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: Towards the selection of chickens resistant to Salmonella and Campylobacter infections
Research conducted cooperatively with:
| Kaiser, Pete - |
| Howell, Joanna - |
| Fife, Mark - |
| Sadeyen, J - |
| Salmon, N - |
| Rothwell, Lisa - |
| Young, John - |
| Burt, Dave - |
Submitted to: Bulletin and Transactions of the Royal Academy of Medicine of Belgium
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 5, 2008
Publication Date: October 1, 2008
Citation: Kaiser, P., Howell, J., Fife, M., Sadeyen, J.R., Salmon, N., Rothwell, L., Young, J., Burt, D., Swaggerty, C.L., Kogut, M.H. 2008. Towards the selection of chickens resistant to Salmonella and Campylobacter infections. Bulletin and Transactions of the Royal Academy of Medicine of Belgium. 164:17-25.
Interpretive Summary: Baby chicks can get many diseases from bacteria such as Salmonella. We are trying to make chicks more resistant to these bacterial infections. The purpose of these experiments was to try to find changes on the genes of baby chicks that make them more susceptible to bacterial diseases. We have found many changes on the genes but are still trying to find those changes that are actually involved in giving protection to the baby chick. This work is very important to the chicken breeders because once we can identify these changes, we can then start breeding chicks that do not have these bad changes to make chicks that are less likely to get sick with bacterial diseases.
Resistance to infection with enteric pathogens such as Salmonella and Campylobacter can be at many levels and include both non-immune and immune mechanisms. Immune resistance mechanisms can be specific, at the level of the adaptive immune response, or non-specific, at the level of the innate immune response. While we can extrapolate to some degree in birds from what is known about immune responses to these pathogens in mammals, chickens are not “feathered mice,” and have a different repertoire of genes, molecules, cells, and organs involved in their immune response compared to mammals. Fundamental work on the chicken’s immune response to enteric pathogens is therefore still required. Our studies focus particularly on the innate immune response, as responses of heterophils (the avian neutrophil equivalent) from commercial birds and macrophages from inbred lines of chickens correlate with resistance or susceptibility to Salmonella infection with a variety of Salmonella serovars and infection models. We work on two basic resistance mechanisms – resistance to colonization with Salmonella or Campylobacter, and resistance to systemic salmonellosis (or fowl typhoid). To map genes involved in resistance to colonization with Salmonella and Campylobacter, we are using a combination of expression quantitative trait loci (eQTLs) from microarray studies allied with whole genome SNP arrays (WGA), a candidate gene approach and analysis of copy number variation across the genome. For resistance to systemic salmonellosis, we have refined the location of a novel resistance locus on Chromosome 5, designated SAL1, using high density SNP panels combined with advanced back-crossing of resistant and susceptible lines. Using a 6th-generation backcross mapping population, we have confirmed and refined the SAL1 locus to 8-00 kb of Chromosome 5. This region spans 14 genes, including two very striking functional candidates; CD27-binding protein (Siva) and the RAC-alpha serine/threonine protein kinase homologue, AKT1.