Effect of feeding tuna oil supplement protected against hydrogenation in the rumen on growth and n-3 fatty acid content of lamb fat and muscle

To re-evaluate the incorporation of n-3 fatty acids into depot fats and mus cle a group of lambs were fed indoors a concentrate ration supplemented (3% DM) with much lower levels than used previously of rumen-protected tuna oi l for 42 days. A second group of lambs were fed diets supplemented with tal low (3% DM) to make the diets iso-caloric. There was no difference in final liveweight, average daily gain, hot carcass yield, or dry matter intake (D MI) between lambs fed with tallow and tuna oil-supplemented diets. Both eic osapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels in muscle ti ssue samples from tuna oil-fed lambs were thrice those in tallow-fed lambs (1.81% v. 0.61% for EPA; 1.51 v. 0.44% total fatty acids for DHA). There we re also significant incorporations of EPA and DHA into omental and perirena l fat. The level of linolenic acid in both muscle and adipose tissue of tun a oil fed lambs was double that of tallow-fed lambs. Feeding protected tuna oil significantly enhanced the n-3 fatty acid content of lamb meat.