Recent advances in research on bovine muscle and meat sensory quality. I. Towards a better knowledge of muscle biology.

摘要

In the past, the major objective of research on meat-producing ruminants was to increase meat production with low costs of production. Nowadays, the meat safety crisis and the unreliability of meat eating quality have increased the concern of consumers for natural feeding of the animals, human health and high quality beef. Quality is thus one of the most important social and economic challenges for beef producers and retailers. Beef quality traits (tenderness and flavour) depend on various muscle characteristics which are regulated by genetic and breeding factors. However, the muscle traits studied so far (fibre number and characteristics, collagen characteristics and intramuscular fat content) explain only a moderate part of the variability in tenderness and flavour. Furthermore, predictive equations of tenderness and flavour from muscle characteristics depend on muscle types and animal genotypes. The development of new molecular techniques (functional genomics) has opened the way to an almost exhaustive analysis of gene expression in various nutritional and physiological conditions. This allows scientists to discover new biological predictors (i.e. new highly regulated genes) that control meat quality traits. Growth in utero plays a major role in the determination of muscle fibre number and characteristics, thereby regulating muscle growth and meat quality traits in postnatal life. Thus, the chronology of myogenesis is the subject of active investigation. Muscle contents in type I and III collagens are the highest at 180 days post-conception and decrease thereafter. Three generations of myoblasts have been described in bovine muscle during fetal life. On the basis of its muscle characteristics, the bovine is a mature species at birth compared to other mammals. Fetal muscle differentiation depends on genetic and nutritional factors. For instance, undernutrition during fetal life impedes muscle differentiation and changes metabolism in a way that may be detrimental for postnatal growth. In conclusion, growth in utero highly regulates some muscle characteristics (fibre, collagen and fat) which are important for beef quality. Therefore, fetal growth is likely to play a major role in the ability of cattle to produce beef of high and consistent quality..