Study of the skeketal muscle fibers in purebred and crossbred Landrace, Large White and Duroc swine

The muscle fibers of the external obturador (1) and long of the neck (2) were analyzed in 12 swine, three from each genetic group. Histoenzymological techniques were employed ( HE – hematoxilin – eosin, acid mAtpase – Adenosin triphosfate miofibrilar, pH 4,6 and NADH-Nicotinamide Adenine Dinucleotide Tetrazolium Reductase). This allowed to classify them to metabolism type (anaerobic or aerobic) and muscular contraction type (slow or fast). It was concluied that muscle 1 possesses more than 50% of fast twitch glycolitic fibers and muscle 2 more than 40% of slow twitch oxidative fibers. Both presented larger percentage of fast contraction fibers. Regarding metabolism, muscle 1 has a glycolitic (anaerobic) while 2 has an oxidative (aerobic) character