MOLECULAR MECHANISMS REGULATING SKELETAL MUSCLE GROWTH AND DIFFERENTIATION

The identification of an optimal protein intake level (not a minimal requirement) for health and wellness has yet to be established for animals and humans. Much controversy exists concerning optimal protein nutrition for metabolic health and longevity. On one hand, increased intake of protein is associated with greater lean mass and mitochondrial function. On the other hand, lower protein intake is associated with reduced incidence of chronic disease and recent studies report that diets restricted in one or more essential amino acids reduces fat accumulation and promotes longevity while maintaining lean mass. The regulation of protein synthesis in muscle is key to regulating muscle mass. The eukaryotic translation initiation factors (eIF) and the intracellular signaling pathways associated with their expression and activity are critical regulators of anabolic growth in skeletal muscle. A deeper understanding of the mechanisms by which altered supply of dietary essential amino acids regulates muscle growth when in combination with a high fat diet and/or physical activity is necessary to devise optimal protein nutrition for animal growth and production. Results can be used to refine current diet formulations to maximize muscle mass in domestic animals and thus benefit the meat industry. To achieve this goal, rodent models (control wild type or genetically modified) will be fed diets containing different levels of essential amino acids in combination with different levels of dietary fat and/or physical activity. Body composition and fuel usage will be monitored in live animals and signaling pathways regulating protein synthesis will be assessed at the levels of mRNA and protein expression using standard biochemical and molecular biology approaches in tissues collected at the end of the study.