Indentification of Genes Involved in Antibody Response in the Chicken

NON-TECHNICAL SUMMARY: The economic well-being of animal agriculture depends in part on the development of novel strategies for producers to meet demands within increasingly global markets. Disease outbreaks have and will be major concerns in poultry production with serious consequences for the industry and the economy. Selection for disease resistance using biomarkers will provide a cost effective means to classical selection due to expense and difficulty in measuring these low to moderate heritability traits. The NC Avian Health Resource Population (AHRP) is an advanced intercross population consisting of reciprocal crosses of two lines of White Leghorns that have undergone long-term selection for high or low antibody response to sheep red blood cell (SRBC) antigen(s) and are also resistant or susceptible to M. avium, M. gallisepticum, E. coli, Eimeria (coccidiosis), Marek's disease, Newcastle disease, Staphylococcus, Feather mites, and avian influenza virus. This proposal has the following objectives: 1) Maintain and evaluate the NC-AHRP and collect phenotypes associated with specific diseases, and 2) Identify genetic markers associated with enhanced resistance to specific avian diseases. By challenging the resource population and subsequent genetic typing, gene(s) underlying the resistance to specific pathogens can be identified. Selection for resistance could provide a substantial barrier to the spread of disease in commercial birds and alleviate the potential threats to human health. The economic impact of this work is difficult to estimate but the threat of widespread disease could devastate the poultry industry in the U.S. causing significant loss of revenue, jobs, and communities involved in the poultry industry.<P>
APPROACH: The long-term goal of our research group is to develop strategies which enhance food animal production by promoting resistance. The overall objective of this application, which is the next step toward achieving our long-term goal, is to identify genes associated with enhanced resistance of poultry to disease. The central hypothesis of this application is that a genetic line of chickens selected for high antibody production to sheep red blood cells (HAS) exhibits differential resistance to disease than a genetic line of layer-type chickens selected for low antibody production to sheep red blood cells (LAS) due to genetic differences and variation in the sequence, structure, or resulation of specific genes. Our hypothesis has been formulated on the basis of strong preliminary data produced in our laboratory and from the scientific literature. The two genetic lines, HAS and LAS, have been reciprocally crossed to produce the North Carolina Avian Health Resource Population (NC-AHRP). Analysis of the antibody (Ab) and antiviral responses of the parent and progeny lines indicates a significant genetic component contributes to resistance to infectious disease. The rationale for the proposed research is that, once the gene(s) associated with resistance to a specific disease are identified, new and innovative breeding strategies can be developed to produce poultry with the ability to resist infection. This will be done by maintaining the advanced intercross generations of the NC-AHRP and challenging birds with different diseases, collecting phenotypes, and performing genetic analysis (SNP genotyping) to identify gene(s) underlying the response to specific pathogens.