Association of Micrometric Traits on Meat Quality, Fattening and Slaughter Traits in the Pig

Investigations on histochemical activity of succinate dehydrogenase (SDH), meat quality, fattening and slaughter traits of M. longissimus were carried out on 94 White Zlotnicka pigs. Fibers from five randomly selected metabolic bundles were classified into βR (slow-twitch, oxidative), αW (fast-twitch, glycolytic) and αR (fast-twitch, oxidative and glycolytic) types, counted and their diameter was measured. Average diameter of fibers for the whole population was 60.1 μm, and their average number in the bundle was 33.8. Among the three metabolic types of fibers, 20.6% were classified as βR, 66.3% as aW type and 12.6% as αR type. Differences (P<.05 and P<.01) in micrometric traits between the progeny of particular boars were found in the number of βR, αR and aW fibers and in the average number of fibers in a bundle. These results can be utilized in breeding plans for the control of both growing traits and meat quality. Negative correlations were found between age on slaughter day and percent of βR fibers (−.2515, P<.05), density of ham and number of βR fibers (−.2146, P<.05), meat pH, and number of aR fibers (−.3559, P<.01), and meat pH1 and percent of αR fibers (−.4413, P<.01). Positive correlations were found between meat pH1 and number of βR fibers (.2326, P<.05) and between meat pH1 and percent of βR fibers (.4861, P<.01). Also, dressing percentage was positively correlated with number of αR fibers (.2112, P<.05), diameter of αW fibers (.2108, P<.05) and average diameter of fibers (.2116, P<.05). Significant, although low values of correlation coefficients between investigated traits do provide evidence for their consideration in breeding programs.