THE EFFECTS OF SEAWEED DIETS ON THE LIPID AND FATTY-ACIDS OF THE JAPANESE DISC ABALONE HALIOTIS-DISCUS HANNAI

The effects of seaweed diets on the lipid and fatty acid (FA) composit ion of juvenile abalone Haliotis discus hannai were investigated by fe eding seaweeds with different FA profiles: green (Ulva pertusa, rich i n 16:4n-3, 18:3n-3, and 18:4n-3 polyunsaturated fatty acids or PUFAs), red (Grateloupia sparsa, high in 20:4n-6 and 20:5n-3 PUFAs), and brow n (Undaria pinnatifida, rich in 18:3n-3, 18:4n-3, 20:4n-6, and 20:5n-3 PUFAs), in a 66-day feeding trial. The best growth was observed in ju veniles fed U. pinnatifida. None of the seaweed diets affected the maj or lipid classes of abalone tissues. The PUFAs, 16:4n-3, 20:5n-3, and 22:5n-3 were major FAs of abalone tissues even if these were undetecte d or found only in very small amounts in the seaweed diet, suggesting their synthesis from dietary n-3 series of lower fatty acids. The poor growth rates were associated with seaweed diets deficient in 18:2n-6, 18:3n-3, 18:4n-3, or 20:4n-6.