THE GOAL OF THIS PROJECT IS TO ASSESS THE INVOLVEMENT OF SKELETAL MUSCLE STEM CELLS CALLED SATELLITE CELLS AND THEIR FUNCTION IN A COSTLY MYOPATHY WHICH MANIFESTS IN THE FASTEST-GROWING, HEAVIEST-MUSCLED BROILER CHICKENS CURRENTLY PLAGUING THE GLOBAL COMMERCIAL POULTRY INDUSTRY CALLED "WOODEN OR WOODY BREAST" (WB). THIS DEGENERATIVE MYOPATHY IS CHARACTERIZED BY EXTENSIVE COLLAGEN ACCUMULATION (FIBROSIS) WITHIN BREAST MUSCLE RESULTING IN MEAT THAT IS HARD TO THE TOUCH, HAS REDUCED CONSUMER ACCEPTABILITY, AND LOW VALUE DUE TO POOR PRODUCT FUNCTIONALITY, WHICH ULTIMATELY COSTS THE US BROILER INDUSTRY HUNDREDS OF MILLIONS OF DOLLARS ANNUALLY. OUR PRELIMINARY DATA SHOW THAT THE MUSCLE SATELLITE CELL POPULATIONS, WHICH ARE ESSENTIAL FOR MUSCLE GROWTH, ARE SIGNIFICANTLY ALTERED IN WB-AFFECTED BIRDS. WE PROPOSE TO USE A COMBINATION OF EXPERIMENTAL APPROACHES TO INVESTIGATE THE FUNCTIONALITY OF THESE ESSENTIAL STEM CELLS IN WB-AFFECTED BROILER CHICKENS. THE PROJECT OBJECTIVES ARE TO: 1) ASSESS THE EXTENT TO WHICH SATELLITE CELL FUNCTION IS IMPAIRED IN WB-AFFECTED BIRDS, 2) DETERMINE WHETHER THE APPARENT ABERRANT FUNCTION OF THE SATELLITE CELL POPULATIONS ARE DUE TO AN ISSUE WITH THE SC THEMSELVES AND/OR THEIR ENVIRONMENT USING A COMBINATION OF CELL ISOLATION, LABELING, TRANSPLANT, AND TRACKING STRATEGIES. SUCCESSFUL ACHIEVEMENT OF OUR PROJECT WILL NOT ONLY PUSH US TOWARD ELIMINATING THIS FOOD QUALITY PROBLEM, BUT SIMULTANEOUSLY INCREASE OUR KNOWLEDGE OF BASIC SKELETAL MUSCLE GROWTH MECHANISMS WHICH WILL FURTHER ENHANCE OUR ABILITY TO PRODUCE ENOUGH HIGH QUALITY, NUTRITIOUS CHICKEN MEAT PRODUCTS TO MEET CONSUMER DEMAND.