Supplemental Effect of Phospholipids and Requirement of Eicosapentaenoic Acid and Docosahexaenoic Acid of Juvenile Striped Jack

Abstract

A feeding experiment was conducted to determine the requirement for juvenile striped jack of eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA) and growth-enhancing effect of phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) when they were supplemented to defatted fish meal diets containing 0.05% n-3 highly unsaturated fatty acids (n-3HUFA). Fish fed a diet without supplemental essential fatty acids (EFA) showed low feed efficiency and high mortality was observed after 7 days of feeding (21 days from pre-feeding experiment), even though no external deficiency sign was visible. The cumulative mortality of this group was 48 after the 16th day. The results of this experiment on the EFA of juvenile striped jack can be concluded as follows: 1) DHA is more effective than EPA as EFA; 2) requirement for DHA alone is about 1.7% in diet; 3) EPA content in diet should be less than 0.8% to prevent ill effects; 4) the ratio 18: 1 to n-3HUFA in polar lipid fraction of whole body can be used as an EFA index for striped jack, a ratio less than 1 satisfying the EFA requirement; 5) Supplementation of 1.5 PC promoted good growth until about 3.3 g body weight, whereas PE was in-effective. © 1992, The Japanese Society of Fisheries Science. All rights reserved.