An Epidemiological Study of the Effect of Diet and Innate Immune Genotype on Salmonella Shedding and Colonization in Pigs

Abstract

The objectives of this study were to investigate Salmonella status in pigs from birth up to slaughter, and the effect of a low complexity nursery diet and genetic variants of the innate immune system on Salmonella shedding and colonization. On eight farms, 832 pigs were tested six times from birth to slaughter. Pigs received a high or low complexity (LC) nursery diet. A mixed-effect multilevel modelling method was used to analyze the data. Overall, 35% and 12% of pigs shed Salmonella once and more than once, respectively. Salmonella shedding increased with age (p = 0.01) and pigs fed the LC diet had a greater tendency to shed (p = 0.07). Salmonella shedding was not associated with colonization at slaughter. Variants in MBL1 and NOD1 were associated with increased Salmonella shedding (p < 0.01) and colonization (p = 0.02), respectively. This research may lead to future genetic and epidemiological research projects investigating methods to mitigate Salmonella on swine farms.