FUNCTIONAL GENOMICS AND GENETIC ANALYSIS OF THE INNATE IMMUNE RESPONSE REQUIRED TO RESIST FOOD-BORNE BACTERIAL INFECTIONS IN POULTRY
Location: Food and Feed Safety Research
Title: In ovo treatment with CpG oligodeoxynucleotides decreases colonization of Salmonella enteriditis
Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 2, 2008
Publication Date: February 15, 2009
Citation: MacKinnon, K.M., He, H., Swaggerty, C.L., McReynolds, J.L., Genovese, K.J., Duke, S.E., Nerren, J.R., Kogut, M.H. 2009. In ovo treatment with CpG oligodeoxynucleotides decreases colonization of Salmonella enteriditis. Veterinary Immunology and Immunopathology. 127:371-375.
Interpretive Summary: Induction of the innate immune response in newly hatched chickens is important for limiting infections with bacteria, such as Salmonella enterica serovar Enteriditis (SE). CpG oligodeoxynucleotides (CpG-ODN) can stimulate the innate immune response of young chickens. Therefore, we examined the effectiveness of CpG-ODN administered in ovo on reduction of SE infection in young chickens. Heterophils were isolated from 2-day-old chickens treated with PBS or CpG-ODN and were stimulated with heat-killed SE or PMA for oxidative burst and heat-killed SE or live SE for degranulation assays. CpG-ODN treatment had no effect on heterophil oxidative burst when stimulated with heat-killed SE or PMA. However, HK-SE and live SE increased degranulation (P less than 0.01) in heterophils from CpG-ODN-treated animals compared to PBS-treated controls. In ovo treated birds were orally infected with SE on day 10 post-hatch and cecal contents were collected 6 d later for assessment of SE colonization. CpG-ODN treatment decreased colonization by greater than 10-fold (P less than 0.001) compared to PBS-injected control birds. Overall, our results indicate CpG-ODN given in ovo stimulates innate immune responsiveness of chicken heterophils, and we show for the first time that in ovo CpG-ODN treatment increases resistance to SE.
Baby chickens can become infected with disease-causing bacteria, such as Salmonella, soon after hatching. If these bacteria are still present when the chicken is processed for consumption, then they can cause humans to become sick. Immune cells in baby chickens can recognize the bacteria with proteins called toll-like receptors that bind to bacteria. One of the things produced by the bacteria that can bind to one of the toll-like receptors and activates the immune system of the chickens, certain DNA sequences, can be synthetically made. We put this DNA in eggs before the chickens hatched, a common practice in the poultry industry. The DNA makes the immune response of the chicken stronger, and we showed it decreases the amount of bacteria in the chickens after they hatched This information is important because decreasing the amount of bacteria in the chickens can make them healthier, and it also decreases the chance that humans will get sick from consuming poultry.