• Journal of Life Science
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• v.5 no.2
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• pp.14-14
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• 1995

The effect of lipoxygenase (LOX) on the oxidation and co-oxidation of lipid fraction was studied in the model system of rainbow trout. For the reaction in model system 1 g of lipid fraction and 50mL of enzyme extract(LOX, 140 unit in 50mL phosphate buffer solution at pH 7,4)), which were obtained from rainbow trout, were homoginized in the presence of Tween 20 and kept at 23$\circ$C for 3 days. The activity of LOX was decreased to 43% of initial level during the reaction in the model system. The initial composition of rainbow trout lipid was showed to be consisted of trigliceride(TG;82%) and free fatty acid(FFA;0.1%), while this converted to 59% of TG and 20% of FIFA, respectively after reaction in model system. Change of fatty acid composition was also observed and the content of linoleic acid, one of the major fatte acids, was decreased to 13% from 54% in the content of total fatty acids after reaction. The carotenoids in rainbow trout were composed of 0.4% $\alpha$-carotene, 1.6% $\beta$ -carotene, 80% canthaxanthin, 7% lutein and 11% zeaxanthin, thus the canthaxanthin was the major component. This canthaxanthin was the most degraded carotenoid by lipoxygenase catalyzed co-oxidation during the reaction. On the other hand the tocopherol isomers found in the rainbow trout were $\alpha$ and $\beta$ -tocopherol, and $\alpha$-tocopherol had a higher degradation rate by the lipoxygenase catalyzed co-oxidation than of $\beta$-tocopherol in the reaction of model system.

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

• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1244-1247
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• 2007

Effects of muscle fluid concentrates from Styela clava on fish diets were investigated in rainbow trout(Oncorhynchus mykiss). Fish were fed on one of the isonitrogenous(48%) and isolipic(20%) feed containing 5 to 20% of muscle fluid concentrates for 8 weeks. Hematological parameters such as hemoglobin, hematocrit, albumin, glucose, total bililubin, triglyceride and glutamic pyruvate transaminase of the rainbow trout which were fed on the diets varied, but no specific trend became apparent. However, glutamic oxaloacetic transaminase value was significantly higher than that of normal fishes. Therefore, concentrated ascidian fluid which is normally discarded, can be combined with commercial diets for the normal growth of rainbow trout.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.624-629
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• 2017

A rainbow trout Onchorhynchus mykiss farm located in Gangwon province, South Korea, experienced approximately 10% mortality in June 2017. Most diseased fish had a markedly distended, gas-filled stomach, and exhibited abnormal behavior at the water surface. In this study, we attempted to identify the cause of stomach distension syndrome in those rainbow trout. The stomach of most of the affected fish were full of unidentified gases and some exudate, and yeast was isolated from the stomach mucosa. Pure cultures of yeast were identified using a multilocus sequence typing scheme based on 18S rRNA, internal transcribed spacers, large subunit rRNA, and the gene encoding the largest subunit of RNA polymerase II (RPB1). The RPB1 gene sequences were compared with those of related species available in a database. The yeast was identified as Scheffersomyces coipomoensis (Candida coipomoensis) based on sequence analyses. This is the first study to reveal that Sch. coipomoensis is a potential causative agent of stomach distension syndrome in farmed rainbow trout. Our results will be helpful for future related studies, and indicate that farmers and stakeholders should observe this emerging disease closely.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.19-23
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• 1998

Effects of pituitary and thyroid hormones on estradiol-induced vitellogenin (VTG) induction were electrophoretically examined in primary hepatocyte cultures of rainbow trout. Hepatocytes were precultured for 2 days and then estradiol-17 $\beta$ $(E_2,\;2 \times 10^{-6}M)$>, triiodothyronine $(T_3,\;10^{-8}-10^{-6}M)$, bovine growth hormone (bGH, 10-100 ng/ml), ovine prolactin (oPRL, 100-500 ng/ml), and pituitary extract (PE) of rainbow trout (0.75PE/dish) were added to the incubation medium. The hepatocytes were cultured for 7 more days. The addition of oPRL to the incubation medium was not effective in increasing VTG production at any concentrations. The addition of PE to the incubation medium with $E_2$ was not effective in increasing VTG production. The addition of bGH to the incubation medium with $E_2$ was not effective in increasing the rate of VTG production at concentrations of 10-50 ng/ml. However, a higher concentration of bGH, 100 ng/ml, increased VTG production. The various concentrations of $T_3$ were ineffective in stimulating VTG production. These results suggest that GH could be one of stimulus factors for VTG production in rainbow trout.

• The Korean Journal of Food And Nutrition
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• v.29 no.1
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• pp.33-36
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• 2016

Carbonic anhydrase is essential for the cellular transportation of hydrogen and bicarbonate ions and plays a key role in a wide variety of physiological processes. Rainbow trout, Oncorhynchus mykiss is an important freshwater fish in aquaculture industry and is known to be one of the most susceptible species to environmental contamination. In this study, carbonic anhydrase was detected in the kidney and intestine of rainbow trout. Carbonic anhydrase was isolated from cytosolic proteins and identified by using SDS-PAGE, isoelectric focusing, and immunohistochemical methods. A specific protein band with molecular weight of 30 kDa and pI of 7.0 was detected by Western blotting. The immunohistochemical results showed that carbonic anhydrase was located at various cells in the kidney and intestine of rainbow trout.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.4
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• pp.819-827
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• 2013

Water quality has been considered to be one of sanitation standard operating procedures (SSOP) for hazard analysis critical control points (HACCP) application in aquaculture farms. This study was conducted to evaluate a hazard caused by water used in aquaculture farm of rainbow trout. The water quality was analyzed to investigate both physiochemical and bacteriological level in water samples collected from aquaculture farm of rainbow trout, Oncorhynchus mykiss. No significant difference were observed on water temperature and pH from season to season. However, the levels of dissolved oxygen were decreased as the outside temperature was increased, even if the levels were adequate for aquaculture. Also, other physiochemical analysis including biochemical oxygen demand (BOD), chemical oxygen demand (COD) and suspended solid (SS) revealed that the waters for aquaculture analyzed in this study was suitable for rainbow trout aquaculture. The bacterial analyses were also revealed that the waters for aquaculture were met to both coliform group (<18 MPN/100mL) and viable cell count (<100 CFU/mL). However, some of waste waters from aquaculture farms showed higher levels of BOD and COD than those of waste water standard (<2 ppm), suggesting that regular cleaning of fish tank and precipitation tank is needed.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1355-1359
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• 2003

This study examined the replacement of the fish meal (FM) with commercial poultry by-product meal (PBM) in practical diets for rainbow trout (Onchorynchus mykiss, Walbaum). Five isocaloric and isonitrogenous diets containing levels 0 (control), 10, 20, 30 and 40% of PBM as a replacement for FM were fed to three replicate groups of rainbow trout with a initial weight $34.50{\pm}0.43g$ (mean${\pm}$SE). Protein efficiency ratio (PER) of diets containing PBM up to 20% were similar to the control while significantly lower values were obtained from the groups receiving higher levels of PBM (p<0.05). Apparent protein digestibility coefficients (ADCs) were significantly lower than that of the control group when PBM was included at level of 20% or more. Similarly, significantly lower values were observed with diets containing 30 and 40% PBM in terms of dry matter, organic matter, ether extract, ash and energy digestibility (p<0.05). Dietary treatments did not significantly affect the body composition of the fish in terms of dry matter, crude protein, ether extract and ash. In conclusion, PBM in a proportion of 20% may replace about 40 % of FM in rainbow trout diet without significant impairment grow.

• Ocean and Polar Research
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• v.38 no.2
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• pp.103-113
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• 2016

This study aimed to examine the role of two aquaporin isoforms (AQP3 and AQP8) in response to the hyperosmotic challenge of transitioning from freshwater (FW) to seawater (SW) during parr and smoltification (smolt) using the rainbow trout, Oncorhynchus mykiss. We examined the changes in the expression of AQPs mRNAs in the gills and intestine of the parr and smolt stages of rainbow trout transferred from FW to SW using quantitative real-time PCR in an osmotically changing environment [FW, SW, and recombinant AQP3 (rAQP3) injection at two dosage rates]. Correspondingly, AQPs were greater during smoltification than during parr stages in the rainbow trout. Plasma osmolality and gill $Na^+/K^+$-ATPase activity increased when the fish were exposed to SW, but these parameters decreased when the fish were exposed to SW following treatment with rAQP3 during the transition to seawater. Our results suggest that AQPs play an important role in water absorbing mechanisms associated with multiple AQP isoforms in a hyperosmotic environment.

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