• Journal of fish pathology
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• v.33 no.1
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• pp.97-101
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• 2020

Although aquaculture production rates grown over the years, aquatic animal diseases occur every year which causes substantial economic losses. When an aquatic animal is infected with an aquatic animal pathogen it is either incinerated or buried according to the aquatic life disease control act. Although these methods prevent the spread of disease, it is not environment friendly. Here, we developed an aquatic animal rendering equipment for disposal of fish waste which is environment-friendly and efficient. Also, fertilizer components of fish waste were evaluated value for recycling. The mobile rendering equipment was designed for field operation and/or high temperature and pressure system, oil and water separator, and shredding drying apparatus. During the experiment (July-2016 to November-2016), a total of 53,824 kg fish waste was collected, and 29,216 kg compost of rendering by-product was made. Also, compost made from viral (Viral hemorrhagic septicemia virus) infected fish did not reflect any detectable pathogen. The concentration of nitrogen, phosphorus, and organic matter in the fish waste compost were 2.17%, 26.98%, and 92.44%, respectively. The results suggest that fish waste used in this study was decomposed efficiently as per the official standard for fertilizer product. This equipment can be useful for efficient inactivation of the aquatic animal pathogenic agents and recycling of the fish waste in an environment-friendly manner.

• Journal of Veterinary Clinics
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• v.26 no.3
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• pp.306-310
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• 2009

Mass mortality was occurred in adult koi carp(Cyprinus carpio) at a private pond near Samchunpo city in the early November, 2007. Its water temperature was $11^{\circ}C$ and turbidity was very high. The fishes diseased were shown widely distributed hemorrhages, deep ulcerations on the whole body surface and severe erosions in the all fins. In necropsy, excess ascitic fluid was observed and spleen and kidney affected were enlarged. In microscopic observation, it was examined widely distributed severe dermal ulceration, multifocal gill lamella hyperplasia, severe fibrinous pericarditis, multifocal nephritis and hepatitis. The bacteria suspected were isolated using tryptone soya agar and identified as motile Aeromonas hydrophila as results of biochemical tests using API 20E and 20NE. According to previous reports, A. hydrophila infection were mainly occurred in fingerling at high temperature. However, this case exhibited that A. hydrophila infection can develop on adult koi carp even in the winter season.

• Korean Journal of Veterinary Research
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• v.50 no.1
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• pp.29-35
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• 2010

Yersinia (Y.) ruckeri has been recognized as a serious bacterial pathogen to several kinds of fish, including rainbow trout. However, there are no reports about the characteristics and pathogenicity of Y. ruckeri isolated from farm-cultured eels. In this study, we isolated and characterized Y. ruckeri from the farm-cultured eel Anguilla japonica in Korea. We investigated the phenotypic and genotypic characteristics of Y. ruckeri and tested the virulence of Y. ruckeri isolates on experimentally infected eels. Examination of the flagellar morphology of Y. ruckeri by electron microscopy showed peritrichous flagella in its cell body. Biochemical reaction studies showed overall identical profiles between the isolates and the reference strain of Y. ruckeri in API 20E and API ZYM tests. We sequenced the 16S rRNA of the Y. ruckeri (1,505 bp) for the genotypic characterization (National Center for Biotechnology Information accession number EU401667). Comparison of the 16S rRNA sequences with previously reported Y. ruckeri strains revealed similar phylogenetic relationships. In the virulence assay of the Y. ruckeri on eels, the eels exhibited listlessness, but Y. ruckeri was reisolated from those of the gills and kidneys.

• Korean Journal of Veterinary Research
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• v.50 no.4
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• pp.331-333
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• 2010

Moribund albino catfish, Clarias sp., displayed from an indoor private commercial aquarium were submitted in the laboratory for diagnostic examination. Dense culture of bacteria was recovered from the kidney and was characterized using Vitek System 2 and showed 98% probability to Aeromonas (A.) hydrophila. PCR result showed positive using A. hydrophila extracellular hemolysin gene ahh1 (130 bp) and aerolysin gene aerA (309 bp). The 16S rRNA gene was identical and exhibited 97% sequence similarity with the other known isolates of A. hydrophila available in the GenBank. In this paper, we reported the isolation and molecular detection of A. hydrophila from an albino catfish.

• Journal of Fisheries and Marine Sciences Education
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• v.16 no.2
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• pp.218-226
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• 2004

During the last two decades, the rapid increase in aquaculture world wide, particularly in finfish and shellfish culture, is the result of both area expansion and production intensification. Under these conditions, the prevalence and spread of infectious diseases have increased as a result of higher infection pressure and decreased resistance of the aquatic animals. Accordingly, the effective control of infectious diseases has become more and more important to development of aquaculture. Recently the Pathology Team of National Fisheries Research and Development(NFRDI), has played pivotal roles in establishing the national management and control system of aquatic animal health and disease by new legislative works and technical guidelines. Under the national aquatic animal disease control framework, the Pathology Team of NFRDI and MOMAF(Ministry of Maritime Affairs and Fisheries) should also establish effective management and regulations, with the support of enforcement and monitoring policies. In conjunction with effective aquatic disease national management, financial assistance or alternative compensation options for aquaculture should also be available in the event of production losses or eradication system.

• Journal of fish pathology
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• v.23 no.1
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• pp.99-106
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• 2010

Aquatic animal diseases control act which is to assure the prevention of outbreak and spread of aquatic animal diseases in Korea has come into effect since 22 December 2008. In order to prevent outbreak and spread of aquatic animal diseases, risk analysis is newly introduced. The introduction of risk analysis for movement of aquatic animals related to implementation of recommendation of the World Trade Organization (WTO) Agreement on the Application of Sanitary and Phytosanitary Measures and should be conducted in accordance with guidelines of OIE Aquatic Animal Health Code. This report involves gathering and analysing the information of international regulation and situations of risk analysis framework in Korea for movement of aquatic animals.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.307-309
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• 2008

The metacercariae species have often been isolated from fresh water fish in Korea. In this study, we reported Clinostomum complanatum, a species of metacercariae isolated from gill and muscle of Korean barbel (Hemibarbus mylodon), a natural monument fresh water fish in Korea, by morphological observation. The excysted metacercariae, tongue-shaped and progenetic, were 3.11-4.62 mm in length and 0.90-1.43 mm in width. Fresh water fishes are known as the second intermediate hosts of C. complanatum. This is the first isolation report from Korean barbel.

• Journal of fish pathology
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• v.32 no.1
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• pp.37-43
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• 2019

Due to the rapid global expansion of aquaculture industry during the past decades, production volume of aquatic organisms has accordingly grown. This has been accompanied by a rise in the incidence of diseases in aquatic organisms, leading to an increased use of aquatic medicines. While aquatic medicines are essential for the prevention and treatment of diseases of aquatic organisms, misuse can cause evolution of antibiotic-resistant bacteria and pose serious problems to the safety and hygiene of fisheries products. In this study, we surveyed and compared, by analyzing data compiled by all national control centers for aquatic animal diseases in South Korea, to estimate the amount of aquatic medicines sold in different regions between 2012 through 2015. Since we also examined the marketing routes of aquatic medicines, this basic data can be utilized for policy implementation to improve drug safety. In the future research, however, it will be clearly necessary to estimate directly the amounts of drugs actually applied to aquaculture organisms. The current sales figure data should be helpful for preparation of an effective system for aquatic drug use management.

• Journal of fish pathology
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• v.27 no.1
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• pp.67-75
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• 2014

Aquaculture drugs have used to prevent disease in aquaculture field for many years. In spite of many advantages, overdose and abuse may cause environmental pollutions and antibiotic resistances. Many countries try to protect the environment, biospecies and food safety. Recently, Korea enact laws and ordinances such as the Aquatic Animal Disease Control Act. The purpose of this act to contribute to the stable production and control system for aquatic diseases. The Maximum residue limits (MRLs) of aquaculture drugs have been established by Ministry of Food and Drug Safety (MFDS) and Drug licensing was in National Fisheries Research and Development Institute (NFRDI) by Aquatic Animal Disease Control Act. There is 750 items in aquaculture drugs and these are classified into 4 group, which is approval, necessary for prescription, unregulated and safety drug, and banned drug. MRLs of 30 items in aquaculture drug have been established by Food Sanitation Act. Future research is required to determine the suitable for abundant varied fishes of drugs for side effects and safety.

• Fisheries and Aquatic Sciences
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• v.23 no.8
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• pp.20.1-20.18
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• 2020

Background: Olive flounder, Paralichthys olivaceus, is an economically important aquaculture species in Korea. Olive flounders have been heavily damaged by streptococcal infections every year and are treated with antibiotics. However, antibiotic abuse is causing the emergence of resistant strains, and to overcome this, research has shown that new antibiotics must be applied. Tylosin is a relatively safe antibiotic and has good activity against Gram-positive bacteria and mycoplasma. We studied the therapeutic effects and side effects of tylosin on Streptococcus parauberis-infected olive flounder. Methods: After artificial infection of olive flounder with S. parauberis SPOF18J3, an appropriate dose of tylosin was confirmed by intramuscular injection (I.M.) at 2.5, 5, 10, and 15 mg/kg, and oral administration at 10 and 20 mg/kg. After I.M. and oral administration dosing of tylosin, side effects were confirmed by serological analysis, histopathological analysis, and median lethal dose (LD₅₀) analysis at both an appropriate concentration and a high concentration. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey's test (p < 0.05). Results: The appropriate I.M. and oral administration concentration of tylosin administered to olive flounder infected with S. parauberis SPOF18J3 was found to be 10 mg/kg. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were showed not significantly different between the control group and the experimental groups. The histopathologic results showed mild inflammatory responses in muscle and tubular vacuolization and tubular atrophy appeared, but there were no significant differences between the groups. The LD₅₀ was confirmed to be 461 mg/kg. Conclusion: In this study, an effective treatment method was provided by verifying the treatment effects and side effects of tylosin in olive flounder infected with S. parauberis, which can be applied directly to aquaculture sites. In addition, these results may be used as a reference for evaluation required upon request to obtain approval for tylosin antibiotics as fishery antibiotics in Korea. After approval, it is possible that a fishery disease manager will be able to prescribe and sell the antibiotic tylosin.