|Y Rodriguez, Torres|
Submitted to: Animal Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2010
Publication Date: 3/7/2011
Citation: Uthe, J.J., Bearson, S.M., Qu, L., Dekkers, J.C., Nettleton, D., Y Rodriguez, T., O'Connor, A., Mckean, J., Tuggle, C.K. 2011. Integrating comparative expression profiling data with association of SNPs to Salmonella shedding for improved food safety and porcine disease resistance. Animal Genetics. 42(5):521-534. Interpretive Summary: An alternative to antibiotic usage in food-producing animals is to select for animals with improved genetic resistance to zoonotic pathogens. To address this strategy, a search was conducted to identify genetic variations in pig genes that respond to Salmonella. Single nucleotide polymorphisms (SNPs) were identified in 31 pig genes whose expression is altered in response to Salmonella. To determine if the identified porcine SNPs were associated with tissue colonization or fecal shedding of Salmonella, three independent pig populations were genotyped for the SNP. Statistical analysis revealed 13 SNPs that associated with Salmonella fecal shedding or tissue colonization. These associations may be useful to industry, university and government researchers interested in improving food safety by identifying and selecting for pigs with increased resistance to Salmonella colonization
Technical Abstract: Salmonella in swine is a major food safety problem, as a majority of U.S. swine herds are Salmonella-positive. Salmonella can be shed from colonized swine and contaminate a) neighboring pigs; b) slaughter plants and pork products; c) edible crops when swine manure is used as a fertilizer; and d) water supplies if manure used as crop fertilizer runs off into streams and waterways. A potentially powerful method of addressing pre-harvest food safety at the farm level is through genetic improvement of disease resistance in animals. In this research, we describe a successful strategy for discovering genetic variation at candidate genes associated with disease resistance in pigs: integrating our recent global gene expression analysis of the porcine response to Salmonella with literature information on important candidate genes. We identified single nucleotide polymorphism (SNPs) in these functional candidate genes, and genotyped three independent pig populations with data on Salmonella fecal shedding or internal burden (total n=377) at these loci. Out of 31 SNPs genotyped, 21 SNPs segregated in at least two populations with a minor allele frequency of 15% or greater. Statistical analysis revealed thirteen SNPs associated with Salmonella fecal shedding or tissue colonization with an estimated proportion of false positives (PFP) = 0.2. The genes with associated SNPs included GNG3, NCF2, TAP1, VCL, AMT, CCR1, CD163, CCT7, EMP1 and ACP2. These associations provide new information on the mechanisms of porcine host response to Salmonella and may be useful in improving genetic resistance to this bacterium.