Meat Science and Muscle Biology Symposium: extracellular matrix in skeletal muscle development and meat quality.

For decades, research in muscle biology has been focused on enlarging skeletal muscle mass, which increases the quantity of meat production. It has been well established that myogenic cells are derived from multipotent mesenychmal stem cells (MSC). During the embryonic and fetal stages, muscle fibers are formed through the fusion of myogenic cells; enhancing the proliferation and myogenic differentiation of MSG increases the number of muscle fibers. After birth, muscle growth is characterized by enlargement of existing muscle fibers. Satellite cells, a pool of quiescent myogenic cells located underneath the basal lamina of muscle fibers, have an indispensable role in postnatal muscle growth. Recent studies have also identified MSG in adult muscle, such as perieytes, which are likely important to muscle growth. The MSG in muscle are most abundant during the early developmental stage and decrease as the maturity of muscle increases. In addition to the importance of the quantity of meat production, the quality of meat is becoming more and more important to consumers. There are 2 major quality problems facing the meat industry, especially the beef industry: marbling and tenderness. Marbling, or intramuscular fat, imparts fiavor and juiciness to the meat and is essential for the eating quality of meat. On the other hand, connective tissue and its crosslinking contribute to the background toughness of meat. Both marbling and connective tissue are located in the extracellular matrix of muscle fibers, with intramuscular adipocytes embedded in the connective tissue. Multipotent stem cells and satellite cells also exist in the extracellular matrix; the local extracellular environment.