Single-Nucleotide Genomic Variation and Response to Salmonella Enteritidis in Chickens

NON-TECHNICAL SUMMARY: Infectious disease reduces animal health and production efficiency. Zoonotic pathogens, such as Salmonella, also endanger human health. This project will identify molecular genetic markers in chickens associated with beneficial host responses against Salmonella. Application will enhance animal health and food safety, and protect the multi-billion dollar U.S. poultry industry against bioterrorism. <P>

APPROACH: We hypothesize, and have provided the preliminary evidence to support, that multiple genes control the many innate and acquired immunological mechanisms that determine the persistence of Salmonella enteritidis (SE) in the host. Iowa has developed unique resource lines of chickens to identify genetic variation affecting response to SE. The pure founder lines of the resource population, and the advanced intercross lines, will be maintained and evaluated at the molecular level to locate genes and quantitative trait loci (QTLs) associated with bacterial burden and with vaccine response. Vaccine antibody response will be measured by enzyme-linked immunosorbant assay in blood samples taken at 3 weeks of age, after a commercial vaccination at 10 days of age. Bacterial burden will be measured by culturing tissues harvested from chicks after oral inoculation with pathogenic Salmonella. Genomic DNA will be analyzed for variation in single-nucleotide polymorphisms (SNPs) from the newly available international 2.8-million SNP map. First, the founder lines will be used to determine the informativeness of SNPs from the international map in the Iowa genetic lines. Then, informative SNPs of disease-related genes, and of SNPs evenly distributed across the genome, will by typed on birds of advanced intercross lines (F10 and later). Associations of SNP variation with the measured traits of SE response will be statistically tested. Interval mapping and association analysis will be used.