Chicken heterophils from commercially selected and non-selected genetic lines express cytokines differently after in vitro exposure to Salmonella enteritidis

Resistance to pathogens such as Salmonella enteritidis (SE) is a heritable trait important in maintaining the health of chickens and reducing bacterial contamination of poultry products. In chickens, heterophils act as the first responders to bacterial infections and are, therefore, responsible for initiating the immune response against SE challenge. This study measured mRNA expression of several immune response genes [interleukin-6 (IL-6), IL-10, transforming growth factor-β4 (TGF-β4), granulocyte macrophage-colony stimulating factor (GM-CSF), and Toll-like receptor-4 (TLR-4)] by heterophils from broiler, Leghorn, and Fayoumi chickens, either non-stimulated or stimulated in vitro with SE using quantitative reverse-transcriptase PCR. We found that heterophils of commercially selected broiler and Leghorn birds had differing early heterophil responses to SE in comparison with the native Fayoumi line. Heterophil stimulation with SE in vitro increased expression of pro- (IL-6 and GM-CSF) and anti-inflammatory cytokine mRNA (IL-10 and TGF-β4) in the Fayoumi line, while the broiler and Leghorn line heterophils had decreased or no changes in the cytokine gene expression levels. The unique response of the Fayoumi line is in contrast to the lines with a history of genetic selection to increase growth or reproduction, a process which may favor reduced or suppressed inflammatory responses. The findings illustrate the potential value of native lines to provide biodiversity to enhance innate health in commercially selected poultry.