• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.232-239
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• 1994

In order to determine the utilization of ascidian tunic, which has been blamed for problems of costal environmental pollution when discharged into the sea after being used as a natural dietary pigment sources for rainbow trout(Oncorhynchus mykiss), fingerlings were fed on experimental diets containing acetone-extracts for 6 weeks. The amounts of acetone-extracts were 11,000mg/Kg and contained 50mg/100g wet tissues of carotenoid and $6\%$ of carotenoids were astaxanthin. From the results of feeding experiments, the growth rate in the extract group was a little higher than that of the control and pink groups after 6 weeks. The redness and yellowness of the fish skin and muscle in the extract group were similar to the pink group. Therefore, acetone-extracts of ascidian tunic were judged to be a natural dietary pigment source suitable as a substitute synthetic pigment for aquaculture use.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.469-474
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• 1995

The effects of sperific inhibitors of $3\beta-hydroxy-\Delta^5-steroid\;dehydrogenase$ $(3\beta-HSD;\;an\;enzyme\;catalyzing\;conversion\;of \Delta^5\;steroids\;to\;\Delta^4 steroids),$ cyanoketone and trilostane, on $^3H-pregnenolone$ metabolism in isolated ovarian thecal layers have been investigated in vitro. At all doses of cyanoketone $(10^{-5}\;and\;10^{-4}\;M)$ and trilostane $(10^{-5}\;and\;10^{-4}\;M)$ $(3\beta-HSD$ enzyme activity that transforms pregnenolone to $17\alpha-hydroxyprogesterone$ was inhibited in the thecal layers. Trilostane appeared to be more efficient than cyanoketone. Trilostane at doses of $10^{-8},\;10^{-7},\;10^{-6},\;and\;10^{-5},\;M/ml$ caused a dose-response inhibition of $\Delta^4$ steroids accumulation in the medium from pregnenolone, but not completely blocked the conversion of $\Delta^5\;to\;\Delta^4$ steroids.

• Journal of Aquaculture
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• v.17 no.1
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• pp.69-80
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• 2004

The objective of the present study was to analyze genetic distances, variation and characteristics of individuals in rainbow trout, Oncorhynchus mykis using amplified fragment length polymorphism (AFLP) method as molecular genetic technique, to detect AFLP band patterns as genetic markers, and to compare the efficiency of agarosegel electrophoresis (AGE) and polyacrylamide gel electrophoresis (PAGE), respectively. Using 9 primer combinations, a total of 141 AFLP bands were produced, 108 bands (82.4%) of which were polymorphic in AGE. In PAGE, a total of 288 bands were detected, and 220 bands (76.4%) were polymorphic. The AFLP fingerprints of AGE were different from those of PAGE. Separation of the fragments with low molecular weight and genetic polymorphisms revealed a distinct pattern in the two gel systems. In the present study, the average bandsharing values of the individuals between two populations apart from the geographic sites in Kangwon-do ranged from 0.084 to 0.738 of AGE and PAGE. The bandsharing values between individuals No.9 and No. 10 showed the highest level within population, whereas the bandsharing values between individuals No.5 and No.7 showed the lowest level. As calculated by bandsharing analysis, an average of genetic difference (mean$\pm$SD) of individuals was approximately 0.590$\pm$0.125 in this population. In AGE, the single linkage dendrogram resulted from two primers (M11+H11 and M13+H11), indicating six genetic groupings composed of group 1 (No.9 and 10), group 2 (No. 1, 4, 5, 7, 10, 11, 16 and 17), group 3 (No. 2, 3, 6, 8, 12, 15 and 16), group 4 (No.9, 14 and 17), group 5 (No. 13, 19, 20 and 21) and group 6 (No. 23). In AGE, the genetic distances among individuals of between-population ranged from 0.108 to 0.392. In AGE, the shortest genetic distance (0.108) displaying significant molecular differences was between individuals No.9 and No. 10. Especially, the genetic distance between individuals No. 23 and the remnants among individuals within population was highest (0.392). Additionally, in the cluster analysis using the PAGE data, the single linkage dendrogram resulted from two primers (M12+H13 and M11+H13), indicating seven genetic groupings composed of group 1 (No. 15), group 2 (No. 14), group 3 (No. 11 and 12), group 4 (No.5, 6, 7, 8, 10 and 13), group 5 (No.1, 2, 3 and 4), group 6 (No.9) and group 7 (No. 16). By comparison with the individuals in PAGE, genetic distance between No. 10 and No. 7 showed the shortest value (0.071), also between No. 16 and No. 14 showed the highest value (0.242). As with the PAGE analysis, genetic differences were certainly apparent with 13 of 16 individuals showing greater than 80% AFLP-based similarity to their closest neighbor. The three individuals (No. 14, No. 15 and No. 16) of rainbow trout between two populations apart from the geographic sites in Kangwon-do formed distinct genetic distances as compared with other individuals. These results indicated that AFLP markers of this fish could be used as genetic information such as species identification, genetic relationship or analysis of genome structure, and selection aids for genetic improvement of economically important traits in fish species.

• Journal of fish pathology
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• v.23 no.1
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• pp.1-8
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• 2010

Infectious hematopoietic necrosis virus (IHNV) is the causative agent of IHN, one of the most serious viral diseases of salmonid fish. In this study, glycoprotein (G) gene nucleotide sequence of isolated IHNV RtWanju09 from Jeollabuk-do province was analyzed to evaluate their genetic relatedness to worldwide isolates. As the result, it was revealed that IHNV RtWanju09 isolate belongs to JRt Shizuoka lineage with IHNV RtPy91 and RtJe00. The genetic diversity of G gene between RtWanju09 isolate and RtPy91 isolate from Gangwon-do province was 1.77% and maximum nucleotide diversity among the JRt Shizuoka lineage in Korea was 3.03% during the past 20 years, supporting that the continuous evolution has been occurred among JRt Shizuoka isolates. It was believed that IHNV RtWanju09 isolate has been introduced by the movement of contaminated eggs with IHNV from Gangwon-do to Jeollabuk-do by the reason that the eyed eggs in Jeollabuk-do province used to be obtained from Gangwon-do province. In this study, the domestic transfer of IHNV was firstly investigated by the transfer history of eggs and the phylogenetic analysis using IHNV glycoprotein gene sequence.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.131-136
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• 1995

An attempt was made to elucidate the stability of serum metabolites and enzyme activities in blood samples taken from rockfish(Sebastes schlegeli), Israeli carp(Cyprinus carpio) and rainbow trout Oncorhynchus mykiss) under different storing conditions. The concentrations of total protein(TP), albumin(ALB), triglyceride(TG), cholesterol(CHOL) glucose(GLC), phosphorus(P) and sodium(Na), and the activities of alanine aminotransferase(ALT) and aspartate aminotransferase(AST) in serum were investigated for 16 days at $15^{\circ}C$(room temp.) and $4^{\circ}C$ (refrigerative) condition, or frozen at $-20^{\circ}C$ for period of 30 days. Though there was a little difference between fish species, the concentrations of TP, ALB, GLC, P, Na in serum were stable at all storing temperatures, while those of TG, CHOL, ALT and AST were not stable, particularly even at the normal temperature. In general, serum components were more stable at refrigerative and frozen conditions than at room temp. storing. However, it was noticeable that the stability of CHOL in rockfish serum was found to be more unstable at $-20^{\circ}C$ than kept at $15^{\circ}C$ or$4^{\circ}C$.

• Journal of Aquaculture
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• v.5 no.1
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• pp.1-7
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• 1992

Digestion rates of protein, carbohydrate, and lipid in the two kinds of extruding processed soybean meals, heated (H-SBM) and raw (R-SBM), were tested for evaluate the effectiveness of soybean meal in the rainbow trout diet. The relation between digestion rate of protein and trypsin inhibitor (TI) was also determined. The protein digestion rate of both H-SBM and R-SBM were increased up to $95{\%}$ by extruding process compared to the none treated soybean meal. The digestion rate of carbohydrate in R-SBM was increased by extruding process whereas the one in H-SBM was not. The activity of trypsin inhibitor was almost diminished by the extruding process and digestion rate of dietary protein was improved. However, the reason of this improvement was not clear whether caused by the deactivation of trypsin inhibitor.

• Journal of fish pathology
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• v.37 no.1
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• pp.147-153
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• 2024

The World Organization for Animal Health (WOAH) recommends two protocols (ITS and COI) for conventional PCR of G. salaris diagnosis. However, ITS PCR protocol may yield false-positive results, leading to unnecessary countermeasures. It's difficult to distinguish between G. salaris and false-positive by similar amplicon size of PCR, since the amplicon size of ITS PCR in G. salaris and false-positive was 1,300 and 1,187 bp, respectively. The nucleotide sequences of ITS false-positive in rainbow trout is 99.7% identical to previously reported host genome sequences of rainbow trout (Oncorhynchus mykiss) and 95.3 to 89.1% identical to those of other salmonid fish species. To reduce false-positive PCR band, PCR was performed by the different annealing temperature, but PCR bands were still detected. In RFLP analysis by HaeIII, the PCR product of G. salaris was digested into four bands of 512, 399, 234 and 154 bp, while the false-positive was digested into seven bands of 297, 263, 242, 144, 93, 80 and 68 bp. In the RFLP patterns digested by HindIII, G. salaris showed two bands of 659 and 640 bp, while false-positive had one fragment of 1,187 bp without any digestion. Therefore, the RFLP method of ITS PCR with HaeIII and HindIII can be used for differentiation between G. salaris and false-positive. These results might provide important information on the improvement of PCR diagnostic method of G. salaris.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.3
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• pp.357-368
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• 1996

To utilize the ascidian tunic as a natural pigment and dietary sources for rainbow trout (Oncorhynchus mykiss), juvenile were fed on experimental diets containing enzymatic hydrolysates of ascidian tunic treated with three commercial mined enzymes (ultrazyme, cellulase, viscozyme) for 12 weeks. From the results of feeding experiment, similar growth rate was checked in the enzymatic hydrolysis group compared with control, and those were a higher than of ascidian tunic powder group. The total acetone extractable pigment in muscle of the enzymatic hydrolysates group was lower than that of the ascidian extracts group and carophyll pink group until 8 weeks, but the level of those pigment of the enzymatic hydrolysates was similar to the ascidian extracts and carophyll pink group after 12 weeks. The lipid content was increased with the pigment concentration in the all experimental group. But the ascidian tunic pigment did not influence on the composition of the fatty acids in the muscle and liver. From the consideration of results for pigmentation, the enzymatic hydrolysates of ascidian tunic were suitable for both a natural pigment and dietary protein and carbohydrates sources as a substitute synthetic pigment for aquaculture use.

• Journal of fish pathology
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• v.30 no.2
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• pp.79-88
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• 2017

At the present, fish farms are suffering a lot of economic losses due to infectious diseases caused by various pathogens including aeromonad. Aeromonad is ubiquitous bacteria that causes infectious diseases. At least 26 species in the genus Aeromonas have been reported to cause fatal infections not only in salmonid fishes, but also in other freshwater and seawater fishes. Molecular techniques based on nucleic acid sequences of 16S rDNA and housekeeping genes can be used to identify the Aeromonas species. In this study, The genus Aeromonas was isolated from salmonid fishes of sixteen fish farms in Gangwon-Do, Korea and phylogenetically identified based on the sequences of 16S rDNA and housekeeping genes for Aeromonad, i.e. RNA polymerase sigma factor ${\sigma}^{70}$ (rpoD) or DNA gyrase subunit B (gyrB). Consequently, 96 strains were collected from Atlantic salmon (Salmo salar), coho salmon (Oncorhynchus kisutch), masou salmon (Oncorhynchus masou) and rainbow trout (Oncorhynchus mykiss), and 36 isolates were identified as the genus Aeromonas by 16S rDNA analysis. Thirty six Aeromonad isolates were further analysed based on rpoD or gyrB gene sequences and found Aeromonas salmonicida (24 isolates), A. sobria (10 isolates), A. media (1 isolates) and A. popoffii (1 isolates), indicating that A. salmonicida is a main infectious bacteria in Salmonid fishes in Gangwon-Do. It was also proved that the phylogenetic identification of Aeromonas species based on the sequences of housekeeping gene is more precise than the 16S rDNA sequence.

• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.118-124
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• 2012

The present study was conducted to investigate different gene expression profile between treated poMSTNpro and non-treated in rainbow trout and to identify those genes that are specifically or predominantly expressed in treated poMSTNpro by employing annealing control primer (ACP)-based GeneFishing polymerase chain reaction (PCR). We isolated total RNAs in muscle tissues from the treated poMSTNpro fish by immersion bath technique with fish myostatin prodomain (Paralichthys olivaceus, poMSTNpro) for one month and the other was non-treated poMSTNpro, and synthesized cDNA using annealing control primers (ACP, Seegene, Korea). Using 20 different ACPs for PCR, were cloned sequenced, and analyzed identities of 2 differentially expressed genes (DEGs). According to BLAST analysis, sequences of 2 clones significantly matched database entries and confirmed by semi-quantitative RT-PCR. The functional roles of one up-regulated gene, cytochrome P450 mono-oxygenases 2K1v2 (CYP2K1v2), and one down-regulated gene was Profilin-1 were identified. We identified distinctive gene expression profiles in improved rainbow trout growth by treatment with a fish myostatin prodomain using ACP-based GeneFishing.