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Yoon, Jong-Man
- Korean Journal of Ichthyology
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- v.12 no.2
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- pp.111-117
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- 2000
There were observed the histomorphological alterations such as chloride cell hyperplasia, branchial lamellar epithelial separation, the increased cellular turnover of chloride cells, glomerular shrinkage and blood congestion in rainbow trout (Oncorhynchus mykiss) during the seawater adaptation. The ultrastructure by scanning electron microscope (SEM) indicated that the gill secondary lamella of rainbow trout exposed to seawater, were characterized by rough convoluted surfaces during the adaptation. There were observed a large number of mitochondria with the elongate and well-developed cristae in chloride cells exposed to seawater by transmission electron microscope (TEM). The presence of two mitochondria- rich cell types is discussed with regard to their possible role in the hypoosmoregulatory changes which occur during seawater-adaptation. Glomerulus shrinkage and blood congestion were occurred higher in nephrons of seawater-adapted fish than those living in freshwater. Our findings demonstrated that rainbow trout tolerated moderately saline environment and the increased body weight living in seawater was relatively higher than that living in freshwater in spite of histopathological changes.
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CHUN Seh-Kyu;KIM Young一Gill
- Korean Journal of Fisheries and Aquatic Sciences
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- v.14 no.1
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- pp.37-42
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- 1981
Ichthyophonus disease broke out among rainbow trout (Salmon gairdneri) fry in November 1979, and after that a fish group containing diseased fish was kept for one year. The authors examined histopathologically the diseased fish 3 times, at 6 momths intervals. Diseased fish showed markedly stunted growth and darkish coloration, and anatomically the liver with small white nodules, the heart with red nodules, the spleen with granular nodules and the markedly tumefied kidney. Ichthyophonus invaded various tissues in the host and took the shape of multinucleate spherical or hyphal body. The multinucleate-spherical bodies contained many nuclei with a large nucleolus and granular cytoplasm. Histopathologically systemic dissemination and systemic proliferation by Ichthyophonus sp. wire indentified. In addition to a single multinucleate-spherical body appeared in the various tissue, large granulomas containing two to several generations of Ichthyophonus sp. were formed especially in the liver, kidey and spleen. The inflammatory response against Ichthyophonus was characterized by mononuclear-celluar proliferation with giant cell formation and fibrobasts proliferation.
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Kim, Wi-Sik;Kong, Kyoung-hui;Oh, Myung-Joo
- Korean Journal of Ichthyology
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- v.29 no.1
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- pp.75-79
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- 2017
About 10% mortality occurred in cultured rainbow trout Oncorhynchus mykiss at a marine farm in Jeju in 2014. Diseased fish showed markedly abdominal distension and distended stomach. Although parasites, bacteria or viruses were not isolated from diseased fish, numerous Candida sp. were isolated from distended stomach. In experimental infection with Candida sp., mortality was not observed in most fish and clinical sign of distended stomach was not observed in the fish. These results suggest that Candida sp. may not be the etiologic agent of stomach distension syndrome. This is the first report of stomach distension syndrome in seawater farmed rainbow trout in Korea.
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