DIETARY PROTEIN REQUIREMENT OF JUVENILE ABALONE (Haliotis disucs Reeve, 1846)

Annual aquaculture production of abalone (Haliotis spp.) in Korea in 2000 was approximately 20 ton and reached 8,982 ton in 2014. This upward trend is expected to continue, given the high demand for abalone for human consumption. The optimum dietary protein and lipid requirements for abalone are reported to be approximately 25-35% and 3-7%, respectively. However, it may vary depending on abalone species. Since protein is one of the most expensive components in aquafeed, determination protein requirement is critical for abalone culture. However, no research on dietary protein requirement on juvenile abalone (H. discus Reeve), which is endemic to the waters off Japan and Eastern Asia, and secondly high aquaculture production after H. discus hannai in Korea has been performed yet. Therefore, dietary protein requirement of juvenile H. discus has been performed in this study.  

Five different levels crude protein of the experimental diets ranging from 20% to 40%, with an increment of 5% crude protein level at the expense of dextrin were prepared in triplicate (Table 1). Fish meal, soybean meal and casein, and dextrin were used as the protein and carbohydrate sources in the experimental diets, with fish and soybean oils as lipid source. One thousand and fifty juveniles, averaging 2.7 g, were randomly distributed into the 15, 70 L rectangular plastic containers (70 individuals per container), and 8 containers were randomly placed into each of two 9 ton concrete flow-through tanks with a flow rate of 48.2 L/min/tank. The abalone were fed the experimental diets once a day at 1700 h at a quantity to ensure satiation, with a small amount (about 2-3.5% of total biomass) remaining. The feeding trial lasted for 16 weeks.

Survival (83%>) of abalone did not significantly differ among the experimental diets. Dietary protein requirement was estimated to be approximately 32.96% based on growth rate (Fig. 1). Chemical composition of the soft body of abalone differed among the experimental diets.