The histochemical profiles of fibre types in porcine skeletal muscle

Using a variety of histochemical methods -mATPase staining after alkaline a nd acid preincubations, NADH-TR and alpha -MGPDH- we have investigated the fibre types in porcine skeletal muscle. The results reveal that four major fibre types -I, IIA, IIB and II*- can be separated histochemically in Longi ssimus lumborum muscle of Landrace pigs. The histochemical properties of th e muscle fibre type II* are very similar to that of type IIX described in o ther mammals. The existence of IIX fibres in pig muscle has been recently d emonstrated by molecular biology techniques and our results validate the us e of histochemistry (mATPase) as an easy methodology to differentiate the t hree fast myosins (type II fibres) in pig muscle.