Optimum Level of Dietary n-3 Highly Unsaturated Fatty Acids for Juvenile Sea Cucumber, Apostichopus japonicus

A feeding trial was conducted to estimate the optimum level of dietary n-3 highly unsaturated fatty acids (HUFAs) for juvenile sea cucumber, Apostichopus japonicas, based on growth performance and fatty acid compositions. Diets with five n-3 HUFAs levels (0.15, 0.22, 0.33, 0.38, and 0.46%) were fed to sea cucumber juveniles (1.97 +/- 0.01g) once a day for 60d. The sea cucumbers fed diets containing 0.22% n-3 HUFAs showed significantly (P<0.05) higher body weight gain, feed efficiency, and protein efficiency ratio than the sea cucumbers fed diets containing 0.15% n-3 HUFAs, but not significantly different (P>0.05) from those of sea cucumbers fed diets containing 0.33, 0.38, and 0.46% n-3 HUFAs. The sea cucumbers fed diets containing 0.46% n-3 HUFAs showed significantly (P<0.05) higher eicosapentaenoic acid and saturated fatty acid than the sea cucumber fed diets containing 0.15% n-3 HUFAs, but not significantly different (P>0.05) from those of sea cucumbers fed diets containing 0.22, 0.33, and 0.38% n-3 HUFAs. The results of growth performance and n-3 HUFA compositions of body wall indicated that the optimum level of dietary n-3 HUFAs for juvenile sea cucumber is between 0.22 and 0.46%.