CLASSIFICATION OF BOVINE MUSCLE-FIBERS BY DIFFERENT HISTOCHEMICAL TECHNIQUES

The classification of bovine muscle fibres is of particular interest f or the food industry because meat tenderness depends in part on the pr oportion of the different types of fibres. It is, therefore, important to define reliable methods for classifying fibre types. There are sev eral classification systems. One is based on contractile type alone, a s revealed by myofibrillar ATPase activity or with antibodies against myosin heavy chain. Others take both contractile and metabolic types i nto account. In this study, the classifications of fibres obtained by these three systems were compared on the semitendinosus and longissimu s thoracis muscles of 35 Charolais bulls. Only the use of antibodies a llowed the identification of a proportion of hybrid fibres containing two isoforms of fast myosin heavy chain (2a and 2b). In addition, the combination of metabolic types showed that the metabolism of these hyb rid fibres differed according to the muscle. (C) 1998 Chapman & Hall.