• 생명과학회지
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• 제23권10호
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• pp.1288-1294
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• 2013

뱀장어 자어의 형태변화에 관한 연구는 자어의 인공사육을 위해 알아야 할 중요한 부분이다. 본 연구에서는 두부의 형태학적 관찰과 함께, 부화 이후 변태 직후까지의 단계별 안구의 조직학적인 변화를 관찰하였다. 이들 결과로 부화 후 100일과 변태를 기점으로 상악과 하악의 발달에 큰 차이를 관찰할 수 있었으며, 치아는 실뱀장어로 변태하면서 퇴화한다는 것을 알 수 있었다. 안구 망막에서의 조직학적인 주요 변화는 부화 100일 이후의 OPL (outer plexiform layer)과 ONL (outer nuclear layer)의 형성과 변태 이후 간상세포층의 변화이며, 안구의 각막은 부화 10일째 자어에서 관찰되지 않았지만 이후 모든 단계에서 관찰되었다. 실뱀장어의 양산을 위해 초기 자어의 발달에 관한 더 많은 정보가 필요하며, 본 결과가 자어의 인공사육시스템 안정화에 도움이 될 것으로 기대한다.

• 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.

• 수산해양교육연구
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• 제26권6호
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• pp.1402-1411
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• 2014

This study about morphological observation of pre- or post ovulated eggs obtained from artificially maturated female eels. Female eels were divided with two groups as wild eels from nature and feminized eels from farm. Artificial maturation had been conducted with the established methods in this laboratory, and then maturate eggs sampled at fixed 3 times and these were observed with stereomicroscope. Rate of increased body weight (RIW) were measured with 2 times. Egg diameters and development of oil droplets are determined for standardization of egg maturation degree, and the transparency of egg cytoplasm and the homogeneous degrees of egg size were referred to determine of egg quality. Rate of increased body weight (RIW) were good in range about 10 % at final salmon pituitary extracts (SPE) injection time and in range about 20 % at $17{\alpha}$, $20{\beta}$-dihydroxy-4-pregnen-3-one (DHP) injection time. Good matured egg for fertilization had $900-1000{\mu}m$ diameter, and they had about 50 oil droplets in size about $100{\mu}m$ diameter. There were not predominant differences at egg size and oil droplet development between wild female and feminized 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.