Analyses of five gallinacin genes and the Salmonella enterica serovar Enteritidis response in poultry

Gallinacins in poultry are functional equivalents of mammalian beta-defensins, which constitute an integral component of the innate immune system. Salmonella enterica serovar Enteritidis is a gram-negative bacterium that negatively affects both human and animal health. To analyze the association of genetic variations of the gallinacin genes with the phenotypic response to S. enterica serovar Enteritidis, an F-1 population of chickens was created by crossing four outbred broiler sires to dams of two highly inbred lines. The F-1 chicks were evaluated for bacterial colonization after pathogenic S. enterica serovar Enteritidis inoculation and for circulating antibody levels after inoculation with S. enterica serovar Enteritidis bacterin vaccine. Five candidate genes were studied, including gallinacins 2, 3, 4, 5, and 7. Gene fragments were sequenced from the founder individuals of the resource population, and a mean of 13.2 single-nucleotide pollymorphisms (SNP) per kilobase was identified. One allele-defining SNP per gene was utilized to test for statistical associations of sire alleles with progeny response to S. enterica serovar Enteritidis. Among the five gallinacin genes evaluated, the Gal3 and Gal7 SNPs in broiler sires were found to be associated with antibody production after S. enterica serovar Enteritidis vaccination. Utilization of these SNPs as molecular markers for the response to S. enterica serovar Enteritidis may result in the enhancement of the immune response in poultry.