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An investigation of Salmonella spp. in Ontario nursery pigs and the impact of flavophospholipol on Salmonella and the porcine microbiota

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dc.contributor.advisor Friendship, Robert
dc.contributor.advisor Farzan, Vahab Nair, Saranya 2020-05-29T18:48:50Z 2020-05-29T18:48:50Z 2020-05 2020-05-22 2020-05-29
dc.description.abstract Salmonella spp. (Salmonella) in nursery pigs is challenging as it can promote the maintenance and circulation of the bacteria through all stages of pork production. Flavophospholipol, an antibiotic, may have the ability to reduce Salmonella in swine, as well as alter the gut microbiota in favour of beneficial bacteria by inhibiting pathogenic bacteria like Salmonella. Thus, the objectives of this thesis were: (i) to identify nursery barns with an active Salmonella infection and to determine the risk factors associated with an active Salmonella infection, and (ii) to evaluate the impact of flavophospholipol on Salmonella and the fecal microbiota of nursery pigs challenged with Salmonella Typhimurium. Serological and bacteriological methods were used to identify active Salmonella infections on Ontario nursery cohorts. Approximately 80% (37/46) of nurseries were found positive either using serological or bacteriological methods or both. Findings revealed that using both screening techniques in parallel, improved the sensitivity of identifying an active Salmonella infection on a nursery cohort. A logistic regression was used to assess risk factors associated with an active Salmonella infection in nursery cohorts. However, examination of risk factors didn't identify why the negative farms were different from the others, but this warrants further study. Second, an experimental study was conducted to assess the impact of in-feed flavophospholipol on Salmonella in weaned pigs challenged with Salmonella Typhimurium over 36 days. Using next-generation sequencing, the fecal porcine microbiota was studied in a subset of these weaned pigs receiving in-feed flavophospholipol compared to those receiving a non-medicated diet before and after challenge with S. Typhimurium. Medicating nursery diets with flavophospholipol at 4 ppm did not appear to reduce Salmonella infection (shedding, tissue, antibody response) in nursery pigs. With regards to the fecal porcine microbiota, results demonstrated a significant increase in phylum Proteobacteria (P=0.001) and decrease in Firmicutes (P=0.012) and genus Roseburia (P=0.003) in the treated pigs suggestive of possible microbial dysbiosis. In conclusion, based on these findings, it is difficult to conclude whether treatment with 4 ppm of flavophospholipol is aiding in reducing Salmonella and promoting favorable indigenous bacteria in the pig microbiota as previous literature has suggested. en_US
dc.description.sponsorship Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) – Food Safety Research Program, University of Guelph –OMAFRA Research Partnership, Swine Innovation Porc, Ontario Pork, Huvepharma, and Ontario Veterinary College provided funding for this research project. en_US
dc.language.iso en en_US
dc.rights Attribution-NonCommercial-NoDerivatives 4.0 International *
dc.rights.uri *
dc.subject Salmonella en_US
dc.subject flavophospholipol en_US
dc.subject swine en_US
dc.subject fecal microbiota en_US
dc.subject Ontario nursery pigs en_US
dc.title An investigation of Salmonella spp. in Ontario nursery pigs and the impact of flavophospholipol on Salmonella and the porcine microbiota en_US
dc.type Thesis en_US Population Medicine en_US Doctor of Philosophy en_US Department of Population Medicine en_US
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Attribution-NonCommercial-NoDerivatives 4.0 International Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivatives 4.0 International