• Journal of Life Science
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• v.31 no.6
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• pp.574-580
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• 2021

This study investigated the pathogenicity of different genotypes of infectious hematopoietic necrosis virus (IHNV) strains isolated from infected rainbow trout in Gangwon Province. RtPc0314c and RtPc0314g strains belonging to the JRt-Shizuoka lineage and RtPc0816g strain belonging to the JRt-Nagano lineage showed 100% cumulative mortality when inoculated at a high titer. In addition, more rapid necrosis was observed in rainbow trout infected with RtPc0314c and RtPc0314g mutations. When inoculated at a low titer, 100% mortality was not observed until the end of the experiment, but the mortality was higher in rainbow trout infected with a mutant strain belonging to the JRt-Shizuoka linage than a mutant strain belonging to the JRt-Nagano lineage. A histopathological analysis showed a clear signature of infection in kidney and spleen tissues upon infection with RtPc0314c and RtPc0314g but no signature of infection associated with the Rt03186 strain. Based on the results in this study, it seems that strains belonging to the JRt-Shizuoka lineage in Gangwon Province IHNV are more pathogenic.

• KSBB Journal
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• v.15 no.6
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• pp.658-663
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• 2000

This study is aimed at evaluating the pigmentation of rainbow trout with carotenoid extracts from halophilic bacteria during 8 weeks feeding. Proximate composition of the sample were analyzed. Moisture content was 77% and 73% after 4 and 8 weeks feeding, respectively. Crude protein and lipid content was slowly increased after 8 weeks feeding. But minerals content were not affected with the feeding period and constituents. Muscle carotenoids content of rainbow trout was 0.0223 mg/100g tissue in control group after 4 weeks, and 0.1702 mg/100g tissue in carophyll pink group after 8 weeks. The carotenoids pigmentation content of halophilic bacteria extracts fed group was 0.1256, 0.1382 mg/100g tissue after 8 weeks. It means that the carotenoids of bacteria extracts are a good material for fish pigmentation. The main components of rainbow trout muscle and integuments with these diets were canthaxathin,, zeaxanthin, and ${\beta}$-carotene.

• Journal of Embryo Transfer
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• v.7 no.1
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• pp.31-39
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• 1992

연어류의 종간교배 실험과 LDH, MDH, IDH, $\alpha$GODH, ME 등 다섯가지 isozyme에 대한 genetic marker로서의 활용 가능성을 알아보고자 1차적으로 연어, 산천어 및 무지개송어를 이용하여 종간교배를 실시하였고 이들 세종의 isozyme pattern을 비교하였다. 교배실험은 종간교배, 및 allotriploid 구간 등 12구간으로 나누어 실시하였으며 연어 암컷과 산천어 수컷의 교배결과가 초기성장 단계적에서 가장 우수하게 나타났고이들의 allotriploid도 부활율이 28.1%로 가장 우수하였다. Genetic identification을 위한 isozyme loci 분석결과 연어와 산천어는 대부분의 loci에서 거의 찾아볼 수 없었고 무지개송어는 MDH-B와 IDH에서 다형현상을 확인할 수 있었다. 특히 MDH-B loci는 b 유전자의 출현 빈도에서 세 종간의 식별이 가능하였으며, IDH pattern을 산천어와 무지개송어의 비교에 유효한 것으로 나타났다. 이들 두 loci는 hybrid의 genotype 분석시 유용한 marker로 활용할 수 있는 가능성을 보였고, 앞으로의 어류 육종에 좋은 기초 자료로 이용될 것으로 사료된다.

• Journal of Aquaculture
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• v.20 no.2
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• pp.85-89
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• 2007

This study examined the hatching rate of eyed-eggs and growth of fingerlings of USA strain rainbow trout, Oncorhynchus mykiss, which were transplanted on Nov. 17, 2005 from the USA for improvement of breeding. The diameter and weight of eyed-eggs were $4.95{\pm}0.34\;mm$ and $0.07{\pm}0.003\;g$, respectively. The eyed-eggs were hatched in 8 days later and hatching rates were $77.3{\sim}98.6%$. After 56 days from hatching, the fingerlings grew to $4.0{\pm}0.7$ cm and 0.62 g in total length and body weight, respectively. The relationships between total length (TL) and elapsed days (ED) were expressed as TL=0.0366ED+1.8645 ($r^2=0.928$, n=350). The relationships between body weight (BW) and elapsed days (ED) were expressed as following; $BW=0.0638e^{0.0408ED}\;(r^2=0.9917,\;n=350)$. And survival of rainbow trout was $64.5{\pm}1.3%$ in 56 days after hatching.

• The Korean Journal of Zoology
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• v.36 no.1
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• pp.77-83
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• 1993

난모세포성숙기 (peripheral germinal vesicle stage)의 무지개송어(Oncorhynchus mykiss)를 대상으로 방사성 표지 전구체(3H-pregnenolone, 3H-l7$\alpha$-hydroxyprogesterone 그리고 3H-androstenedione)를 이용하여 유 nitro에서 관찰한 협막세포층의 스테로이드 주 대사 경로는 다음과 같으며, pregnenolone -) 17a-hydroxypregnenolone$\longrightarrow$ 17u-hydroxyprogesterone $\longrightarrow$ androstenedione $\longrightarrow$ testosterone 이는 $\Delta$5-스테로이드 경로의 존재가능성을 지적하고 있다.

• Journal of Aquaculture
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• v.13 no.1
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• pp.79-85
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• 2000

The effects of estrogen and androgens on Vg gene expression were examined in primary hepatocyte culture and livers of the immature male trout. Specific primers of Vg cDNA were designed with already reported Vg gene nucleotide sequences. PCR product was sequenced and verified with Vg cDNA of rainbow trout. Total RNA was extracted from the cultured hepatocytes and livers of steroid-treated rainbow trout and then it was analyzed by reverse transcriptase- polymerase chain reaction (RT-PCR) analysis. The Vg mRNA and Vg protein synthesis were increased in rainbow trout in vivo and in vitro with E$_2$ and methyltestosterone (MT) There were dose and time-related effects of E$_2$ and MT on vitellogesis. Androgens such as progesterone androsterone and testosterone also stimulated Vg mRNA expression in vitro. The results show that androgens as well as E$_2$ can induce expression of Vg mRNA in trout in vivo and in vitro.

• 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.

• Journal of Life Science
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• v.13 no.1
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• pp.128-135
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• 2003

102 ESTs (Expressed Sequence Tags) were obtained by sequencing clones from a library of rainbow trout kidney cDNAs. Of the sequences generated, 55.8% of the ESTs were represented by 37 known genes. The 45 clones of unknown gene products potentially represent 40 novel genes. The genes involved in structural function (14.5%) and transcription/translation (11.6%) account for the major gene expression activities in the kidney Microarray experiment was conducted to compare gene expression of the unique ESTs in young and adult rainbow trout kidneys. While mitochondrion, cytochrome b, rho G, spastin protein, and three unknown genes were down-regulated in the mature fish kidney, calponin 1, calcium binding protein, histone deacetylase 1, and an unknown gene were up-regulated in the mature fish kidney. This research demonstrates the feasibility and power of functional genomics in rainbow trout.

• 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.

• 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.