THE INFLUENCE OF FEEDING TYPES ON THE BIOPRODUCTIVE PERFORMANCE AND CARCASS FATTY ACIDS COMPOSITION IN THE CASE OF FATTEN SUCKLING LAMBS
D. Mierliţă, St. Daraban, F. Lup, Cristina Maerescu
The main objective of this study involves the influence of energy density and energy-protein ratio of feed ration on production, structure and content of Omega-3 polyunsaturated fatty acids and CLA in muscle tissue and adipose fat at suckling lambs under intensive fatting. Secondly, it was established influence of different systems of feeding on performance of lambs under intensive fatting, subjected to production and consumption, and on carcass and meat quality obtained. In accordance with the objectives an experiment of the 2 x 2 factorial type was organized, using mixtures of individual fodders with two different energy levels( high: 65% concentrated, and low: 35% concentrated) which did contain or not full structure soybean bypass (5% by weight). High energy density (from 1.00 up to 1.15 UNC/kg DM) and the incorporation of integrated soybean bypass type into food caused a radical improvement in weight gain and degree of recovery of feed, and have provided larger proportion polyunsaturated fatty acids (PUFA) in intramuscular fat. The differences are statistically assured. In comparison, PUFA had a higher weight in biceps femoris muscle than in longissimus dorsi muscle. The most significant differences were recorded in the polyunsaturated fatty acids Omega 3 series (C18: 3 n-3, EPA, C22: 3 n-3, DPA and DHA) and CLA C18:2 c9, t11, C18: 2 T10, C12). The largest amount of PUFA Omega 3 fatty acids was found in muscle tissue derived from lambs fed with the ration with the highest energy density and which contained the fully protected soybean. A similar evolution has recorded for the conjugated linoleic acid (CLA). If Omega-3 PUFA concentration did not show noticeable differences between the two examined muscle tissue (longissimus dorsi and biceps femoris), the proportion of CLA was found to be higher in biceps femoris muscle for all analysed lots. Compared with muscle tissue, fat depot (subcutaneous and perinea) is characterized by a higher content in saturated and unsaturated (particularly perirenal fat) and proportionally lower polyunsaturated fatty acids and especially Omega-3 PUFA series. The influence of energy density of food and the incorporation of full protected structure soybean ration had a similar influence on fatty acid profile of fat deposits, as much as in the case of intramuscular fat.
Key words: nutrition, energy, integral soybean bypass, Omega 3 and CLA, lambs