Profile of fiber types in muscles from wild pigs native to the United States.

Histochemical and histological parameters of the longissimus (LD) and semitendinosus (dark and light portions) muscles from wild pigs native to Florida, USA, were investigated. All three fiber types were present in both muscles at varying proportions with typical (red fibers grouped in clumps and surrounded by white fibers) fiber arrangements for domestic porcine muscles (Cassens, 1971), contrary to the findings by Rahelic & Puac (1981), who examined the LD muscle of wild pigs native to Yugoslavia. These authors foud only βR fibers present in the LD muscle. In five of the six pigs in the present study, extremely and abnormally large fibers (giant fibers), possessing βR fiber characteristics, were observed. These giant fibers were found in both the LD and the semitendinosus (dark and light portions) and were not restricted to the periphery of the fasiculi. The presence of these giant fibers suggests some type of muscle myopathy syndrome in these pigs.