Comparison of the contents of intramuscular amino acids in different lamb hybrids

摘要

Contents of amino acids in the musculus longissimus lumborum et thoracis were investigated in ramlambs, crossbreds between Merino ewes and rams of Oxford Down, Texel, Charollais, Suffolk and Merinolandschaf breeds. Lambs (n = 100) were slaughtered at the average age of 119.2 days. Average weight of lamb carcasses was 16.3 kg. Samples of muscles were collected 24 h after slaughter and they were analysed by oxidative acid hydrolysis of proteins with HCl (c = 6 mol/l). The alkaline hydrolysis of proteins with LiOH (c = 4.2 mol/l) was used for the detection of tryptophan content. The chromatographic analysis of a hydrolysate was performed using sodium citrate buffers and ninhydrin detection. The results were evaluated by the analysis of variance using the least squares method. The effects of slaughter date, slaughter age and live weight, litter size, sire breed and age and breed group of dam on amino acid contents were examined. A highly statistically significant (P < 0.001) effect of sire breed on the contents of almost all amino acids was found. The higher content of essential and semi-essential amino acids (EAA) compared to non-essential amino acids (NEAR) was detected in all examined hybrid combinations. Glutamic and aspartic acids were found as amino acids with the highest content among the NEAR. In the EAA group lysine, arginine and leucine showed the highest contents. The highest contents of leucine (6.70%), histidine (4.81 %), arginine (7.44%) and methionine (2.18%) were detected in the progeny of Texel sires. The progeny of Charollais rams showed the highest content of threonine (4.12%) and cysteine (0.92%), progeny of Merinolandschaf - valine (4.66%) and phenylalanine (4.56%), progeny of Oxford Down - lysine (8.33%) and progeny of Suffolk - isoleucine (4.32%) and tryptophan (1.10%). The highest total content of EAA was detected in the muscles of the progeny after Merinolandschaf sires (47.29%).