Fatty acid composition of young Holstein bulls fed whole linseed and rumen-protected conjugated linoleic acid enriched diets

• Intramuscular fat had higher PUFA and n-3 and lower CLA than subcutaneous fat.
• Linseed supplementation increased n-3 and CLA fatty acids and decreased n-6/n-3.
• CLA addition achieved similar CLA levels to linseed supplementation.
• Linseed plus CLA showed additive effects in increasing PUFA and CLA in beef.

Forty-eight young Holstein bulls were used to evaluate the effect of whole linseed and conjugated linoleic acid (CLA) supplementation on beef fatty acid profile in intramuscular and subcutaneous fat. Animals were fed one of four isoenergetic and isoproteic diets: control (0% linseed, 0% CLA), linseed (10% linseed, 0% CLA), CLA (0% linseed, 2% CLA), and linseed plus CLA (10% linseed, 2% CLA). The fatty acid profile had similar trends in intramuscular and subcutaneous fat when diets were enriched with linseed and/or CLA, increasing the level of CLAc9,t11 and α-linolenic acid (ALA), and decreasing the n-6/n-3 fatty acid ratio. Supplementation with linseed improved the fatty acid profile by increasing the proportions of n-3 and CLA fatty acids and decreasing the n-6/n-3 ratio compared with the control. CLA addition achieved similar CLA tissue levels to linseed supplementation, but similar n-3 proportions to the control. Linseed plus CLA supplementation was more effective in increasing total polyunsaturated fatty acids and CLA compared with their individual addition. It is concluded that supplementation of whole linseed and/or CLA in bulls resulted in an increase in beef fat of some fatty acids considered to be of potential benefit to human health.