饵料中不同脂肪水平诱导红姑鱼脂肪肝病的研究

1260尾初始重约为273g的红姑鱼(Sciaenopsocellatus)分为9组,每组3个平行,用9种不同水平蛋白质与脂肪日粮饲养于循环水系统的水泥池网箱内,在水温为232±20℃条件下养殖56d。本实验为饵料中不同脂肪水平诱导红姑鱼脂肪肝病的研究。9种日粮中蛋白质含量分别为:36%,40%,44%;脂肪含量分别为:4%,8%,12%。红姑鱼的各期生长率和存活率随着日粮脂肪含量增加而显著下降,红姑鱼肝胰脏脂肪含量与日粮脂肪水平成正比,各组红姑鱼均发生程度不同的营养性脂肪肝病,其病变程度与日粮脂肪水平成正相关。饲喂脂肪含量分别为8%,12%日粮的红姑鱼从实验3周起开始大量发病死亡,死亡率在5周达到高峰。主要表现为厌食,不游动,皮肤发黑,消瘦直至死亡。解剖见肝胰脏肿大,苍白发黄,柔软易碎。组织学检查发现,各组红姑鱼肝胰脏均见肝细胞不同程度的脂肪变性,溶解坏死,胰腺细胞亦萎缩。电子显微镜观察,在肝细胞线粒体、内质网与细胞浆内有大量微细至大颗粒状的脂滴出现。实验结果表明,饲喂9种不同水平的蛋白质和脂肪日粮的红姑鱼均引起营养性脂肪肝病,其病变程度与日粮脂肪水平成正相关,日粮中脂肪是红姑鱼发病与死亡的直接原因。  

STUDIES ON THE FATTY LIVER DISEASES RESULTED FROM DIFFERENT LIPID LEVELS IN SCIAENOPS OCELLATUS DIETS

An experiment was conducted to study of fatty liver disease resulted from difference lipid levels in juvenile Sciaenops ocellatus diets. 1260 Juvenile Sciaenops ocellatus (initial body weight ca. 2. 73g) were divided into 9 experimental triplicate groups and fed in aquatic cases by a recirculated filtered rearing systemmaintained for 8 weeks at 23. 22. 0. Nine kinds ofdiets were contained withdifferent protein levels (38%, 42%, 46%) and lipid levels (4%, 8%, 12%). The results showed that the relative growth ratio (RGR) and survival ratio (SR) in fish fed medium lipid diets (8%) or higher lipid diets (12%)were significantly lower than fish fed low lipid diets (4%) (P<0. 05), and the contents of lipid in hepatopancreas of fish were positive relatively with the lipid contents of diets. At end of the experimental period, fatty liver disease were found in fish by all nine experimental groups and a large of fishes fed medium lipid diets (8%) and high lipid diets(12%) occurred in serious il- lness and death from 3rd test week, then the top mortality was showed in 5th test week. The ill fishes were sick of eating and movie, black skin, thin and died at last. The main pathological change in ill fishes was fat liver disease. The hepatopancreas were swollen, pale, fatty degeneration and fatty necrosis of hepatocytes and pancreas atrophy. Ultrastural changes showed that there were a lot of fat granules in mitochondria, endoplasmicreticulum and cell plasm on hepatocyte. The research result indicated that all nine kinds of diets with different lipid or protein levels could cause nutritional fatty liver disease in juvenile Sciaenops ocellatus. The degree of pathological changes and serious level of fatty liver disease in test fishes had a close, positive relationship with the contents of the lipid in test diets, but not with the contents of protein in test diets. The raising level of lipid in test diets was sure to the direct cause of illness or death in juvenile Sciaenops ocellatus.