Meat Science and Muscle Biology: How Does Pre- and Postnatal Muscle Development Affect Meat Composition, Quality and Value?

The cellular basis for postnatal muscle growth and hypertrophy has been realized over the past several decades. Skeletal muscle is extremely responsive to environmental and physiological cues by modifying growth and functional characteristics in accordance with the demands placed on it. This ability extends to instances of injury or trauma, where skeletal muscle exhibits the capacity to regenerate despite being largely composed of post-mitotic, multi-nucleated fibers. The plasticity of skeletal muscle results, in large part, from a population of resident stem-like cells, often referred to as satellite cells. When needed, satellite cells proceed through a terminal differentiation program culminating in fusion competency to participate in myogenic activities. The importance of satellite cell activity to skeletal muscle growth and hypertrophy is underscored when events leading to disruptions in myonuclear accumulation occur during critical growth or repair phases leading to muscle growth deficits that cannot be overcome. Although traditionally viewed exclusively in a myogenic role, new efforts have revealed novel roles, based on spatial, temporal and functional characteristics, ascribed to the satellite cell during muscle growth and repair. For example, the satellite cell location within the skeletal muscle niche and ability to produce numerous growth factors suggest communication between myogenic and angiogenic cell types exist. Recent experiments provide evidence that activated satellite cells initiate a potent pro-angiogenic program that may participate in vascularization of skeletal muscle. Coordination of myogenesis and angiogenesis may therefore be accomplished through the secretion of soluble factors by activated satellite cells.