Abstract
Current intensive pig meat production conditions impose the need to expand the knowledge about skeletal muscle characteristics, with the aim to improve both production of pig lean meat and meat quality. Histological and biochemical characteristics of the muscle highly infl uence the quality of meat, with muscle fi ber number, size and fi ber type distribution being important constituents. The objective of this study was to examine the structure of m. semitendinosus of piglets at birth, and slaughter pigs at the end of fattening. Total muscle fi ber number was 350 x 103 in newborn piglets and increased up to nearly 900 x 103 in slaughter pigs. At birth, the muscle consisted of 3.76% primary fi bers and 96.24% secondary fi bers. At slaughter, slow-twitch oxidative fi bers represented 21% of the total muscle fi ber number, fast-twitch oxidative fi bers represented 28 % while the majority of fi bers (52%) in m. semitendinosus were of fast twitch glycolitic type. Obtained results indicate that postnatal muscle growth is accomplished mainly by muscle fi ber hypertrophy.