Optimum levels of protein and lipid in purified test diet for the Japanese parrot fish [Oplegnathus fasciatus]

The Japanese parrot fish Oplegnathus fasciatus weighing 6.2g on average, were fed with diets containing different levels of protein (casein) and lipid (pollack liver oil) to determine the optimum levels of protein and lipid in the diet. After feeding for 40 days at 27°C in September-21°C in October, weight gain, feed conversion efficiency, protein efficiency ratio, body protein (or lipid) retention ratio and the contents of moisture, crude protein, crude lipid and crude ash in the fish bodies were examined. Based upon the results of these studies, the optimum protein (casein) level in the test diet for the Japanese parrot fish was estimated to be about 45% under the present experimental conditions. Also, the optimum lipid (pollack liver oil) level in the diet was about 8% when the dietary casein content was 50%.