Are the n-3 fatty acids from dietary fish oil deposited in the triglyceride stores of adipose tissue?

Adipose tissue is the chief reservoir of the essential fatty acids (n-3 and n-6). To study the incorporation of the dietary n-3 fatty acids eicosapentaenoic acid (EPA) (20:5) and docosahexaenoic acid (DHA) (22:6), and a unique monounsaturated fatty acid, cetoleic acid (22:1n-11), into adipose tissue, rabbits were fed two different processed fish oils: MaxEPA (high in EPA and DHA; Seven Sea Ltd, Hull, UK) and herring oil (high in cetoleic acid). EPA and DHA increased from 0% of total adipose tissue fatty acid, in the adipose tissue of control rabbits to 2.2% and 4.9%, respectively, in MaxEPA-fed rabbits. The DHA-to-EPA ratio in the adipose tissue was higher than that in the diet, indicating alternative metabolic pathways for EPA. In the adipose tissue of herring-oil-fed rabbits, cetoleic acid increased from 0% to 7.9% of total fatty acids. The deposition of EPA and DHA was 1.8% and 2.8%, respectively. Our data indicated that these unique long-chain unsaturated fatty acids from dietary fish oils were readily incorporated into the fat stores from whence they could be mobilized.