Feedlot performance, carcass composition, and muscle and fat CLA concentrations of lambs fed diets supplemented with safflower seeds

Fifty wether lambs were used in a 48-day finishing study to evaluate the effects of feeding diets high in linoleic acid on animal performance, carcass characteristics and conjugated linoleic acid (CLA) content of muscle and fat tissue. Lambs were fed either a safflower supplemented diet containing 6% oil from safflower seeds or a control diet containing no added oil. Morlin safflower seeds, containing 37% oil with 79% linoleic acid, were utilized. Lambs fed the safflower supplemented diet had greater (P = 0.04)ADGthan those fed the control diet (0.29±0.01 kg per day versus 0.25±0.01 kg per day, respectively). Gain to feed ratio was greater (P = 0.02) for lambs fed the safflower than control diet (14.8 ± 0.54 kg/100 kg of feed versus 12.7±0.54 kg/100 kg of feed, respectively). Dressing percent, internal fat weight and longissimus muscle area did not differ (P > 0.30) between lambs fed safflower or control diets. However, back fat thickness tended to be greater (P = 0.17) for the lambs fed safflower diet (4.03 ± 0.48mm versus 3.03 ± 0.48 mm, for safflower versus control lambs, respectively). Fat content of muscle tissue was greater (P = 0.02) in safflower supplemented lambs (4.3 ± 0.23 g/100 g muscle tissue versus 3.4 ± 0.23 g/100 g muscle tissue for safflower versus control lambs, respectively). Safflower supplemented lambs had 2.3 percentage units lower (P = 0.004) oleic acid (C18:1), 2.6 percentage units higher (P < 0.001) linoleic acid (C18:2), and 0.25 percentage units lower (P < 0.001) linolenic acid (C18:3) in muscle tissue than did control lambs. Safflower supplemented lambs had two-fold increase (P < 0.001) in CLA concentration in muscle tissue (8969 ± 643 ppm versus 4050 ± 643 ppm for safflower versus control lambs, respectively) suggesting that the inclusion of high linoleic safflower seed in the finishing diets of lambs can have positive effects on fatty acid profile and especially CLA content in meat. © 2003 Elsevier Science B.V. All rights reserved.