Influence of Dietary Lipid Sources on Growth and Fatty Acid Composition of Juvenile Abalone, Haliotis Discus Hannai Ino‪.‬

A study was conducted to evaluate the effects of dietary lipid sources on the growth and fatty acid composition of juvenile abalone Haliotis discus hannai Ino. Four triplicate groups of juvenile abalone (initial weight: 0.13 [+ or -] 0.04 g; initial shell length: 10.23 [+ or -] 1.48 mm) were led with one of four semipurified diets containing 3.5% of dietary lipid from either tripalmitin (TP), soybean oil (SO), linseed oil (LO), or 20:5n-3-enriched fish oil (FO), respectively, and were reared for 120 days in a recirculation water system. Results showed that the growth rate of abalone was significantly affected by dietary lipid sources (P 0.05). The dietary lipid, FO produced the highest weight gain rate (WGR, 413.2%), closely followed by LO (389.0%) and SO (382.4%). These three WGR values were not significantly different to each other. However, abalone fed the TP diet showed a significantly lower WGR (267.3%). Carcass moisture and protein were independent of dietary treatment, but the TP diet resulted in significantly lower carcass lipid. The fatty acid profile in abalone carcass reflected that of dietary lipids, especially the unsaturated fatty acids. It appears that H. discus hannai have a capacity to synthesize 20:5n-3, 20:4n-6 and 22:6n-3 from 18-carbon PUFAs and even from 16:0 through elongation and desaturation. However, the capacity seems to be insufficient to support the maximum growth of abalone. KEY WORDS: Haliotis discus hannai, lipid sources, fatty acid composition, growth, feeding and nutrition mollusk