COMPARATIVE-STUDIES ON THE NUTRITION OF 2 SPECIES OF ABALONE, HALIOTIS-TUBERCULATA L, AND HALIOTIS-DISCUS-HANNAI INO .3. RESPONSE OF ABALONE TO VARIOUS LEVELS OF DIETARY-LIPID

This study was carried out to evaluate the effects of graded dietary l ipid levels on the survival, growth and body composition of Haliotis t uberculata and H. discus hannai. Six purified diets were formulated to provide approximately 25% protein, and a series of graded lipid level s, from 0.63 to 11.58%, in the form of a mixture of corn oil and menha den fish oil (1:1), The red alga, Palmaria palmata, was used as a cont rol diet. Abalone juveniles of similar size (H. tuberculata, 588 mg; H . discus hannai, 389 mg) were distributed in a recirculating system us ing a completely randomized design with 7 treatments and 3 replicates per treatment (20 juveniles/replicate), and fed the appropriate diet e very 3rd day for a 100-day period. P. palmata produced similar or bett er growth performance for both abalone species than the artificial die ts. Among the artificial diets, significantly higher weight gains were observed for H. discus hannai at dietary lipid levels ranging from 3. 11 to 7.09%, and for H. tuberculata at 3.11%. However, growth in terms of protein gain was best when both species of abalone were fed 3.11 a nd 5.15% dietary lipid, Soft-body lipid content positively correlated with dietary lipid levels. Inversely, soft-body protein concentrations decreased with the increase of dietary lipid. Overall, H. discus hann ai deposited a slightly higher level of lipid, but a lower level of pr otein than H. tuberculata. There were no significant differences in su rvival of abalone fed the experimental diets.