Quantity and ratio of eicosapentaenoic acid/docosahexaenoic acid on growth and survival of black tiger prawn (Penaeus monodon) postlarvae

Abstract

The aim of this study is to determine quantity and ratio of eicosapentaenoic acid (EPA)/ docosahexaenoic acid (DHA) on growth and survival of black tiger prawn (Penaeus monodon) postlarvae. A completely randomized design experiment was used for this study. In this experiment, six diets contained two levels of % n-3 HUFAs (1.0, 1.5) and each level contained 3 EPA/DHA ratios (1:3, 1:2, 1:1). A control diet containing 0.35% n-3 HUFAs with the ratio EPA/DHA of 1:3 was used for comparison. Three replicates (100 postlarvae/m2) were used in each treatment. Postlarvae were fed 5 times/day. Results of 30 days feeding experiment showed an interaction between quantity n-3 HUFAs and ratio of EPA/DHA on growth and the osmotic resistance of postlarvae. The EPA/DHA ratio in the diet that improved growth of postlarvae was 1:1 at 1 % n-3 HUFAs and 1:2 at 1.5% n-3 HUFAs, respectively. On the contrary, the EPA/DHA ratio in diet 1:2 at 1% n-3 HUFAs and 1:3 at 1.5% n-3 HUFAs provided the high osmotic resistance of postlarvae. There were no effect of quantity and EPA/DHA ratio on survival of postlarvae. The dietary fatty acids have influence on the fatty acid composition in shrimp tissues. Polar lipids have more n-3 HUFAs than nonpolar lipids in the tissues of shrimp. And the ratio of EPA/DHA in diet also has an influence on the ratio of EPA/DHA in polar lipid more than nonpolar lipids. The suitable amount of n-3 HUFAs and the ratio of EPA/DHA recommended for normal growth and osmotic resistance of p. monodon postlarvae was 1.5 % and 1:2, respectively.