• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.239-244
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• 2021

In the present study, liquid chromatography tandem-mass spectrometry was used to conduct a risk assessment of ethoxyquin and ethoxyquin dimer residues in 288 farmed fish sold in wholesale and traditional markets in Seoul. The detection range (detection rate) of ethoxyquin and ethoxyquin dimer was 0.005~0.309 mg/kg (4.9%) and 0.001~2.828 mg/kg (69.8%), respectively. Ethoxyquin was detected only in freshwater eels, loaches, catfish, and flatfish, whereas ethoxyquin dimer was present in all fish species. To estimate the dietary exposure levels of ethoxyquin and ethoxyquin dimer, the hazard index, calculated using the acceptable daily intake and estimated daily intake, ranged from 0.001 to 0.300%. Our results indicate that there is no significant exposure risk to humans from these farmed fish despite 10 farmed fish samples exceeding the maximum residue level (1.0 mg/kg as the sum of ethoxyquin and ethoxyquin dimer).

• Food Science and Preservation
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• v.30 no.3
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• pp.459-471
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• 2023

The Bayesian network (BN) model was applied to analyze the characteristic variables that affect compliance with safety inspections of farmed eel during the production stage, using the data from 30,063 cases of eel aquafarm safety inspection in the Integrated Food Safety Information Network (IFSIN) from 2012 to 2021. The dataset for establishing the BN model included 77 non-conforming cases. Relevant HACCP data, geographic information about the aquafarms, and environmental data were collected and mapped to the IFSIN data to derive explanatory variables for nonconformity. Aquafarm HACCP certification, detection history of harmful substances during the last 5 y, history of nonconformity during the last 5 y, and the suitability of the aquatic environment as determined by the levels of total coliform bacteria and total organic carbon were selected as the explanatory variables. The highest achievable eel aquafarm noncompliance rate by manipulating the derived explanatory variables was 24.5%, which was 94 times higher than the overall farmed eel noncompliance rate reported in IFSIN between 2017 and 2021. The established BN model was validated using the IFSIN eel aquafarm inspection results conducted between January and August 2022. The noncompliance rate in the validation set was 0.22% (15 nonconformances out of 6,785 cases). The precision of BN model prediction was 0.1579, which was 71.4 times higher than the non-compliance rate of the validation set.

• Korean Journal of Veterinary Service
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• v.29 no.2
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• pp.103-110
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• 2006

Ticks cause economic losses to the deer industry by decreasing the growth and production of the farmed animals. The mediation of ticks affects humans and animals by causing contagious disease both directly and indirectly. Blood from farmed deer from the areas near Jangsu branch was collected for screening of infectious protozoa and rickettsial disease. Seventy deer blood samples were collected from 30 different deer farms located in Jinan, Jangsu and Muju. This blood samples were used for blood slide smear examination and hematological analysis. DNA from these samples was extracted and was used for PCR analysis for detection of gene fragments of Theileria spp, Babesia spp, Anaplasma spp and Ehrlichia spp. In the blood slide smear examination and PCR analysis all samples did not show presence of protozoal and rickettsial diseases. Eight blood samples showed anemia, 1 sample showed iron deficiency and 7 samples showed regenerative anemia. Results for PCR analysis showed 2 samples were positive for T orientalis. All DNA samples were negative for Babesia spp, Anaplasma spp, and Ehrlichia spp.

• Korean Journal of Ichthyology
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• v.29 no.1
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• pp.75-79
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• 2017

About 10% mortality occurred in cultured rainbow trout Oncorhynchus mykiss at a marine farm in Jeju in 2014. Diseased fish showed markedly abdominal distension and distended stomach. Although parasites, bacteria or viruses were not isolated from diseased fish, numerous Candida sp. were isolated from distended stomach. In experimental infection with Candida sp., mortality was not observed in most fish and clinical sign of distended stomach was not observed in the fish. These results suggest that Candida sp. may not be the etiologic agent of stomach distension syndrome. This is the first report of stomach distension syndrome in seawater farmed rainbow trout in Korea.

• Korean Journal of Veterinary Service
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• v.22 no.2
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• pp.113-119
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• 1999

The most common cause of death is ostrich chick fading syndrome(OCFS), which is due to bacterial infection during artificial incubation and hatching. Six farmed ostrich chicks aged 3 and 10 days in Chonbuk province, were submitted to Chonbuk Livestock Development and Research Institute for necropsy, Clinically, birds showed hair loss, ocular exudate, lethargy, diarrhea, and subsequently died 3-5 days after onset of clinical signs. Grossly, umbilicus was enlarged. White-yellowish purulent nodules were scattered on the lung and the membrane of air-sac was thickened and had inflamed exudate on the surface in two chicks that died 3 days after hatching. In 10 days-old chick, intestine was shown rodding segmentally. Yolk sac was still retarded and its surface was partially hemorrahgic. The synovial fluid of the leg was yellowish. Microscopically, multifocal purulent exudates were scattered on the lung. Capillary microthrombi in the glomerulus were prominent and tubular epithelia were necrotic. Necrotic hepatocytes were scattered and intestine were congested. Microbiologically, Pseudomonas sp and/or E coli were isolated from air-sac, lung and/or liver. This case suggests that poor hygiene during artificial incubation, hatching or in the first week after hatching may cause high mortality of the ostrich chicks.

• Journal of fish pathology
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• v.15 no.1
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• pp.1-7
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• 2002

On April of 2000 and February of 2001, a disease characterized by darkening, ascites and enlargement of the spleen occurred in flounder, Paralichthys olivaceus, farmed near northern and eastern coasts of Korea. Various degree of necrosis including liquefactive-type was observed mainly in hemopoietic tissue of spleen and kindney. Certain tissue such as branchial soft tissue including epithelium showed a similar necrotic findings. But some tissues such as intentine had several necrotic clusters of wandering cells, being possibly leukocytes. Necrotic evidences of blood cells were evident in various tissues including hemopoietic tissues. Necrobiotic bodies were frequently encountered in blood smear preparations. Bullet type-virious were detected in the spleenic cells. Each virion was about 500 nm in diameter and 170nm in length. From these results, this disease was thought to be a rhabdoviral disease.

• Animal cells and systems
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• v.16 no.1
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• pp.41-49
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• 2012

Eighteen new polymorphic microsatellite markers were developed for the Korean mi-iuy croaker ($Miichthys$ $miiuy$, Perciformes, Sciaenidae), and allelic variability was compared between a wild population in Mokpo, Korea, and a hatchery population in Tongyeong, Korea. All loci were amplified readily and demonstrated allelic variability, with the number of alleles ranging from 5 to 37 in the wild population, and from 4 to 12 in the farmed population. The average observed and expected heterozygosities were estimated, respectively, to be 0.74 and 0.78 in the hatchery population samples, and 0.79 and 0.86 in the wild samples. These results indicate lower genetic variability in the hatchery population compared with the wild population, and significant genetic differentiation between the wild population and the hatchery samples ($F_{ST}$=0.058, P<0.001). These microsatellite loci may be valuable for future population genetic studies, monitoring changes in the genetic variation within stocks in a commercial breeding program, conservation genetics, and molecular assisted selective breeding of the mi-iuy croaker in the future.

• 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.

• Journal of fish pathology
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• v.31 no.2
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• pp.123-129
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• 2018

Parvicapsula anisocaudata, a myxosporean parasite, is presumably one of causative agents of emaciation in olive flounder Paralichthys olivaceus in Korea. In this study, we report a case of unusual abdominal distension due to exceptionally enlarged liver in farmed olive flounder. For the identification of the causative agent, bacteria and nucleic acids of virus that are possibly present were attempted to isolate from internal organs of five fish sampled from a fish farm in Jeju. Although a few bacterial colonies were isolated from some samples, there was no evidence that fish were primarily affected by virus and/or bacteria. From histopathological analysis, myxosporean were found in almost all internal organs, particularly in the stomach. The causative agent was identified as P. anisocaudata by sequencing a part of small subunit rRNA. This study contains a very unusual case of olive flounder heavily and systemically infected with P. anisocaudata, showing excessively enlarged liver with a small amount of ascitic fluid.

• Fisheries and Aquatic Sciences
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• v.26 no.10
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• pp.605-616
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• 2023

Scuticociliatosis, caused by the parasitic pathogen Miamiensis avidus, poses a significant threat to olive flounder farms in South Korea. Infected fish suffer from severe systemic infections affecting various organs, with potential secondary bacterial diseases. This study investigated the emergence of different M. avidus serotypes in 20 olive flounder farms on Jeju island, South Korea, from 2015 to 2020. Additionally, we identified Tenacibaculum maritimum as a co-infecting bacteria. Based on serotyping and monitoring data, we developed a trivalent vaccine targeting two serotypes of M. avidus and one strain of T. maritimum. The efficacy of the vaccine was evaluated under laboratory conditions and demonstrated a relative percentage of survival (RPS) of 75%, 80%, and 93% for M. avidus serotype I, M. avidus serotype II and T. maritimum, respectively. Furthermore, successful field trials conducted on four different olive flounder farms resulted in significantly higher survival rates (52%-76% RPS) and weight gains in vaccinated fish. Overall, this study presents an effective vaccine against M. avidus and T. maritimum infections in farmed olive flounder, making a valuable contribution to sustainable aquaculture in South Korea.