• 한국수산과학회지
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• 제39권6호
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• pp.466-471
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• 2006

We investigated the changes in body weight (BW), plasma sex steroid hormone profiles, and testicular development of cultured male eel Anguilla japonica during an artificial maturation process. Eels that received weekly intraperitoneal injections of eel's ringer solution containing human chronic gonadotropin (HCG) were examined. In the ringer-treated control, BW changes decreased slowly during the experimental period. Plasma testosterone (T), 11-ketotestosterone (11-KT) and $17{\alpha},\;20{\beta}$-dihydroxy-4-pregnen-3-one (DHP) levels In the control remained low and did not show significant changes. Moreover, all germ cells in the testes of the control were spermatogonia. In the HCG-treated male eels, however, BW changes increased gradually from the fifth week and then decreased slowly. The plasma T level increased rapidly (p<0.05) in the second week and then decreased slowly. The plasma 11-KT level increased dramatically (p<0.05) in the second week and was maintained until the end of the experiment. The plasma DHP level increased progressively from the second week and peaked in the eighth week (p<0.05). The testes of HCG-treated male eels were more developed than those of the control; most were at the spermatozoa and spermatid stages and showed active spermiation. Thus, spermatogenesis and spermiation in the cultured eel can be induced by repeated injections of HCG.

• 한국어병학회지
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• 제15권2호
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• pp.49-56
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• 2002

Effects of Temperature on the Pharmacokinetics of norfloxecin (NFX) were studied in the cultured carp,Cyprinus carpio, and cel, Anguilla japonica, using high performance liquid chromatography (HPLC) originally developed for quinolone determination in livesrocks. Pharmacokinetics of NFX was apparently affected by ambiem water temperature. In a two-compaament model for carp after oral dosage of 20 mg/K01 at $13^{\circ}C$ and $23^{\circ}C$ and 5.20/hr, respectively. In carp the $K_{\iota\nu}$, $T_{max}$and $C_{max}$ for carp at $13^{\circ}C$ were 13.30/hr, 17.44 ${\mu}g$/$m\ell$ and 7.00 ${\mu}g$/$m\ell$, respectively. The" correspoeding values at $23^{\circ}C$ were 3.93/hr, 15.40 ${\mu}g$/$m\ell$ and 9.44 ${\mu}g$/$m\ell$, respectively. The AUC and T were 355.66 ${\mu}g$ hr/$m\ell$, and 12.70 hr at $13^{\circ}C$ and 417,24 ${\mu}g$ hr/$m\ell$ and 13.86 hrs at $23^{\circ}C$, respectively. Similar trends were revealed in the NFX pharmacokinetics of eel kept under the two water temperature regimes aftee oral NFX dosage of 20 mg/kg. These pharmacokinetkal results have some implication in the optimal usage of recently introduced antibacterials in farmed fish, which were originally adapted for poultry and mammalian species.

• 한국어병학회지
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• 제22권3호
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• pp.367-374
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• 2009

오매 추출물 첨가 사료의 투여가 양식 뱀장어의 비특이적 면역 반응에 미치는 효과를 조사하였다. 그 결과, 뱀장어의 혈청 내 lysozyme의 활성을 증가시키는 것으로 나타났고, 점액 내 lysozyme 및 혈청의 살균능에 있어서는 차이를 나타내지 않았다. 혈청 내 lysozyme의 활성은 추출물 첨가 사료 투여 후 2주째에 증가하기 시작하여 5주째에 가장 높은 것으로 나타났다. 어류 병원성 세균인 Edwardsiella tarda와 Aeromonas hydrophila 균에 대한 저항성 실험에 서 오매 추출물 첨가 사료을 투여한 실험구가 대조구에 비해 세균에 대한 저항성이 높게 나타났다. 또한 오매 추출물 첨가 사료를 투여한 실험구에서 대조구에 비해 성장이 좋게 나타났다.

• 수산해양교육연구
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• 제28권6호
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• pp.1573-1580
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• 2016

The disease occurred in cultured eel (Anguilla japonica) in a recirculatory culture system without any separated filtration apparatus. As the pond had a high level of nitrite with $60mg/{\ell}$, 1% NaCl was added to reduce nitrite toxicity to eel. The first outbreak was observed a week after the NaCl treatment and continued for 10 days. Accumulated mortality was about 0.2-0.5%. Affected fish ranged from 150-350 g were usually anorexic and exhibited yellow colour in the skin of the abdominal region and at the base of pectoral fins, as well as in the eyes. In a few individuals with severe symptoms, the lateral skin was also yellowish. The spleen, kidney, muscle and gall bladder were yellowish and the liver was pale-yellow colour but green on the posterior part. The gall bladder was shrunken without bile. Some abnormal erythrocytes such as "tear drop" cells (dacrocyte) were observed in peripheral blood smears stained with May-Grunwald Giemsa. Hematocrit values and hemoglobin contents in the jaundiced eel were significantly lower compared with apparently heathy eel. Severe haemosiderosis accompanied by erythrophagocytosis was found in the kidney and spleen. Haemosiderin deposits were observed in macrophages of the haematopoietic tissue of the kidney and in the splenocytes. But no significant alterations were found in the hepatic cells. In this study we report the first outbreak of jaundice in cultured eel in Korea. Pathological and hematological investigations suggested that severe hemolysis may resulted in jaundice in eel although the cause of hemolytic jaundice was not identified in this study.

• 한국어병학회지
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• 제25권3호
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• pp.173-180
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• 2012

비브리오 감염증 (Vibriosis) 은 해산어에서 흔히 발생하는 세균성 감염증으로 어종에 따라 다양한 종이 분리, 발견되어지고 있다. 본 보고에서 병어로부터 TCBS한천배지에서 노란색 colony를 생성하는 비브리오속 세균이 분리되었고, 16S rRNA염기서열분석을 통하여 Vibrio scophthalmi로 확인하였다. 병어의 주요 증상으로 체표 출혈, 복강 내벽 출혈, 심한 장염, 복수 저류가 나타났다. 병리조직학적 관찰을 통하여 비장과 신장의 괴사, 장내 상피조직의 괴사, 탈락, 장의 상피하층인 점막고유층에서의 충, 출혈이 관찰되었다. 본 보고는 극동산 양식뱀장어에서의 V. scophthalmi 감염증례에 대한 첫 보고이다.

• 한국수산과학회지
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• 제54권4호
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• pp.418-425
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• 2021

The effects of an aquaponic system based on biofloc technology (BFT-AP) were analyzed for eel Anguilla japonica as aquaculture species and caipira Lactuca sativa as the cultivated crops. The rate of weight gain rate by the eels was 178% (BFT-AP 200 head) > 136% (BFT-AP 100 head) > 100% (BFT). The eel body weight in the BFT-AP (200 head) significantly increased when compared to the BFT only eel group (P<0.05). The weight of the upper layer of caipira was 91±8.5 g (200 head) > 90±8.9 g (100 head) > 48±8.3 g (Hydroponic crop, HP). The crop growth in all BFT-AP groups was higher than the control, the hydroponic group. The total ammonia nitrogen (TAN) and NO₂^--N concentrations decreased in the BFT-AP group when compared to the BFT group. It was possible to remove nitric acid from the aquaponics system and reuse it as eel rearing water. Although some nutrient concentrations were low in BFT when compared to HP, the nutrient concentration was sufficient for plant growth. The results show that BFT has the potentially to provide a sustainable aquaponic system.

• 한국어병학회지
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• 제33권2호
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• pp.153-161
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• 2020

Cytochrome P450(CYP) gene is involved in the biotransformation of drugs and environmental pollutants. In this study, we analyzed the nucleotide sequence of the Anguilla japonica CYP1(AjCYP1) family gene and examined the relative expression of AjCYP1A, AjCYP1B and AjCYP1C1 in response to the exposure to environmental pollutants. After exposure to B[a]P 20mg/kg bw, the expression of AjCYP1 family gene increased over time. Among four tissues examined (liver, spleen, gill and kidney), AjCYP1 family gene was expressed significantly in the kidney. Compared with the control group, AjCYP1A was expressed about 5-fold at 48 hr, AjCYP1B about 6-fold at 24 hr, and AjCYP1C1 about 4-fold at 24 hr. However, after exposure to B[a]P 200mg/kg bw, AjCYP1A did not change in all tissues. On the other hand, AjCYP1B was expressed at about 4-fold at 24 hr in the spleen and 4-fold at 48 hr in the gill. Finally AjCYP1C1 was expressed 3.7-fold and 4.3-fold in the spleen and kidneys at 48 hr, respectively. Taken together, our results suggest that the expression of AjCYP1 gene in eel tissues might be used as a useful tool to assess the exposure to environmental pollutants in aquaculture system.

• 한국어류학회지
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• 제27권4호
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• pp.263-274
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• 2015

2014년 9월부터 12월까지 국내에 서식하는 뱀장어 Anguilla japonica 총 182개체를 silvering index에 따라 4개의 단계로 구분하고, 성숙에 따른 형태 및 생물학적 특성 변화를 조사하였다. 하천 및 하구에서 채집한 개체군 (34.6%)은 댐 호 (3.8%)에서 채집한 개체군에 비하여 성숙뱀장어의 비율이 높았다. 성비 (♂/♀)는 0.11 (n=182)로 암컷의 비율이 매우 높았다. 성숙뱀장어 단계로 진행될수록 전장은 커지고, 체중은 증가하였다. 단계별 계측형질 비교에서 전장에 대한 두장 및 가슴지느러미 길이 백분비, 두장에 대한 가로 및 세로 안경의 백분비에서 각각 통계적으로 차이를 보였으나, 전장에 대한 등지느러미 및 뒷지느러미 기점거리에서는 통계적으로 차이를 보이지 않았다. 생식소성숙도지수 (Gonado-somatic index, GSI), 비만도지수 (Condition factor, K), 소화관지수 (Gut index, GI), 안경지수 (Eye index, EI) 및 간 중량지수 (Hepato-somatic index, HSI) 중 GSI는 4가지 단계를 모두 구분할 수 있는 형질이었다. 한편 외부 체색 및 형태는 성숙한 A. japonica인 S2로 보이지만, 나머지 대부분의 단계별 분류 형질에서는 미성숙뱀장어인 Y1과 Y2에 해당하는 pseudo-silver eel 한 개체가 채집되어 이에 대한 형질을 비교하였다.

• 한국수산과학회지
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• 제42권2호
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• pp.104-108
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• 2009

Glycation and oxidation induce formation of carbonyl (CO) groups in proteins, which can be used to develop an index of cellular aging. Methyl glyoxal (MG) and hypochlorite anions are deleterious products of oxygen free-radical reaction. The effects of eel carnosine on protein modification mediated by MG and hypochlorite were studied. MG and hypochlorite induced formation of carbonyl groups with high molecular weight and cross-linked forms of ovalbumin. The presence of eel carnosine effectively inhibited these modifications in a concentration-dependent manner. Imidazole ring in eel carnosine might have a primary role in inhibition of protein glycation. Our data suggests that the eel carnosine may be useful as a "natural" anti-glycating agents.

• Fisheries and Aquatic Sciences
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• 제18권4호
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• pp.387-393
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• 2015

Biotyping of Vibrio vulnificus strains isolated from marine environments along the south coast of Korea showed that the majority of the isolates (94.7%) belonged to biotype 1 and the remaining isolates (5.3%) belonged to biotype 2. Analysis of 16S rRNA V. vulnificus strains isolated from marine environments using a multiplex polymerase chain reaction (PCR) revealed that 78.7% were type A and 21.3% were type B. Random amplified polymorphic DNA (RAPD) was used to analyze the genomic differences in V. vulnificus among the biotype 2 strains isolated from marine environments (newly isolated strains group) and reference strains obtained from infected eels (reference strains group). The two groups had distinctly different profiles of the amplicons produced from RAPD. Additionally, biochemical comparison of these strains revealed that all four strains isolated from marine environments differed from the strains isolated from eels in their ability to promote D-mannitol fermentation. Two (NH 1 and NH 2) out of four isolates of biotype 2 from marine environments showed pathogenicity in eels Anguilla japonica in a challenge test. These isolates did not agglutinate with antisera against V. vulnificus NCIMB 2137 (serovar E), ATCC 27562 (non-serovar E), and ATCC 33816 (atypical serovar E).