Study on vitamin E deficiency in amago salmon

In order to investigate the symptoms and histopathological changes of vitamin E deficiency in amago salmon, Oncorhynchus rhodurus, two purified diets with or without supplement of 400 mg vitamin E ( alpha -tocopherol) per kg of diet were administered to fish for 22 weeks in flowing-water aquaria. A recovery experiment was then performed, feeding the vitamin E deficient fish with a complete diet for the following 4 weeks. The fish showed lower appetite, reduced growth rate and mild anaemia. However, the survival rate was not significantly different from that of controls. The liver of most fish displayed focal atrophic hepatocytes with dilated sinusoids, multifocal necrosis perivasculis and also pericholangitis. In fish with these hepatic lesions, periarteritis was occasionally observed in the submucosa layer of intestine. These changes were clearly reversed at the end of recovery period. No sign of myopathy and ceroidosis was found.