三重大学水産学部, 現在, 日本レダリー株式会社, Faculty of Fisheries, Mie University, Miyazaki, Teruo, Ueno, Akitsugu, 宮崎, 照雄, 上野, 明次, 三重大学水産学部, 現在, 日本レダリー株式会社, Faculty of Fisheries, Mie University, Miyazaki, Teruo, Ueno, Akitsugu, 宮崎, 照雄, and 上野, 明次
In recent years,the practice of feeding chopped frozen fishes such as sardine,Japanese anchovy and chub mackerel to cultured yellowtail,Seriola quinqueradiata has been widespread among fish-culturists.This type of feeding, that is , frozen feed is reported to be effective for the weight gain of fed yellowtails and for the prevention of pollution of environmental water and outbreak of bacterial diseases (TANIGUCHI 1983).A question whether yellowtails undergo physiological disturbances when they eat frozen fish meat,has remained. In the present study, examinations were conducted feeding chopped frozen sardin(-4 to -2℃) to one group and miced thawed sardine (10 to 15℃) to another group of young yellowtails(190g of average body weight) for 20 days. At the end of the experiment, the weight gain was mostly the same in the fish fed the frozen feed and in those fed the thawed feed.Hematological data of red blood cell count, hemoglobin,hematocrit,serous total protein,serous albumin and serous cholesterol did not differ between the two fish groups. Data of serous glucose of fish fed the thawed feed were significantly high.Individual variations in hematological data of fish fed thawed feed were marked.Histopathological examinations indicated no obvious pathological change in the digestive tracts and other visceral organs of fish in either group.The results of this study indicate that yellowtails fed frozen feed will not undergo any phisiological disturbances.