Muscle morphology and the qualitative traits of the meat from crossbred ½ Dorper-Santa Ines lambs

Abstract

It were evaluated the effects of maternal feeding and finishing diets on the physical characteristics of carcasses, diameter and frequencies of muscle fibers SO (Slow Oxidative), FG (Fast Glycolytic) and FOG ( Fast Oxidative Glycolytic), the liveweight gain, shearing forces and weight losses under cooking of the M. semitendinosus and longissimus lumborum muscles of offsprings from eighty Santa Ines ewes which were mated with Dorper ram and fed with 8.80, 11.06, 12,27 and 15.03% of crude protein at the first third period of the pregnancy. The finishing diets were prepared with no sunflower grains (16.18% CP and 79.64% TDN) and with sunflower grains (15.03% CP and 78.96% TDN). The lambs were slaughtered at the liveweight of 32.31 ± 1.75kg. Postmortem samples were taken at the left side of half carcasses. There was no difference of the maternal feeding in the diameter of muscular fibers. The liveweight gain was positively correlated to the diameter of the three types of muscular fibers in the M. longissimus lumborum. The type of birth had influence in the loin eye area (simple = 12.37 and double = 11.26cm2). There were significant effects of the feedlot diet in the diameter of SO fibers in M. longissimus lumborum and in FG fibers in the M. semitendinosus. The M. longissimus lumborum presented higher tenderness than the M. semitendinosus under both finishing diets and type of birth. Shearing forces and losses by cooking indicate that the lambs could be finished with both diets.