Jeanne D. Joseph 1

A commercial crustacean diet (7% lipid) was impregnated with oil (3% by weight) extracted from heads of Penaeus setiferus and fed to juvenile Macrobrachium rosenbergii. After 3 weeks these prawns contained no more total lipid (1.4%) than control prawns fed the unaltered diet (1.3%), but changes in fatty acid composition were apparent. Whereas the sums of the saturates (25%), the monounsaturates (20%) and the polyunsaturates (54%) were the same for both groups, the experimental animals contained 6% more ω3 fatty acids and 6% less ω6 fatty acids than the control animals. Both groups contained the same percentage of ω3 fatty acids that were found in their respective diets, suggesting a retention of ω3 family acids. A more striking difference between the two groups was the far greater pigmentation in the experimental animals. Shrimp meals have been utilized in mariculture diets for a number of years, but these meals lack the pigmentation of fresh shrimp wastes because the carotenoids deteriorate when exposed to light, heat, and atmospheric oxygen. In contrast, oil extracted from the raw wastes is rich in carotenoids which are rapidly transmitted in the diet to laboratory reared prawns and result in a product more acceptable, visually, to the consumer.