EFFECT OF FLAXSEED OR SUNFLOWER OILS SUPPLEMENTATION ON NUTRIENTS UTILIZATION AND CONJUGATED LINOLEIC ACID (CLA) CONTENTS IN BARKI LAMBS MEAT

Abstract

The effect of adding flaxseed or sunflower oils to the diets of growing lambs on the performance, nutrient digestibilties, rumen fluid parameters, blood parameters, carcass characteristics and meat content from conjugated linoleic acid were investigated. Thirty six male Barki lambs, about 6 months old with average weight of 36 kg were used. Lambs were randomly divided into three groups, 12 lambs each. Each group was assigned to one of the experimental diets as follows: CON: concentrated feed mixture CFM (70%) + clover hay (30%) without oil (control), FSO: control +3% flaxseed oil and SFO : control + 3% sunflower oil. Oils were mixed with the diets daily immediately before feeding. The growth trial lasted for 16 weeks. Lambs were fed at 3.5 % DM of body weight levels. A digestion trial was carried out at the end of the feeding trial using six lambs per treatment. At the end of the trial, six animals from each group were slaughtered for carcass characteristics and determination of meat fatty acid profile. The results indicated that feeding growing Barki lambs on diets containing flaxseed or sunflower oils did not exert an additional effect on nutrient intake or any of the growth performance parameters. Oils supplementation had no significant effects on nutrient digestibilties. Ruminal pH, ammonia concentration and major volatile fatty acids (VFA) concentrations in the rumen were not affected by oils supplementation. Concentrations of conjugated linoleic acid (CLA) trans 10, cis 12 (t10, c12) and cis 9, trans 11 (c9, t11) in the rumen fluid increased with the tow oils. Addition of oils, significantly (p<0.05) increased the plasma concentrations of total cholesterol and triglycerides. The concentrations of hi density lipoprotein (HDL) were greater (p<0.05) in lambs fed with diets supplemented by oils than the diet without oils. Dietary oils supplemenatation had no effect on the carcass weight and dressing percentage. Meat of FSO group had significantly (p<0.05) higher content of poly unsaturated fatty acids (PUFA) compared to the other groups. Mono unsaturated fatty acids (MUFA) content in the meat of FSO group was significantly (p<0.05) higher than the SFO group. Saturated fatty acids (SFA) content were significantly (p<0.05) lower in the meat of animal fed on diet supplemented with FSO. The amount of CLA (c18:2 t10, c12) was significantly increased by about 86% and 83 % in meat of lambs fed FSO or SFO diets compared to the control group, respectively. The level of CLA (t10, c12) and Docosahexaenoic acid (DHA) were not found in liver fatty acids of lambs fed control diet, but they were formed in lambs fed diets supplemented with FSO or SFO. The FSO group had significantly (P<0.05) higher levels compared to the SFO group levels for c9, t11-CLA and DHA. From the results of the present study, it could be concluded that flaxseed or sunflower oils supplementation increased CLA and ω3 concentrations in Longissimus dorsi muscle and liver of lambs fed diets contained 3% vegetable oils. Key words: Flaxseed oil, sunflower oil, conjugated linoleic acid,performance, digestibility, rumen parameter, lambs.