• 한국어병학회지
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• 제34권2호
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• pp.225-231
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• 2021

In biofloc culture for olive flounder, Paralichthys olivaceus, the possibility of antibiotics treatment was investigated against edwardsiellosis. After inducing edwardsiellosis by immersion in Edwardsiella tarda 1.2 × 10⁵/mL suspension, the survival trends on various biofloc water management and some physiological changes were observed. For biofloc water management, six types of water treatments were carried out, which were no exchange without antibiotics as negative control, the exchange to stored biofloc water, the exchange to stored biofloc water with 20% flow-through, the exchange to fresh biofloc water, half fresh biofloc water and half sea water, and the complete flow-through. There was no significant physicochemical change on water qualities in any type. The exchange to fresh biofloc water was shown the highest survival ratio as 72.3%, and in case of stored biofloc water with 20% flow-through, the survival ratio was also significantly high as 62%. Plasma glucose, cholesterol, total protein, calcium, and magnesium were analyzed as physiological index. Mostly, there was no significant change, but plasma cholesterol showed an initial decrease in low survival group, and an initial increase with high survival group. Consequently, antibiotic treatment against a bacterial disease during biofloc culture is possible as long as the biofloc water management follow along properly.

• 한국수산과학회지
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• 제45권1호
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• pp.35-42
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• 2012

We investigated the effect of dietary supplementation with probiotics on growth performance, feed utilization, innate immunity and disease resistance against Streptococcus iniae in juvenile olive flounder Paralichthys olivaceus. Four experimental diets were made by supplementation with three Bacillus sp. probiotics (B. subtilis, B. pumilus and B. licheniformis) into a basal diet (control) at 0.5% each. Three-hundred fish (average BW, 20 g) were randomly distributed (25 per tank) into twelve 150 L capacity polyvinyl circular tanks with three replicates per dietary treatment. Triplicate groups of fish were fed the experimental diets to apparent satiation (twice per day, 09:00 and 17:00 h) for nine weeks. After the feeding trial, a challenge test was directly conducted against S. iniae. The results indicated that dietary supplementation with the probiotic, Bacillus sp, seemed to improve growth performance of olive flounder. Hematological parameters and innate immunity as determined by nitroblue tetrazolium, myeloperoxidase or superoxide dismutase activities were not significantly affected by the probiotic supplementation. The result from the challenge test suggested that dietary supplementation with probiotics Bacillus sp. can improve the disease resistance of olive flounder against S. iniae.

• 한국수산과학회지
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• 제56권4호
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• pp.532-540
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• 2023

This study aimed to evaluate the effects of dietary supplementation with two different types of hydrolyzed blood meal (HBM) on the growth performance, feed utilization, digestibility and innate immunity of olive flounder Paralichthys olivaceus. A control diet (Con) consisting of 60% fish meal was formulated and four diets containing two different types of HBM at varying concentrations were prepared 2.5 and 5.0% liquid HBM (L2.5 and L5.0) and 0.5 and 1.0% powdered HBM (P0.5 and P1.0). A total of 450 olive flounder (average body weight: 50±0.07 g) were distributed in 15 tanks (240 L), with three replicate groups per diet. The fish were fed the diets to apparent satiation for 9 weeks and subsequently exposed to Edwardsiella tarda. The results showed that fish fed L2.5, L5.0 and P0.5 diets exhibited significantly higher lysozyme activity compared to those fed the Con and P1.0 diets. During the challenge test against E. tarda, the L5.0 and P0.5 fish groups exhibited higher disease resistance than that of the Con group. These findings indicate that dietary supplementation with HBM could positively effect the innate immunity and disease resistance of olive flounder.

• 한국어병학회지
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• 제23권3호
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• pp.369-377
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• 2010

2005년부터 2007년 사이 매분기별로 포항, 울산, 기장, 거제, 완도 지역에서 채집한 양식넙치를 대상으로 기생충, 세균 및 바이러스에 대한 병원체 모니터링 결과를 분석하였다. 총 2,238마리 중 1,528마리(68.3%)에서 병원체가 검출되었다. 연도별 검출률을 비교한 결과, 2005년도에는 60.6%, 2006년도에는 66.7%, 2007년도에는 72.3%의 병원체 검출률을 나타내어 해마다 증가하는 것으로 나타났다. 조사시기별 총 병원체 검출률은 2월에 63.5%, 5월에 67.3%, 8월에 75.1%, 11월에 64.2%로 나타났다. 기생충, 세균 및 바이러스의 검출률은 각각 36.7%, 32.8%, 31.4%로 나타났다. 병원체의 단독감염률 및 혼합감염률은 각각 33.6%와 34.6%로 나타났다. 질병별 분포 조사에서 가장 높은 검출률을 나타낸 병원체는 Trichodina sp. (28.2%), viral nervous necrosis virus (24.3%), Vibrio spp. (11.6%), viral hemorrhagic septicaemia virus (10.5%) 순으로 나타났다.

• 한국어병학회지
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• 제22권3호
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• pp.327-334
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• 2009

본 연구는 넙치, Paralichthys olivaceus에서 Edwardsiella tarda와 Streptococcus iniae에 대한 혼합백신의 효능과 안전성에 대해 조사하고자 하였다. 혼합백신을 주사한 넙치에서 2, 4, 6, 8주 째에 채혈하여 E. tarda와 S. iniae에 대한 항체가 를 microtitre 법으로 조사하였다. 백신 주사 후 3주째에 E. tarda와 S. iniae를 각각 인위감염 시켰을 때 백신구에서 81.0-92.8%의 높은 상대생존율을 보여 혼합백신에 의한 항병력의 증가가 확인되었다. 백신 주사 후 초기에 백신구가 대조구에 비해 체중 증가가 느렸으나 사육기간이 길어지면서 회복되어 대조구와 백신구 체중의 차이를 보이지 않았다. 이 결과는 백신 주사가 넙치의 성장에 영향을 주지 않고 에드와드병과 연쇄구균증을 예방할 수 있음을 보여준다.

• 한국어병학회지
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• 제24권2호
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• pp.47-51
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• 2011

The present study demonstrated lymphocystis disease virus (LCDV) propagation through cytopathic effects (CPE) formation and LCDV detection in olive flounder fin (FFN) cells by polymerase chain reaction (PCR) and fluorescent antibody technique (FAT) methods. Tissue filtrates from the cluster cells produced CPE in FFN cells, which initially cells became enlarged and gradually underwent fusion en masse. Infectivity of culture grown LCDV using the FFN cells reached $10^{2.3}$ $TCID_{50}$/ml at 4 days post infection and the highest titer was measured $10^{6.5}$ $TCID_{50}$/ml at 12 days. The viral DNA was detected in the cell culture supernatants showing CPE and the CPE cells by PCR. Antigen specific strong fluorescence reacting with monoclonal antibody against the virus revealed the presence of viral antigen in the cytoplasm of infected FFN cells. These results suggest that the FFN cell line originated from the olive flounder has a susceptibility of the LCDV.

• Fisheries and Aquatic Sciences
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• 제22권7호
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• pp.14.1-14.8
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• 2019

Olive flounder (Paralichthys olivaceus) is the major species developed for aquaculture in South Korea. Over the long history of olive flounder aquaculture, complex and diverse diseases have been a major problem, negatively impacting industrial production. Vibriosis is a prolific disease which continuously damages olive flounder aquaculture. A bacterial disease survey was performed from January to June 2017 on 20 olive flounder farms on Jeju Island. A total of 1710 fish were sampled, and bacteria from the external and internal organs of 560 fish were collected. Bacterial strains were identified using 16 s rRNA sequencing. Twenty-seven species and 184 strains of Vibrio were isolated during this survey, and phylogenetic analysis was performed. Bacterial isolates were investigated for the distribution of pathogenic and non-pathogenic species, as well as bacterial presence in tested organs was characterized. V. gigantis and V. scophthalmi were the dominant non-pathogenic and pathogenic strains isolated during this survey, respectively. This study provides data on specific Vibrio spp. isolated from cultured olive flounder in an effort to provide direction for future research and inform aquaculture management practices.

• 한국미생물·생명공학회지
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• 제50권3호
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• pp.347-353
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• 2022

본 연구는 기존의 probiotics로서의 안전성을 입증한 B. cabrialesii sp. K1과 prebiotics 중 inulin 3%와 혼합하여 synbiotics로서의 넙치의 성장과 비특이적 면역 반응 및 세균성 감염에 따른 폐사에 미치는 영향을 검토하였다. 8주 동안 단일 프로바이오틱스 B. cabrialesii sp. K1과 inulin 3% 를 혼합한 신바이오틱스를 급이 한 결과 성장에서는 유의적인 차이를 보이지 않았다. 혈액학적 검사의 경우 AST, total protein 및 cholesterol에서 유의적인 차이를 보였고 ALT와 glucose는 유의적인 차이가 없었다. 비특이적 면역반응에서는 유산균 첨가 또는 주사제로 인한 라이소자임 활성이 유익 하다고 알려져 있으나 본 연구에서는 8주동안 대조구와 비교시 유의적 차이가 없었다. 또한 B. cabrialesii K1의 경우 단일 프로바이오틱스구보다 신바이오틱스구가 대조구에 비해 NBT 활성이 증가된 것을 확인할 수 있었다. 다음 넙치의 사이토카인 발현을 확인한 결과 B. cabrialesii sp. K1를 단일 (probiotics구)로 사용했을 경우 대조구와 비교 시 비장에서 유의적으로 낮게 발현되었으나 synbiotics구의 경우 비장에서 발현이 유의하게 증가되었다. 그러나 나머지 간과 장, 신장에서는 세 개의 그룹 간의 유의적 차이를 나타내지 않았다. 마지막으로 2주동안의 인위 감염을 검토한 결과 대조구는 E. tarda 95%, S. parauberis 85%, S. iniae 85%로 각 각의 폐사율을 나타냈다. Probiotics구는 E. tarda 85%, S. parauberis 80%, S. iniae 80%의 폐사율을 보였고, synbiotics 구는 E. tarda 80%, S. parauberis 80%, S. iniae 85%로 각 각 나타났다.

• Fisheries and Aquatic Sciences
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• 제18권4호
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• pp.367-372
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• 2015

We investigated the effects of dietary supplementation of two types (powder or liquid) of propolis on innate immunity and disease resistance of olive flounder Paralichthys olivaceus against Edwerdsiella tarda. A total of 600 fish averaging 30 g were randomly distributed into 24 tanks in groups of 25. Three tanks were assigned to each of eight experimental diets: 0 (Control), 0.25, 0.5, 0.75 and 1 % propolis in powder form and 0.25, 0.5 and 1 % propolis in liquid form (PP0.25, PP0.5, PP0.75, PP1, LP0.25, LP0.5 and LP1, respectively). Fish were fed each experimental diet twice daily for four weeks to apparent satiation. At the end of the feeding trial, lysozyme and myeloperoxidase activities and total immunoglobulin level were significantly higher in fish fed the PP1 and LP0.5 diets compared to those fed the control diet. The PP1 diet was also associated with a significant increase in anti-protease activity compared to the control diet. After challenge with E. tarda, fish fed the LP0.5 diet showed numerically higher survival compared to the other groups. This study indicates that non-specific immune responses of olive flounder can be enhanced by dietary supplementation with powder and liquid forms of propolis, and that the optimal level would be 1% in powder form or 0.5% in liquid form. It seemed that growth performance and feed utilization are not affected by the propolis supplementation in diets for olive flounder.

• 한국수산과학회지
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• 제48권3호
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• pp.337-345
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• 2015

To investigate the causes of emaciation in cultured olive flounder Paralichthys olivaceus in Korea. We performed histological examinations and polymerase chain reaction (PCR) with a new primer set. In most cases, the most severe emaciation was observed in the abdominal area Using PCR on extracted livers, kidneys, spleens, gills, brains, and intestines, we found that areas around the kidneys and intestines were as almost always positive. In significantly emaciated fish, PCR was positive in all internal organs except the gills. In addition, the homology of 812-bp nucleotide sequences of the 28S rRNA gene was more than 99% in emaciated fish. Partial homology with Myxobolus spp. and Cystodiscus axonis, whose data were obtained from GenBank was 86% and 88%, respectively. Histological examinations detected spores in kidneys and intestines but not in other organs. We also performed cohabitation experiments to determine whether infections could be exchanged among species or only within species. Uninfected olive flounder and red sea bream, Pagrus major, cohabitating with emaciated olive flounder showed 100% and 0% cumulative mortality, respectively. Thus the cause of emaciation in cultured olive flounder of Korea is likely due to a new parasite.