R. Slavov1*, G. Mihaylova1, St. Ribarski2, D. Panayotov1, D. Pamukova1, D. Dragnev1
1Department of Animal Science – Ruminants and Dairy Farming, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of Morphology, Physiology and Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 1 May 2016; accepted for publication 25 August 2016)
Abstract. A comparative analysis of amino acid composition of lamb meat from the North East Bulgarian fine fleece breed (I gr.) and its crossbreds from internal breeding with 25% heredity from the Australian merino (II gr.) and Ile de France (III gr.) breeds was conducted. Upon starting the experiment lambs were equal and during the experiment they were placed under similar conditions of feeding and rearing. To establish the amino acid composition of meat slaughter analyses were performed at 100 and 130 days of age. From the carcass of each slaughtered animal individual mean samples were taken. Studies were carried out in the Research Laboratory of the Faculty of Agriculture at Trakia University. As a result of the studies the following conclusions were made: 1⁄4 Ile de France crossbreds in a sophisticated crossing have the highest total amino acid content, including essential amino acids in the meat of 100- and 130-day-old lambs, 6.87% and 7.36%, respectively. The lysine/arginine ratio, relating to protein atherogenicity, varies within narrow ranges among groups and marks slight increase with age – from 1.31-1.37 at 100 days to 1.41-1.46 at 130 days. With the increase of age in crossbreds from internal breeding total protein amino acid content grows, that being most prominent in lambs from the III group – from 41.92 to 43.49%. The values of total protein indices increase compared to the reference protein (from 117.97% to 118.22% for II group and from 116.44% to 120.80% for III group) and the whole egg protein (from 89.39% to 91.92% for II group and from 90.53% to 93.93 for III group). It has been found that internal breeding of crossbreds with 25% heredity from the Ile de France breed has positive effect concerning the total amino acid content of lamb meat at 100 and 130 days of age, essential amino acid content in it and the levels of total amino acid indices. Internal breeding of crossbreds with 25% heredity from the Australian merino breed does not have an adverse effect on the levels of the studied traits.