• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.24-29
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• 1998

Effect of extracellular calcium in vitellogenin (VTG) production in response to estradiol-17 $\beta$ $(E_2,\;2\times10^{-6}M)$ was examined in primary hepatocyte culture of rainbow trout, Onchorhynchus mykiss. Total calcium in estrogenized sera significantly increased, compared with the control, while diffusible calcium was insignificant. However, diffusible calcium in the incubation medium with $E_2$ was significantly reduced, compared with the control. The uptake of extracellular calcium by cultured hepatocytes signifIcantly increased 90 min after $E_2$ addition. Moreover, the accumulation of intracellular calcium increased in the cultures with $E_2$, regardless of the calcium concentrations in the incubation media. In addition, $E_2-primed $ VTG production was significantly decreased by withdrawal of E_2$ from the incubation medium. Moreover, VTG production by $E_2-primed$ hepatocytes was reduced by removing calcium from the incubation medium with or without $E_2$. These results suggest that the entry of extracellular calcium into the cytoplasm is an important step for VTG production in primary hepatocyte cultures in rainbow trout.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.928-931
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• 1996

The present study was carried out to compare the difference of proximate composition and lipid peroxides in juvenile(80~120g) and adult(670~690g) rainbow trout(Oncorhynchus mykiss). There was a marked increase in lipid content with growth. The fatty acids of juvenile rainbow trout was composed of saturates, monoenes and polyenes of 30.18%, 37.81% and 25.09%, respectively. Adult rainbowtrout showed higher content in monoenes and lower content in polyenes. The composition of amino acid was similar. In both groups, glutamic acid, aspaitic acid, histidine were abundant. The lipid peroxides, malondialdehydes and lipofuscin, were not increased significantly with growth.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.3
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• pp.231-242
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• 1990

A study is reported which investigated the additive nature of digestible energy (DE) from dietary nutrients and to estimate the relative energy values of different energy-yielding nutrients in practical trout diets. A growth study was conducted over 12 weeks with 6 diets. Rainbow trout (Oncorhynchus mykiss) were fed diets once a day ad libitum. Digestible energy values determined and calculated had direct relationship indicating additive nature of such values for feed ingredients. Overall growth performance was best in a diet containing 33% digestible protein (DP) with a DP/DE ratio of 18.6. A reduction in digestible protein level with the same DP/DE rat io led to a significant decrease in growth and feed efficiency. The increase of 7% of lipid with concomitant decrease in protein resulted in the relative gain of 130% in growth and nutrient retention, suggesting that 1 g of lipid is equal to about 1.3 g of proteins in terms of net energetic value. Replacement of 10% of dietary lipid by carbohydrates led to a slight decrease in energy retention efficiency but to a great increase in lipid retention efficiency (130%) showing that dietary carbohydrates led to increased lipogenesis.

• Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.135-142
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• 2000

In order to clarify the role of gonadal sex steroids in the synthesis of gonadotropin (GTH) subunits in immature rainbow trout, we examined in vitro and in vivo effects of testosterone (T) on the pituitary mRNA levels of GTH I $\beta$, GTH II$\beta$ and a subunits by Northern blot analysis and on the pituitary content levels of GTH I$\beta$ and GTH II$\beta$by radioimmunoassay (RIA). The mRNA levels of the a subunit in T-treated fish were not changed more dramatically than those in control fish both in vivo and in vitro. Interestingly, the mRNA levels of GTH I$\beta$ in T-treated fish were shown to be slightly lower than those in the control fish under these experimental conditions, but no differences were observed in pituitary GTH I$\beta$ contents. In contrast, the mRNA levels and pituitary contents of GTH II$\beta$ subunit were strongly increased by T both in vivo and in vitro. These results demonstrate that the expressions of GTH I$\beta$ and II$\beta$ subunit genes in immatue rainbow trout pituitary are subjected to differential regulation by T.

• Journal of Microbiology
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• v.38 no.1
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• pp.1-7
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• 2000

Eight strains of Aeromonas hydrophila isolated from diseased trout in Korea were characterized and compared with an American type strain by various methods including biochemical and physiological tests, PCR, randomly amplified polymorphic DNA (RAPD), plasmid profiling, and gel electrophoresis of total, membrane, and extracellular proteins. Virulence factors such as surface array proteins, cytotoxin, hemolysin, haemagglutinin, and protease were also investigated. The Korean strains showed heterogeneity in Iysine decarboxylase production, utilization of various carbon sources, and production of acetoin. Five strains had the same profiles of total and membrane proteins. Six strains haemagglutinated with trout red blood cells (RBCs) which was inhibited by fucose, galactose, and mannose, except for No. 1 where haemagglutination was inhibited by only galactose and mannose, but not by fucose. Four isolates haemagglutinated with human RBCs which was inhibited by fucose and mannose yet not by galactose. The type strain haemagglutinated only with trout RBCs which was inhibited by fucose, galactose, and mannose. Every isolate secreted protease, hemolysin, cytotoxin, and siderophore, but no enterotoxin. Results showed that the Korean isolates, except for No.7, had very different biochemical and molecular characteristics from those of the American type strain.

• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.125-132
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• 2008

The development of a fish that functionally provides both antioxidant and fat-reducing effects is an important goal in nutrition and aquaculture research. Dietary conjugated linoleic acid(CLA) can be successfully incorporated in fish muscle and viscera, but CLA and carotenoids have not been evaluated in such fish. An 8 weeks growth trial was conducted using rainbow trout, and all fish were fed twice daily with experimental diets containing graded amounts of CLA(1% and 5%). At the end of the experiment, the daily growth index, feed conversion rate, lipid class, and fatty acid composition were determined. Dietary CLA did not enhance the growth parameters of rainbow trout but did improve the feed conversion rate. The muscular polar lipid content decreased during the feeding period, while the content was stable in the viscera. In addition, a diet high in CLA decreased the polyunsaturated fatty acid content, but had no effect on the content of monounsaturated and saturated fatty acid in muscle.

• Journal of fish pathology
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• v.16 no.2
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• pp.81-90
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• 2003

High mortality with signs similar to viral haemorrhagic septicemia (VHS) such as severe haemorrhages in the skin, muscle and air bladder occurred in the farmed adult rainbow trout, Oncorhynchus mykiss, in Ku-mi and Je-chun area in Korea. The isolates were neutralized by an antiserum against IHNV but not by antisera against VHSV. Electron micrograph of an ultrathin section showed large numbers of bullet-shaped virus particles. The newly isolated rhabdovirus was composed of five structural proteins. In the western blot analysis Ihe anti-DiNV serum strongly reacted with G. N and MI protein. The cumulative mortalities of RTK infected rainbow trout (10-12cm.9-12g) with $10^{3.5}\;and\;10^{1.5}TCID_{50}/m{\ell}$ were 80% and 30%. respectiveIy_ RTJ infected fish showed 50% mortality by infection with $10^{3.5}TCID_{50}/m{\ell}$. Control group and IHNVChAb exhibited no mortality. From these results, the viruses were identified lHNV although diseased fish showed similar sign. with VHS and caused high mortality in large-sized fish.

• Journal of Microbiology
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• v.34 no.2
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• pp.124-130
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• 1996

A survey was conducted to determine the prevalance of infectious pancreatic necrosis virus (IPNV) on fish farms in Korea and the epidemiology of IPNV infection in the farmed rainbow trout. In total, 43 pools of rainbow trout with apparent signs of viral infection from five provinces were obtained and analyzed. Evident cytopathic effects, including karyopycnosis and cell destruction, were observed in CHSE (chinook samlmon embyro)-214 cells infected with the virus isolates. Of these, ten viral isolates were assumed to be IPNV based on biophysical properties. RNA analysis revealed that the isolates contained two-segmented RNA genomes, further indicating that the viral isolates are IPNV. Antigenic comparison of the IPNV isolates identified three distinct serological groups separable by the cross-neutralization test. Of the ten IPNV isolates, six could be classified as strain DRT, two as strain Ab, and two as strain VR299. We were not able to isolate new strain of IPNV or any isolate serologically similar to the standard strain Sp.poraceae and families of the Agaricales, they are genetically more related to the Polyporaceae. These results are consistent with morphological characters observed in those mushrooms. However, it is premature to conclude taxonomic status Ganoderma species in the present study employing small sample size.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.450-455
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• 1996

The genomic DNA was prepared from trout liver which was treated with 3-methycholanthrene, and cloned into lambda EMBL3 at BamHl site. The genomic library was constructed via infections of these recombinant phages into E. coli K802, and screened by the most $5^I$-portion of trout CYP1A1 cDNA. After the screening of $10^9$ clones of the amplified library, 12 positive clones were isolated, and subjected to further screenings. The results of southern blot hybridization of genomic DNA prepared from the positive clone showed the presence of a single gene of CYP1A1, and 3.5 Kb PstI fragment that hybridizes with the most $5^I$-region DNA of CYP1A1 cDNA. The restriction map of PstI fragment was determined by the restriction digestion with various enzymes. The nucleotide sequence of the upstream genomic DNA of CYPIAI was determined by DNA sequencing of exonuclease III unidirectionally deleted PstI fragment DNA using $[^{35}/S]$dATP. This paper presented the upstream genomic DNA of CYP1A1 contained a part of coding region which was about 351 base pairs (from ATG to PstI site at 3563).