FIBRA MUSCULAR, DESEMPENHO E A QUALIDADE DA CARCAÇA DE QUATRO GRUPOS GENÉTICOS DE SUÍNOS

The objective of this study was to verify the performance and carcass quality of pigs from four genetic lines and to correlate these data with the number and diameter of muscle fibers. A total of48 pigs were used and distributed into four treatments: high-lean commercial crossbred line; prolificacy commercial crossbred line; (Landrace X Large White) crossbred animals; and undefined genetic line. The experimental design consisted of a complete randomized design with a 4 x 2 factorial arrangement (4 genetic lines and 2 genders). Daily weight gain, daily feed intake and the feed conversion were evaluated. At slaughtering, the carcasses were evaluated and the number and the diameter of the muscle fibers of longissimus dorsi were assessed. The high-lean commercial line presented the greatest number of muscle cells (P<0.05) while the Landrace x Large White crossbred line presented the greater diameter (P<0.05). High-lean commercial line showed a better performance and carcass characteristics compared with the undefined genetic line (P<0.05) and the barrows presented the lowest results (P<0.05). The increment in the muscle fiber number affected positively the performance and carcass characteristics of pigs. KEYWORDS: diameter of the muscle fibers; genetic groups; lean deposition; gender.