Development of formulated diet for post-larval abalone, Haliotis diversicolor supertexta

This study examined the effects of formulated diets with/without emulsified fish oil on the survival and growth of post-larval Haliotis diversicolor supertexta. Agar was used as a binding agent and served as a carbohydrate source to make formulated diets. Post-larval abalone were settled on plastic plates and cultured in fiberglass reinforced plastics (FRP) tanks treated with 0.2 ppm ozone. Two experimental conditions, one with shading (90% light shading) and the other without shading were provided. The post-larval abalone were fed with (a) natural diatom biofilm (without diet supplementation, (b) formulated diet containing only agar, (c) formulated diet containing agar and Chlorella powder and (d) formulated diets containing 0.5, 1.0 or 2.0% emulsified fish oil and agar. Experimental duration was 35 days and survival, growth rate, daily growth rate, the amount of bacteria and attached diatoms were identified every 7 days. In the shading condition, post-larval abalone fed a formulated diet supplemented with 0.5% emulsified fish oil and a diet supplemented with Chlorella powder had a significantly higher daily growth rate than those fed other diets. Their daily growth rate in shell length was 78.5 μm/day and 77.5 μm/day, respectively. Post-larval abalone fed the diet with 0.5% emulsified fish oil had a significantly higher survival (35.1%) than those fed diets supplemented with only agar, Chlorella powder or natural diatom biofilm. For the treatment groups without shading, post-larval abalone fed a diet with 2% emulsified fish oil had significantly higher final size (3708 μm) and daily growth rate (98.8 μm /day shell length) than those fed diets supplemented with only agar or natural diatom biofilm.