• Animal cells and systems
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• 제1권4호
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• pp.549-552
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• 1997

A new species of Korean ophichthid eel, Ophichthus rotundus, is described on the basis of specimens collected from Kyehwado, Chollabuk-do, Korea. 0, rotundus is characterized by small eye, elongated and slender body, short head and trunk, small eye, long tail, low dorsal and anal fins, many vertebrae, and no spotted pattern on body and fins.

• 한국발생생물학회지:발생과생식
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• 제22권3호
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• pp.289-295
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• 2018

Large quantity of eggs fail to be fertilized and many of fertilized eggs are unable to hatch in the eel, Anguilla japonica. Larvae of eel absorb egg yolk up to 8 days after hatching but the majority of hatched larvae die before they reach the stage of first feeding in this species. Genes of key enzymes for yolk processing (cathepsin B, D, L and lipoprotein lipase - abbreviated as ctsb, ctsd, ctsl and lpl, respectively) could be associated with egg quality. In this study, we investigated differences in the expression of these genes between floating eggs and sinking eggs, and also the relationship between the gene expressions of the enzymes and fertilization rates in the fertilized eggs obtained from artificially matured female eels. Expressions of yolk processing enzyme genes did not show significant difference between floating and sinking egg groups. Expression of ctsb decreased when fertilization rate was high. Expression of ctsd, ctsl and lpl, however, did not show any significant differences. These results suggest that ctsb expression could be an indicator of egg quality, and that some proteins prone to be digested by ctsb could be very important in the process of fertilization and normal cleavage in this species. Further study should identify these critical proteins to improve our understanding on the quality of fish eggs.

• Animal cells and systems
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• 제11권2호
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• pp.117-124
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• 2007

The present study demonstrates the changes in body weight (BW) and plasma sex steroid hormone profiles during artificial maturation induced by human chorionic gonadotropin (HCG) or salmon pituitary extract (SPE) injections in cultured eel, Anguilla japonica, kept in seawater for 3 months. In the weekly SPE-injected female group, BW was relatively stable during vitellogenesis. Following induction of vitellogenesis, females exhibited a rapid increase of BW, and the oocytes were observed to be in the migratory nucleus stage at the end of the experiment. Plasma testosterone (T) and $estradiol-17{\beta}$ ($E_2$) levels increased slightly during vitellogenesis and peaked at an average of 5.82 ng/mL and 4.76 ng/mL, respectively, at the end of the experiment. In the weekly control and HCG-injected female groups, BW slowly decreased during the experimental period, and the oocytes of the two groups were observed to be at the primary yolk globule stage. In the weekly HCG-injected female group, plasma T and $E_2$ levels increased slightly during vitellogenesis and decreased afterward. In the control female group, however, plasma T and $E_2$ levels were not altered during the experimental period. Furthermore, plasma $17{\alpha},20{\beta}-dihydroxy-4-pregnen-3-one$ (DHP) was not detected in all experimental groups. Fertility and hatching rates of SPE-injected females were significantly higher in those that ovulated 15 h after DHP injection than 18 h. These results indicate that long rearing in seawater increases responsiveness to SPE in ovarian maturation of the Japanese eel, resulting in shortened period from completion of vitellogenesis by sex steroid hormone production.

• 한국식품영양과학회지
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• 제1권1호
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• pp.17-24
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• 1972

붕장어의 선어(鮮魚) 및 천일건조중(天日乾燥中)의 산가용성(酸可溶性) 핵산관련물질(核酸關聯物質)의 변화(變化)를 실험(實驗)하여 다음과 같은 결과를 얻었다. 1. 생붕장어에는 IMP함량(含量)이 월등하게 많았고, ATP, ADP, AMP 및 inosine, hypoxanthine은 양(量)이 적었다. 2. 천일건조중(天日乾燥中) ATP, ADP, AMP는 거의 완전(完全)히 소실(消失)되었고, 생원료중(生原料中)에 가장 많았던 IMP$(16{\mu}moles/g,\;dry\;base)$도 1/16로 감소(減少)하였다. 한편 inosine은 12배로 hypoxanthine은 약 3배로 증가(增加)하였다. 3. flavor quality 면으로 판단한다면 천일건조중(天日乾燥中)은 붕장어 가공법(加工法)으로서 효과적(效果的)인 방법(方法)이 못된다고 볼 수 있다.

• 수산해양기술연구
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• 제40권1호
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• pp.60-64
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• 2004

우리나라 남해안에서 플라스틱 붕장어 통발을 사용하는 통발어선이 연간 유실하는 통발의 개수는 통상 조업시 시용하는 통발의 2~4배인 것으로 나 타났다. 이러한 통발의 유실은 보통 조업중에 발생되므로 어구의 유실과 함께 어획물의 손실도 발생하게 된다. 어획불과 미끼가 들어있는 유실된 통발 은 붕장어뿐만 아니라 다른 해양 생물을 유인하여 어획할 수 있는 것으로 밝혀졌다. 그리고 유실된 붕장어 통발에는 어류, 갑각류, 두족류 등이 들어있었고, 이들 가운데는 붕장어의 먹이가 되는 베도라치, 청보리멸, 양태, 붉은메기와 새우류 등이 어획되어 있었다. 따라서 조업시 어획된 붕장어 이외에도 붕장어가 이들 통발 속에 들어있는 어획물을 섭이하기 위해 통발에 들어가므로서 추가적인 Ghost fishing의 가능성은 크다고 할 수 있다.

• 한국수산과학회지
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• 제44권3호
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• pp.237-242
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• 2011

To evaluate the proximate composition and main nutritive ingredients (vitamin A, $V_A$; vitamin E, $V_E$; cholesterol; the composition of fatty acids) between eels cultured in different domestic eel farms, we analyzed edible parts of eels that were cultured in three "Water Recirculation System (WRS)" farms and three "Still-Water System (SWS)" farms. We found differences in crude protein, crude lipids and the ash content of eel meat between the farms, but water content showed no significant difference. $V_A$ and $V_E$ contents did not show meaningful differences between the two culture methods, but there was a noticeable distinction between the eel farms. In particular, $V_E$ content showed significant differences between the eels of each farm (highest farm, about 25 mg/100 g dry wt; lowest farm, about 1 mg/100 g dry wt). The fatty acids of cultured eels were composed of monoenes (MUFA, 55-60%), saturates (SFA, 30-33%), $\omega$-6 highly unsaturates (HUFA, 1.6-2%) and $\omega$-3 HUFA (8-9.2%). The MUFA content of WRS eels ($59.9{\pm}1.97%$) was higher than that of SWS eels ($55.8{\pm}0.48%$). The contents of other fatty acids were higher in SWS eels (SFA, $33.0{\pm}0.52%$; $\omega$-6FUFA, $1.98{\pm}0.2%$; $\omega$-3 HUFA, $9.2{\pm}0.67%$) than in WRS eels (SFA, $30.5{\pm}1.34%$; $\omega$-6 HUFA, $1.62{\pm}0.19%$; $\omega$-3 HUFA, $8.0{\pm}0.5%$).

• Fisheries and Aquatic Sciences
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• 제16권2호
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• pp.85-92
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• 2013

To determine the relative importance of two main factors, diet or culture environment, that affect the proximate composition and main nutritive ingredients (vitamin A, vitamin E, cholesterol, fatty acid composition) in cultured eels, we analyzed the composition of eels fed diets of formula feed (FF) produced by four different companies and of eels cultured at five different eel farms that provided only one of the four different FFs. The four commercial eel FFs did not markedly differ in proximate composition or major nutritive compounds, and consequently, these variables did not significantly differ in cultured eels fed the different FFs. The FF imported from Japan was marginally superior to the two domestic commercial FFs and the FF imported from Taiwan in terms of the proximate composition and main nutritive ingredients of both the FF itself and the eels cultured on it. However, proximate composition and main nutritive ingredients significantly differed among eels cultured at the five farms that used a different FF and among eels fed the four different FFs at the same farm. In conclusion, the difference in quality between domestic and Japanese FFs in terms of eel culture was small, whereas physical or chemical environmental differences among farms during eel culture may more strongly affect the proximate composition and levels of the main nutritive ingredients in cultured eels.

• 한국어병학회지
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• 제21권3호
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• pp.219-228
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• 2008

The effects of dietary yeast β-glucan administration on growth, nonspecific immune responses, serum lysozyme, skin mucous lysozyme, NBT (nitroblue tetrazolium) reduction by phagocytes, and disease resistance against Edwardsiella tarda in Japanese eel, Anguilla japonica were evaluated. Fish were fed the diets supplemented with 0%, 0.1% and 0.5% of yeast β-glucan to a commercial diet for 6 weeks. The body weight gain from the fish fed on the 0.5% supplemented diet for 6 weeks was significantly higher than the control. Both serum and skin mucous lysozyme were significantly higher in the all experimental groups except 2 weeks of 0.5% group. The bactericidal activity of serum was slightly increased at 6 weeks. Also, The intracellular superoxide anion production of kidney phagocytes was significantly higher in the all experimental groups. The diet supplemented with 0.1% were also found to raise the relative percent survival (RPS) of Japanese eel after an artificial challenge with 1×107 cells of Edwardsiella tarda per fish. The results suggested the potential of yeast β-glucan to activate some innate immune responses and to improve the growth in Japanese eel.

• 한국수산과학회지
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• 제18권1호
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• pp.44-51
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• 1985

빙장 및 동결저장한 잉어와 붕장어의 어묵 가공원료로서의 적성에 대하여 실험한 것을 요약하면 다음과 같다. 1. K값, VBN, 생균수, pH및 관능검사 결과로 미루어 보아 어묵가공원료로서의 빙장한계는 잉어인 경우 약 16일이었고 붕장어는 약 13 일이었다. 또한 $-30^{\circ}C$, 3개월 동결저장중에는 양시료 모두 그 원료의 품질이 양호한 편이었다. 2. 저온저장에 대한 내성은 잉어가 붕장어보다 다소 강한 편이었다. 3. 제품의 품질특성시험으로서 겔강도, 절곡시험, 보수력, 색조, texture의 측정결과와 관능검사결과로 미루어 보아 빙장시료중 잉어는 빙장 10 일까지 제품품질이 우수하였고 빙장 16 일까지 어묵원료로서 이용 가능하다고 인정되었으며 붕장어인 경우, 빙장 8일까지 제품이 우수하였고 빙장 13일까지 이용가치가 있는 것으로 나타났다. 4. 동결저장한 시료로 만든 어묵제품은 양시료 모두 원료 저장 3개월까지 어묵제품 품질이 양호하였으며, 3개월간 동결저장한 원료의 어묵제품 품질은 잉어인 경우 빙장 $3{\sim}4$일째의 것과, 붕장어는 빙장 $4{\sim}6$ 일째의 것과 그 품질이 각각 서로 유사하였다.

• 한국발생생물학회지:발생과생식
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• 제25권4호
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• pp.269-277
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• 2021

Effects of water temperature and hormones on ovarian development of conger eel in Korea were investigated. Ovarian development was analyzed by measuring gonadosomatic index (GSI) and oocyte diameter with histological methods. At rearing water temperatures of 12℃, 14℃, and 16℃, GSI value increased from 3.66 at the start of the experiment to 7.44, 8.82, and 7.34 at the end of the experiment, respectively. At rearing water temperatures of 12℃, 14℃, and 16℃, egg diameter increased from 245.11-300.25 ㎛ at the start of the experiment to 377.62-480.27 ㎛, 396.72-498.54 ㎛, and 382.29-475.69 ㎛ at the end of the experiment, respectively. Follicular oocyte development revealed that primary yolk globule stage observed from January to March. It entered to secondary yolk globule stage in April and remained at the same stage until July. As a result of examining effects of three hormones (human chorionic gonadotropin (HCG), luteinizing hormone releasing hormone analogue (LHRHa), and salmon pituitary extraction (SPE) on ovarian development, HCG was found to be the most effective one. The progress from diapause of the secondary yolk globule stage to migratory nucleus stage of oocytes could be induced by treating fish with HCG at 1,000 IU/kg. The effect of hormone treatment on ovarian development of conger eel in Korea was the most effective at water temperature of 14℃.