Effect of Feed Withdrawal on Salmonella and SP6 Phage in Poultry Cecal in vitro Model
Salmonella is a principal food safety concern in the poultry industry, causing over 1.35 million cases of salmonellosis each year in the United States. While intervention strategies are employed to tackle this concern, the need for additional mitigation strategies is apparent. This study investigated the use of SP6 bacteriophage to reduce Salmonella in a poultry cecal in vitro model under both feed withdrawal (FW) and non-feed withdrawal (NFW) conditions. Cecal contents within each condition were pool anaerobic dilution solution and then administered the treatments as followed: cecal content only (control), Salmonella Typhimurium and cecal content, SP6 bacteriophage and cecal content, and finally Salmonella, SP6 bacteriophage, and cecal content. Samples prepared and sampled under anerobic conditions, with collections every 2 hours for 6 hours and saved for 16S rRNA sequencing. Sequencing occurred through the Illumina MiSeq platform and analyzed with Qiime2-2025.4. Overall, treatments groups (FW vs. NFW) exhibited significant differences in relative phylogenetic abundance at hour 4 and 6. Helicobacter and Ruminococcaceae were common taxa found in at least 80% of all samples at an abundance of at least 1%.The SP6 bacteriophage also showed a reduction in Salmonella in the FW group at hour 2. These results indicate that the microbial communities between FW and NFW differ from one another, which may impact the efficacy of the bacteriophage in a complex environment. Overall, this investigation demonstrates that bacteriophage may prove to be an effective mitigation strategy for Salmonella in poultry prior to entering the processing facility, which would be further supported through additional research.