A COMPARISON OF FATTY-ACID PROFILES AND CARCASS CHARACTERISTICS OF FEEDLOT STEERS FED CANOLA SEED AND SUNFLOWER SEED MEAL SUPPLEMENTS PROTECTED FROM METABOLISM IN THE RUMEN

The effect of feeding protected canola seed (PCS) and protected sunflo wer seed meal (PSM) supplements on the fatty acid profile and carcass characteristics of feedlot steers was examined. Fifty Hereford cross s teers, average weight of 290 kg, were assigned to five groups of 10 an d fed the following barley based concentrate rations for 133 days: I, control (containing 15% untreated sunflower seed meal (SSM)); II, PSM 15%; III, PCS 10%; IV, PSM 15% plus PCS 10%; V, PSM 15% plus PCS 15%. The inclusion of PCS, with and without PSM, increased the proportion o f C18 unsaturated fatty acids in the subcutaneous, perirenal and oment al fats; there were threefold increases in the proportion of linoleic (18:2) acid, fivefold increases in linolenic (18:3) acid and smaller i ncreases in the proportion of oleic acid (18: 1). There was a 20-25% r eduction in the proportion of palmitic acid, and the largest decrease was observed in the adipose tissue of steers receiving 15% PCS in the diet. Joint feeding of PCS and PSM significantly increased the dressin g percentage of carcasses in Groups IV and V and fat depth in Group IV .