Chapter 3 - Myogenesis and Muscle Growth and Meat Quality

Abstract

The steps from determination of mesenchymal cells to myoblasts, proliferation of myoblasts, fusion of myoblasts into primitive muscle fibers, and maturation to highly differentiated muscle fibers are collectively termed myogenesis. The development of these steps is conserved across meat animals, including poultry. The outcome of myogenesis is the neonatal muscle fiber number, which positively influences subsequent performance traits. Myogenesis is sensitive to environmental treatments such as selection for performance, genotypes, intrauterine growth restriction (IUGR), and twinning. Furthermore, interventions against IUGR such as global nutrition, maternal protein level, maternal growth hormone treatment, and maternal supplementation with l-carnitine and l-arginine are possible in specific windows of opportunity. Besides muscle fiber number, postnatal muscle growth is dependent on muscle fiber type distribution and hypertrophy. The muscle fiber hypertrophy is related to two dynamic processes of muscle protein synthesis and degradation, supported by satellite cell proliferation, and affected by genotype, age, sex, and muscle type as well as nutritional strategies such as compensatory growth. The processes of muscle development and muscle growth are discussed in relation to meat quality traits.