Immune Response to a Salmonella Enteritidis Infection in Chickens Fed Different Immunomodulatory Nutrients

Abstract

Immunomodulatory nutrients alter the immune response to pathogens; modulating that individual's resistance to pathogen challenges. Salmonella enterica serovar Enteritidis (SE) causes mild illness in poultry, but causes over 1 million cases of human illness yearly, mostly due to contaminated eggs or undercooked meat. Pathogens undergo fast‐paced evolution creating problems for vaccination and antibiotic control; therefore it is important to investigate alternative avenues. The objective of this study was to characterize the immune response of juvenile chicks treated with known immunomodulatory nutrients: corn oil (control), fish oil, conjugated linoleic acid (CLA), and lutein, during a SE infection. Diets were isocaloric and isonitrogenous, with the basal diet consisting of soy‐bean meal, and rice. Four‐week‐old Hyline W‐36 chicks (n=96), were randomly allotted to 1 of 4 dietary treatments replicated in 6 pens of 4 birds per diet. All birds were orally dosed with 1 ml of 7.3 x 106 CFU/ ml SE in PBS after a 7 day diet adaptation. Liver, spleen, and duodenal (DMS) and ileal mucosal scrapings (IMS) were collected for immune related gene expression by rtPCR. The corn oil diet increased IL‐6 and iNOS expression across tissues. The fish oil and lutein diets increased IL‐1β, TLR‐4, and IL‐10 expression in DMS. The lutein diet decreased iNOS and TLR‐4 expression in the spleen. The lutein diet decreased SE presence in the DMS, but increased presence in the spleen where inflammatory cytokine expression was suppressed. The CLA diet decreased inflammatory cytokine expression across tissues, and SE presence was correspondingly increased in both the DMS and spleen. Thus, each dietary treatment altered the immune response to SE differently and this was reflected in the invasion of SE into tissues.