Bacteriophage vB_SalS_KY05 controlsin poultry without disrupting cecal microbiota composition.

Abstract

Salmonellosis is a major food safety challenge in poultry production, requiring effective antibiotic alternatives. We isolated a polyvalent, vB_SalS_KY05, from a Taiwanese poultry farm and evaluated its biological properties andefficacy againstserovars Typhimurium and Enteritidis, and. The objective of this study was to comprehensively characterize vB_SalS_KY05 and assess its potential as a biocontrol agent for poultry farming. Genome analysis confirmed a lytic lifestyle with no detectable virulence or antimicrobial resistance genes. The phage remained stable at pH 4-10, at 41 °C, and in water for 7 days. For improved biosafety, large-scale amplification was achieved by switching the propagation host to non-pathogenicK12., SPF chickens challenged withTyphimurium received low-dose (10PFU/mL) or high-dose (10PFU/mL) phagedrinking water. Low-dose treatment reduced splenic, improved albumin-to-globulin ratios, and enriched beneficial taxa likeand. In contrast, high-dose treatment resulted in phage-bacteria coexistence and increased potentially harmful taxa including. Overall, cecal microbiota composition remained largely unchanged. These findings indicate vB_SalS_KY05 is a promising biocontrol candidate, highlighting the importance of dose optimization to enhance pathogen control while preserving gut microbiota stability in poultry production.