酸化油添加飼料によるハマチの飼育とビタミンE添加の効果

Abstract

In the previous papery1), the effect of antioxidant treated sand-eel as food for yellowtail was reported. Thereafter, we investigated the effects of oxidized oil and vitamin E administration on yellowtail fed with artifitial diets. Fish were fed for 93 days with diets containing 8.5% of fresh or oxidized cod liver oil to which DL-α-tocopheryl acetate was either added or not (Table 1). The weight gains of the fish are shown in Fig. 1 and Table 2. The fish fed with oxidized oil, without the addition of vithmin E, showed a slightly poor appetite after about 40 days of feeding, and at the termination of experiment a leaning of the dorsal muscle was observed on about 10% of the fish. These symptoms are probably due to muscle dystrophy as reported with the carp12) (Fig. 2). However such symptoms were not found in the vitamin E supplemented group. The muscle of fish fed with oxidized oil but without the addition of vitamin E showed a slightly higher TBA value than that of the vitamin E supplemented fish, but there was no extreme difference in the TBA values of the hepatopancreas of these two groups (Table 3). At the termination of experiment, the glycogen contents in the hepatopancreas of groups 1, 2, and 4 were elevated to about twice compared to its content at 70th day. However, such elevation of the glycogen level was not seen in the group fed with oxidized oil. The activities of transaminases (GOT, GPT) were higher in the fish fed with oxidized oil than the fish fed with fresh oil and these enzyme activities could not be reduced even by the administration of vitamin E. The alkaline phosphatase activity showed little, if any, difference between these groups (Table 4).