are leading causes of foodborne bacterial enteritis, with poultry meat being an important source. This longitudinal field study evaluated the impact of the commercial synbiotic PoultryStar, administered via water or feed, on broiler production performance, gut colonization with Campylobacter jejuni and Salmonella Infantis, and cecal microbiota. Two large food business operators were included in the study, with two independent trials conducted at each. A significantly higher European efficiency factor was observed when synbiotic was supplemented in water rather than in feed, although the effect did not differ from the control group. Body weight also tended to increase with synbiotic supplementation in water, although the effect was inconsistent across farms. Feed supplementation significantly reduced colonization of broilers with S. Infantis, whereas no effect was observed regarding C. jejuni. However, two bacterial taxa potentially contributing to the colonization resistance against C. jejuni were identified, belonging to the genus Lactobacillus and an unclassified representative of Bacteroidota. Administration of the synbiotic significantly influenced cecal microbiota, with outcomes depending on the administration route but, importantly, varying significantly between food business operators and even trial repetitions. Overall, PoultryStar exerted limited effects on pathogen control and production performance, while external factors such as administration route and trial repetition strongly modulated outcomes. Our findings highlight the need for repeated, farm-level evaluations and tailored probiotic strategies to optimize broiler health. broiler synbiotic supplement Campylobacter jejuni Salmonella Infantis Cecal microbiota true false true Angleški jezik Angleški jezik Članek v reviji 2026-01-07 13:13:44 2026-01-07 13:13:51 2026-01-16 10:26:59 0000-00-00 00:00:00 2026 0 0 Str. 1-10 Vol. 105, [article no.] 106353 2026 0000-00-00 Zaloznikova Objavljeno apc 0000-00-00 0000-00-00 0000-00-00 636.09:616 1525-3171 10.1016/j.psj.2025.106353 263758595 Administration.pdf Administration.pdf 1 A1E868518F5E177269A0A5F1474CDA7C f2aa4c28c5dfc97d92a6a5fb6aac878ea1b82e483bf6b4b57169597bf2b6e349 84383c5e-ebc3-11f0-bf92-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=225105 https://www.sciencedirect.com/science/article/pii/S0032579125015937?via%3Dihub 1 53af781f-ebc2-11f0-bf92-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=225104 Veterinarska fakulteta 0 0 0