• Korean Journal of Ichthyology
• /
• v.3 no.1
• /
• pp.58-62
• /
• 1991

The genomic DNA from liver tissue of rainbow trout(Oncorhynchus mykiss) was analyzed by agarose gel electrophoresis. The molecular weight of Oncorhynchus mykiss genomic DNA was about 21.3 kilobase pairs.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.2
• /
• pp.103-113
• /
• 2014

This study compared the food quality of freshwater rainbow trout Oncorhynchus mykiss cultured (in Pyeongchang, Pyeongtaek, Jecheon and Geochang) with that of imported salmon Oncorhynchus keta. The proximate composition of the four types of rainbow trout was 74.4-75.7% moisture, 18.3-19.4% crude protein, 3.1-4.3% crude lipid, and 1.3-1.7% ash. There were slight differences in the proximate composition of the four types of rainbow trout. No significant (P>0.05) differences were found in the red color and odor and taste intensities of the four types of rainbow trout based on the Hunter a values, volatile basic nitrogen content, odor intensity using an electronic nose and taste intensity using an electronic tongue. The crude protein, total amino acid, and mineral contents of rainbow trout cultured in Pyeongtaek were superior or similar to those of the trout cultured in the other three places. The rainbow trout cultured in Geochang had the highest hardness, at 858.5 g.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.50 no.5
• /
• pp.621-623
• /
• 2017

Mariculture of rainbow trout Onchorhynchus mykiss has been initiated in or around olive flounder Paralichthys olivaceus farms, where viral hemorrhagic septicemia virus (VHSV) is often detected in some fish. In the present study, we investigated VHSV infection in seawater-reared rainbow trout because VHSV has never been detected in salmonids in Korea. A total of 104 adult fish were tested for the presence of VHSV by reverse transcription-polymerase chain reaction, followed by virus isolation with the fathead minnow caudal trunk cell line. Cytopathic effects were observed in two samples but the virus was identified as infectious hematopoietic necrosis virus. Thus, VHSV was not isolated from seawater-reared rainbow trout.

• Journal of Aquaculture
• /
• v.11 no.2
• /
• pp.279-282
• /
• 1998

Effects of high concentration of intracellular calcium on estradiol-induced vitellogenin(VTG) induction were examined using ouabain in Primary hepatocyte culture in the rainbow trout Oncorhynchus mykiss. Ouabain increases cytosolic free calcium as a result of inhibition of $Na^+ - Ca^{2+}$ exchanger. Ouabain markedly reduced VTG production to the control level, despite of calcium concentrations in the incubatin medium. Therefore, ouabain would reduce VTG production not by increasing intracellular calcium bt directly by inhibiting $Na^+ - K^+$ ATPase.

• Korean Journal of Ichthyology
• /
• v.27 no.3
• /
• pp.183-188
• /
• 2015

Recently, mariculture of rainbow trout (Oncorhynchus mykiss) has been initiated in the coast areas of Korea. In the present study, we investigated the effect of fish viruses on mariculture of rainbow trout. The pathogenicity of infectious hematopoietic necrosis virus (IHNV) and infectious pancreatic necrosis virus (IPNV) isolated from freshwater rainbow trout was tested against major cultured marine fish species, including olive flounder (Paralichtys olivaceus), rock fish (Sebastes schlegeli), rock bream (Oplegnathus fasciatus), red seabream (Pagrus major) and sevenband grouper (Epinephelus septemfasciatus). The pathogenicity of marine birnavirus (MABV), hirame rhabdovirus (HIRRV) and nervous necrosis virus (NNV) isolated from marine fish species was also tested against rainbow trout. No mortality was observed in marine fish species challenged with IHNV or IPNV. However, olive flounder and rock bream were infected by IHNV and IPNV. A mortality of 8.3% was observed in rainbow trout challenged with HIRRV. The fish was infected by both MABV and NNV. These results suggest that the mariculture of rainbow trout might be affected by fish viruses.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.2
• /
• pp.109-116
• /
• 2010

This study investigated the effects of astaxanthin, which is used to improve the muscle color of fish, on the nutritional composition of rainbow trout (Oncorhynchus mykiss). The trout were fed extruded pellets containing astaxanthin (pigmented rainbow trout) or without astaxanthin (non-pigmented rainbow trout). No significant differences in the contents of crude protein and crude ash between the two muscles of the two groups were observed. However, the crude fat composition of the muscle of pigmented rainbow trout was about two times higher than that of control muscle. In the muscle of pigmented rainbow trout, the contents of docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3), which are functional polyunsaturated fatty acids, were 1.6 fold higher than in non-pigmented muscle. In addition, the contents of minerals such as Zn and Fe, vitamins (B group, C, and E), free amino acids, carotenoids and astaxanthin were increased in the muscle of rainbow trout fed pellets supplemented with astaxanthin. Specifically, the content of the bioactive compound astaxanthin, was increased six times in the pigmented muscle, as compared to the control muscle. The results suggest that a diet supplemented with astaxanthin improves the nutritional composition of rainbow trout muscle as well as improving the muscle color.

• Fisheries and Aquatic Sciences
• /
• v.15 no.1
• /
• pp.83-89
• /
• 2012

Flavobacterium johnsoniae was isolated from farmed rainbow trout Oncorhynchus mykiss in Korea, and its biochemical and molecular characterization was determined. Yellow-pigmented bacterial colonies were isolated from 18 of 64 fish samples (28.1%) on trypticase soy agar plates, and their biochemical profiles were characterized by API 20E and API 20NE test kits. F. johnsoniae was identified by biochemical phenotyping of factors including rapid gliding motility, Gram-negative condition, oxidase- and catalase-positive status, Congo red absorption, nitrate reduction, ${\beta}$-galactosidase production, acid production from glucose, and gelatin and casein hydrolysis. PCR and subsequent sequencing of 16S rRNA confirmed that the yellow-pigmented colonies were most similar to F. johnsoniae. The alignment analysis of 16S rRNA sequences also showed that all 18 rainbow trout isolates had highly similar homologies (97-99% identity). One isolate was selected and named FjRt09. This isolate showed 98% homology with previously reported F. johnsoniae isolates, and in phylogenetic analysis was more closely grouped with F. johnsoniae than with F. psychrophilum, F. columnare, or F. branchiophilum. This is the first report on the occurrence and biochemical characterization of F. johnsoniae isolated from rainbow trout in Korea.

• Fisheries and Aquatic Sciences
• /
• v.14 no.2
• /
• pp.89-92
• /
• 2011

We investigated the antioxidant and cholinesterase inhibitory activities of the aqueous extract of rainbow trout Oncorhynchus mykiss. The antioxidant activity of O. mykiss aqueous extract was determined by in vitro peroxynitrite scavenging activity and reducing power assays. The aqueous extract of O. mykiss showed potent peroxynitrite radical scavenging activity ($IC_{50}=0.12{\pm}0.001\;mg/mL$) and reducing power (absorbance=$0.47{\pm}0.001$) at the concentration of 1 mg/mL. The in vitro cholinesterase inhibitory activity of O. mykiss aqueous extract was examined using spectrophotometric analyses of acetyl- and butyrylcholinesterase. The aqueous extract of O. mykiss showed acetylcholinesterase inhibitory activity ($IC_{50}=1.61{\pm}0.13\;mg/mL$), but did not exhibit inhibitory activity against butyrylcholinesterase. These results suggest that O. mykiss possesses antioxidant and acetylcholinesterase inhibitory activities and provide scientific evidence for the health benefits of O. mykiss aqueous extract.

• BMB Reports
• /
• v.38 no.2
• /
• pp.206-210
• /
• 2005

Gonadogenesis is a complicated process which involves multi-gene interactions. A rainbow trout (Oncorhynchus mykiss) gene spermatogenesis associated 4 (SPATA4) was cloned and characterized from adult rainbow trout testis. The cDNA sequence of rainbow trout SPATA4 contains an open reading frame of 1, 081 nucleatides encoding a putative protein of 259 amino acids. The putative protein from rainbow trout shares a 76.8% homology with zebrafish SPATA4. No trans-membrane regions or signal peptide were detected using bioinformatics methods. Subcellular localization analysis revealed that rainbow trout SPATA4 was a nuclear protein with highest possibility (39.1%). Multi-tissue reverse transcriptase PCR (RT-PCR) was performed to examine the distribution of rainbow trout SPATA4 in eleven organs of adult rainbow trout. The result demonstrated that this gene express specifically in testis and slight amount of expression was detected in ovary. Further analysis of SPATA4 characterization and function in rainbow trout may provide insight into the understanding of gonadogenesis process.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.5
• /
• pp.676-684
• /
• 2021

Euryhaline teleost have extraordinary ability to deal with a wide range of salinity changes. To study the seawater adaptability of rainbow trout Oncorhynchus mykiss (body weight 638±54 g, length 38.6±2 cm) to salinity increase fish were transferred from freshwater to 7, 14, 21, 28 and 32 psu and checked for mortality over 5 days. No mortality was observed in 0-32 psu. In fish transferred to 0-32 psu, blood osmolality was maintained within physiological range. The changes of serum enzyme activities (aspartate transaminase, AST and alanine transaminase, ALT) showed no significant level during experimental period. To explore the underlying molecular physiology of gill and kidney responsible for body fluid regulation, we measured mRNA expression of five genes, Na⁺/K⁺/2Cl^- cotransporter1 (NKCC1), aquaporin3 (AQP3), cystic fibrosis transmembrane conductance regulator (CFTR), glucocorticoid receptor (GR) and growth hormone receptor (GHR) in response to salt stress. Based on our result, rainbow trout could tolerate gradual transfer up to 32 psu for 5 days without mortality under physiological stress. This study suggests to alleviate osmotic stress to fish, a gradually acclimation to increasing salinity is recommended.