An official website of the United States government.
<OL><LI> Identify and characterize genes and their relationships to disease resistance in poultry with an emphasis on the major histocompatibility complex as well as other genes encoding alloantigens, communication molecules and their receptors and other candidate systems. <LI> Identify and characterize environmental, dietary and physiologic factors that modulate immune system development, optimal immune function and immune system related disease resistance and welfare in poultry genetic stocks.<LI> Develop, evaluate and characterize methodologies, reagents and genotypes to assess immune function and disease resistance to enhance production efficiency through genetic selection in poultry.
NON-TECHNICAL SUMMARY: Poultry products (eggs and meat) provide a major source of animal protein for human consumption; however, infectious disease reduces animal health and the efficiency of production, and can jeopardize food safety. To enhance the health of animals and to provide a permanent and environmentally friendly approach to host resistance to disease, methods must be found to genetically improve immune function and disease resistance in poultry. The purpose of this research is to characterize new relationships of genes with resistance to disease and to understand the relationship of the genetics of disease resistance and of production traits.
<P>APPROACH: Global transcriptional analysis profiles will be conducted on tissues or cells from chickens that demonstrate either high or low pathology after E. coli challenge, and both groups will also be contrasted with unchallenged birds. Comparative genomic analysis (chicken vs pig) will be conducted on transcriptional profiles of animals that are challenged with Salmonella to identify a set of avian-mammalian consensus genes that are differentially regulated with exposure of hosts to Salmonella. Dietary immunomodulators will be evaluated for their impact on expression of cytokines and other immune-related genes, under normal husbandry conditions and with immune-activating treatments (LPS injection or differing hygiene levels). The impact of dietary immunoenhancers on cellular response to Salmonella challenge will be assessed in vitro and in vivo. Primers for immune-related genes will be developed and their use for quantitative RT-PCR optimized. Correlations of immune-gene expression with parameters of growth and fitness will be assessed. The IA Station will maintain genetic lines of chickens for use in immune-related studies. Many of the IA long-term (10 to 100 generations) lines have been characterized for specific genes or features of immune responsiveness. These will include highly inbred lines in MHC-congenic pairs and trios, and advanced intercross lines for fine-mapping. Iowa has developed unique resource lines to identify candidate genes and QTL affecting response to Salmonella enteritidis. The pure founder lines of the resource population, and the advanced intercross lines, will be maintained and evaluated at the molecular level to locate genes and QTLs associated with bacterial burden and with vaccine response. Interval mapping and association analysis will be used. We will analyze the cellular mechanisms of defense by evaluating the in vitro phagocytic and killing capacity of isolated phagocytes, and will evaluate the profile of lymphocyte subpopulations in the peripheral blood by flow cytometry. We will also investigate gene expression variation associated with Salmonella response, by using microarrays. And, in cooperation with other stations, we will examine the proteome of birds that differ in response to Salmonella These populations remain valuable genetic resources for research conducted by collaborating NE-1016 members and other research institutions. The planning, cooperation and sharing of resources or expertise which takes place through participation in this project enhances discovery.