A candidate gene analysis for response to Salmonella enteritidis challenge or vaccination in young chicks

Abstract

Salmonella enteritidus (SE) contamination of poultry products is of global food-safety concern. The natural resistance-associated macrophage protein 1 (NRAMP1) affects host innate immunity to intracellular bacteria because of its ability to transport divalent cations in late endosome/lysosomes. Studying the association of the NRAMPl gene and chicken innate immune response to SE can, therefore, aid understanding and enhancement of chicken genetic resistance to SE. The chicken NRAMPl gene was investigated as a candidate gene for SE response in a unique resource population. Outbred broiler sires and three diverse, highly inbred dam lines (two major histocompatibility complex-congenic Leghorn and one Fayoumi line) produced Ft progeny that were evaluated as young chicks for either bacterial load in spleen and cecum after pathogenic SE inoculation, or antibody level after SE vaccination. Thirty-seven single nucleotide polymorphisms were identified in 3.1 kb of genomic DNA of the NRAMPl gene. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was developed to identify a single-nucleotide polymorphism (SNP) in a conserved transport motif. The sire NRAMPl gene SNP was significantly associated (P < 0.02) with antibody level to SE vaccine for Sire 8170 offspring in the two Leghorn crosses. In Sire 8296 offspring, NRAMPl was significantly associated (P < 0.02) with spleen bacterial load in the combined dam-line crosses. This study demonstrated the association of a SNP polymorphism in a highly conserved region of NRAMPl with SE vaccine and pathogen challenge response in young chicks. {