Studies on Nutritional Myopathy Syndrome in Cultured Fishes-I

Abstract

In 1974, 1975 and 1976, nutritional myopathy occurred among cultured young puffers (Fugu rubripes) fed frozen fish meat, in a farm in Kagawa Pref. They were very thin and slender in appearance. One hundred and fifty three diseased puffers were examined histopathologically.This case was characterized by degeneration and necrosis of skeletal muscle fibers, proliferation of connective tissue and appearance of ceroid-laden macrophages in the stroma. It was found that such changes advanced more severely and quickly in erector and depressor muscle tissues than in lateral muscle tissues. In advanced cases most of the skeletal muscle fibers disappeared, and the connective tissue proliferated and ceroid-laden macrophages appeared markedly in the stroma.The lipopigment was deposited in parenchymal cells in the liver. This lipopigment was similar to ceroid in histochemical nature except that the pigment had no acid-fastness. Ceroid-laden macrophages appeared in the spleen, kidney and intestine.The present authors consider the above-mentioned changes closely resemble yellow-fat disease in mammals and aves.