Studies on Nutritional Requirement of Fugu-III Effect of Dietary Dextrin, Feed Oil and Vitamins

Five test diets with 50% white fish meal, each of which contains different levels of dextrin, feed oil and vitamins were fed to fugu (Tahifugu rubripes) weighing 28.6g for 80 days in order to obtain basic information on development of a beneficial compound diet for culturing fugu. Growth and physiological conditions of the fish fed on the test diets were compared with those of the control group fed on sand lance (Ammodytes personatus). The growth of the fish fed on the test diets was slightly lower than that of the control group. Hepatic cells in the control and the test diet groups were distended by fatty globules. These globules in the test diet groups were smaller and more elliptic than the control group. However, PAS positive materials were highly accumulated in the hepatic tissue than that of the control group. No special abnormalities were observed in the lateral muscle and the digestive tract in both the control and the test diet groups. With the decrease in dextrin level in the diets, plasma and urine properties changed greatly and hepatosomatic index and hepatic cell diameter lowered. In the non dextrin group, dowdy swelling and vacuolar degeneration of epitherial cells of urinary tubules in the kidney were observed slightly. Optimum dextrin level was approximately 30%. Supplementation of 10% feed oil improved slightly growth, and hepatosomatic index and most properties of plasma and urine were nearly the same as those of the control group. But double dose of vitamins (6%) showed no effect on improvement in growth and physiological conditions. 受 領 日:昭 和63(1988)年6月16日 索 引 語:ト ラフグ/餌 料試験/配 合飼料 連 絡 先:〒724東 広 島市西条町下見 広 島大学生物生産学部 中川平介 Address : H. NAKAGAWA, Fac. Appl. Biol. Sci., Hiroshima Univ., Higashihiroshima 724