• 한국어병학회지
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• 제31권1호
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• pp.1-8
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• 2018

Causative agent of infectious hematopoietic necrosis (IHN) belonging to genus Novirhabdovirus (Rhabdoviridae). Economic losses caused by IHNV are serious in mainly Oncorhynchus spp. including rainbow trout O. mykiss and Atrantic salmon Salmo salar. IHNV was initially found by endemic presence in U.S. West Coast for sockeye salmon fry O. nerka and chinook salmon fry O. tshawytscha in the 1950s, and it has spread to Japan, Korea and Taiwan in the 1970s, and also to Italy and France in the 1990s. Currently, IHNV is detectable in many parts of the world, including Russia and South America. Mortality due to IHNV infection in fish with ${\leq}0.5g$ of body weight reaches 60% to 100%, while the mortality reduces by fish growing. In recent years, onset of IHNV infection has increased also in fish with large sizes. Here, we introduce molecular epidemiology and virulence changes of IHNV in East Asia, furthermore, we discuss on future prospects in IHNV researches.

• 한국어병학회지
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• 제31권2호
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• pp.57-70
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• 2018

Infection with salmonid alphavirus (SAV) is a serious disease that mainly affects rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar L.) reared in seawater or freshwater. SAV is prevalent in European countries including Norway that exports rainbow trout and Atlantic salmon to Korea. Consequently, SAV was listed as a disease notifiable to the OIE and many salmonid-producing countries either designate SAV as their notifiable disease or do research on the development of diagnosis and epidemiology to reduce the possibility of SAV infection. Unlike other salmonid-producing countries, SAV is not listed as a notifiable disease in Korea, thereby arousing concern that SAV will get into the country through the importation of live salmonids. Under the circumstance, Korea needs to have a legal basis to take much stricter follow-up measures, including listing SAV as a notifiable disease, establishing surveillance system based on OIE standards to declare Korea free from SAV, killing infected fish and conducting fallow system against affected farms.

• Fisheries and Aquatic Sciences
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• 제26권7호
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• pp.447-454
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• 2023

Fast somatic growth is important considerations for successful and competitive aquaculture industry. In rainbow trout reared in South Korea, triploid induction was used to suppress negative influence of reproductive maturation to body growth. However, the effects of triploidy are visible in both mature fish and developing juvenile fish. Thus, it is also important to explicate the effect of triploid induction on growth during the early-life stages of rainbow trout-alevins and fry. Rainbow trout fertilized eggs were subjected to triploid induction and polyploidy was checked by flow cytometry. Diploid and triploid alevins and fry were reared separately in tanks with constant flow of freshwater through flow-through water system and growth measurements were done from zero days after hatching (DAH 0) until DAH 134. The egg-yolk morphometrics of alevins-yolk length, yolk height, yolk volume and yolk weight-were statistically similar (p > 0.05) in both genotypes from DAH 0 to DAH 22. The total length, body height, and body weight of alevins and fry were statistically better (p > 0.05) in both genotypes until DAH 92 but thereafter, triploid had a significantly better growth performance (p < 0.05) over diploid fish until the completion of study at DAH 134. With that, triploid induction did not influence alevin yolk regions and body growth and fry somatic growth until around 3 months after hatching, but considerable growth enhancement was subsequently apparent.

• 한국어병학회지
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• 제36권2호
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• pp.389-394
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• 2023

Infectious hematopoietic necrosis virus (IHNV) is s significant viral pathogen affecting cultured rainbow trout (Oncorhynchus mykiss) in Korea. In this study, five monoclonal antibodies (mAbs) (IHNV-1, 2, 3, 4, and 5) were produced using purified IHNV. Reactivities of these mAbs were analyzed by western blot (WB), enzyme-linked immunosorbent assay (ELISA), and indirect fluorescent antibody test (IFAT). These mAbs recognized glycoprotein (69 kDa, IHNV-1), nucleocapsid protein (39 kDa, IHNV-3, 4, and 5), or phosphoprotein (27 kDa, IHNV-2) of IHNV by WB analysis. ELISA results indicated that these five mAbs were specific to IHNV without showing any cross-reactivity against other fish viruses (hirame rhabdovirus, infectious pancreatic necrosis virus, and viral hemorrhagic septicemia virus). IFAT demonstrated specific fluorescence signals of IHNV-infected epithelioma papulosum cyprini (EPC) cells, whereas no reactivity of normal EPC cells was observed. These mAbs can be very useful for immuno-diagnosis of IHNV infection.

• 한국양식학회지
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• 제17권1호
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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.

• 한국어류학회지
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• 제31권2호
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• pp.90-100
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• 2019

본 연구는 평창의 남한강 지류 기화천에 출현하는 어류 군집 구조 및 Phoxinus phoxinus와 Rhynchocypris kumgangensis의 분포 특성을 파악하고자 2013년 3월부터 11월까지 조사하였다. 조사기간 동안 총 6과 19종의 어류가 출현하였으며, 개체수 및 생체량 우점종은 R. kumgangensis (Individuals 44.7%, Biomass 30.2%), 아우점종은 P. phoxinus (Individuals 27.7%, Biomass 15.9%)이었다. 고유종은 Pseudopungtungia tenuicorpus, Coreoleuciscus splendidus, Hemibarbus mylodon, Gobiobotia brevibarba, Microphysogobio longidorsalis, R. kumgangensis, Zacco koreanus, Korecobitis rotundicaudata, Iksookimis koreensis, Coreoperca herzi 등 10종이었고, 멸종위기종은 P. tenuicorpus, G. brevibarba, P. phoxinus 등 3종이었고, 천연기념물 Hemibarbus mylodon이 출현하였다. 양식용으로 국외에서 도입된 Onchorhynchus mykiss와 국내 이입종인 Oncorhynchus masou masou가 확인되었다. 우점종인 R. kumgangensis는 모든 조사지점에서 출현하였으며, St. 6을 제외하고 b값이 3.0 이상이고 K값의 기울기가 양의 상관성을 보였다. P. phoxinus는 조사지점 St. 3~St. 6에서 출현하였으며, St. 3과 St. 4에서만 안정적인 개체군 상태를 나타내었다.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.67-67
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• 2003

Dorsal aorta cannulated rainbow trout averaging 505 $\pm$ 6.5g (Mean $\pm$ SD) were divided into 7 groups (5 fish per group). Twenty four hour post feeding, cannulated fish were intubated with one of seven L-amino acid diets containing graded levels of Valine (Val. : 0.45, 0.95, 1.20, 1.45, 1.70, 1.95 or 2.45%) at 1% of body weight. Blood samples were taken at 0, 5 and 24hr after feeding the experimental diets. Post-prandial (5h after feeding) plasma-free Valine concentrations (PPval.) increased linearly from fish fed diets containing Valine between 0.45 and 1.45%, but the concentration remained constant from fish fed diets containing valine between 1.45 and 2.45%. Post-absorptive (24h after feeding) plasma free valine concentrations (PAval) increased linearly from fish fed diets containing valine between 0.45 and 1.45%, but the concentration remained constant from fish fed diets containing valine between 1.45 and 1.95%. Using the broken-line model analysis, the dietary valine requirement by PPval and PAval could be 1.44 and 1.50% in rainbow trout, respectively. These results supported that the estimated dietary valine requirement by PP(val.) and PA(val.) could be in close agreement with the values obtained from the previous conventional feeding method. Thus, the use of PFAA concentrations for determining essential amino acid requirements could be possible in rainbow trout with dorsal aorta cannulation.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.130-138
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• 2016

The use of antibiotics in aquaculture raises environmental and food safety concerns because chronic exposure of an aquatic ecosystem to antibiotics can result in the spread of antibiotic resistance, bioaccumulation of antibiotics in the organisms, and transfer of antibiotics to humans. In an attempt to overcome these problems, high-concentration red clay was applied as an alternative antibiotic against the following common fish pathogens: Aeromonas salmonicida, Vibrio alginolyticus, and Streptococcus equinus. The growth of A. salmonicida and V. alginolyticus was retarded by red clay, whereas that of S. equinus was promoted. Phase contrast and scanning electron microscopy analyses confirmed the attachment of red clay on cell surfaces, resulting in rapid gravitational removal and cell surface damage in both A. salmonicida and V. alginolyticus, but not in S. equinus. Different cell wall properties of grampositive species may explain the unharmed cell surface of S. equinus. Significant levels of oxidative stress were generated in only the former two species, whereas significant changes in membrane permeability were found only in S. equinus, probably because of its physiological adaptation. The bacterial communities in water samples from Oncorhynchus mykiss aquacultures supplemented with red clay showed similar structure and diversity as those from oxytetracycline-treated water. Taken together, the antibiotic effects of high concentrations of red clay in aquaculture can be attributed to gravitational removal, cell surface damage, and oxidative stress production, and suggest that red clay may be used as an alternative for antibiotics in aquaculture.

• 한국어병학회지
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• 제23권1호
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• pp.1-8
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• 2010

무지개 송어 발안란의 이동 이력과 IHNV G gene 염기서열의 계통학적 분석에 의해 IHNV의 국내 이동에 대해서 처음으로 조사되었다. IHNV RtWanju09 분리주는 IHNV RtPy91과 RtJe00의 JRt Shizuoka lineage에 속하는 것으로 나타났으며, 강원도에서 분리된 IHNV RtPy91과 RtWanju09 사이의 G gene의 유전적 차이는 1.77%였고, 약 20년간 우리나라의 JRt Shizuoka lineage에 속하는 한국 분리주들은 최대 3.03%의 유전적 차이를 나타내 계속적으로 바이러스가 진화하는 것을 알 수 있었다. 또한 전라북도 지역에서 분리된 IHNV RtWanju09 분리주는 IHNV가 오염된 강원도 지역산 발안란이 전라북도에 전파되었을 것으로 사료된다.

• 한국수산과학회지
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• 제28권2호
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• pp.131-136
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• 1995

조피볼락, 잉어 및 무지개송어의 혈청을 상온$(15^{\circ}C)$ 저온$(4^{\circ}C)$, 냉동$(-20{\circ}C)$으로 보존하면서 총단백질(TP), 알부민(ALB), 중성지방(TG), 콜레스테롤(CHOL), 포도당(GLC), 인(P), 나트륨(Na), AST 및 ALT의 활성 변화를 상온과 저온에서는 16일까지, 냉동에서는 30일까지 조사하였다. 어종간에 다소의 차이가 있기는 하지만 대체로 단백질 성분인 TP, ALB과 당 성분인 GLC, 무기질인 P, Na의 농도는 안정하였고, 지방 성분인 TG와 CHOL, AST, ALT의 활성은 불안정하였다 그리고 온도에 따른 혈액 성분의 안정성은 상온에서보다는 저온과 냉동에서 대체로 안정하지만, 성분에 따라서는 냉동하여도 매우 불안정한 것이 있다