Compositional and enzymatic characteristics of the Longissimus Dorsi muscle from large white, halothane-positive and halothane-negative pietrain, and hampshire pigs.

One-hundred-and-twenty-nine pigs from four genetic types-Large Whites, halothane-negative (HN) and halothane-positive (HP) Pietrains and Hampshires-were used to study some compositional and enzymatic muscle traits. Water, nitrogen, hydroxyproline and lipid contents, as well as lactate dehydrogenase and citrate synthase activities, were measured on all pigs, whereas glycogen phosphorylases (a and a + b), glycogen synthetase I + D and myosin isozyme pattern were determined on only fifty-six pigs. Hampshires were markedly different from the other genetic types with respect to the characteristics studied. Their Longissimus dorsi muscle contained less nitrogen (P < 0·0) and more lipid (P < 0·01) and presented higher hydroxyproline to nitrogen (P < 0·001) and water to nitrogen (P < 0·001) ratios, as well as noticeably higher citrate synthase (P < 0·01) and glycogen synthetase.