A REVIEW OF MICRONUTRIENT REQUIREMENTS IN JUVENILE AND BROODSTOCK JAPANESE EEL, Anguilla japonica

Japanese eel, Anguilla japonica, is an important freshwater food fish cultured in East Asia. Farming of this species requires a nutritionally balanced diet to support its development. While the requirements for macronutrients have been established, the optimum levels for micronutrients of this species are still lacking. This review therefore summarizes the results obtained from a series of experiments conducted to evaluate the optimum requirements for micronutrients, including vitamin C and E, and arachidonic acid in juvenile and male broodstock Japanese eel (Anguilla japonica). On the basis of weight gain and feed efficiency, juvenile eels (initial body weight of 15 g) required Vitamin C and E supplementation between 41.1 and 43.9, and 21.2-21.6 mg/kg in the diets, respectively. Arachidonic acid levels at 69-71 mg/kg are essential for maximum growth rate of juvenile eel. For male Japanese eel broodstock (average body weight of 360 g), ascorbic acid (AA) concentrations in both liver and testis suggest optimum inclusion at 410.7-911.7 mg/kg in the diets. In addition, α-tocopherol should be supplied in the diets from 212.9 to 199.7 mg/kg. Requirement for arachidonic acid to achieve maximum weight gain of male eel broodstock is established at 71-92 inclusion levels.