Journal of Aquaculture (한국양식학회지)

The Korean Society of Fisheries and Aquatic Science (한국양식학회)
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Plasma Sex Steroid Hormone Profiles in Artificially Maturing Wild Eel, Anguilla japonica

자연산 뱀장어의 인위적인 성숙 유도에 따른 혈중 성호르몬 변동

  • 김대중 (국립수산과학원 수산생명과학본부 양식연구팀) ;
  • 김응오 (국립수산과학원 수산생명과학본부 양식연구팀) ;
  • 박민우 (국립수산과학원 수산생명과학본부 양식연구팀) ;
  • 조용철 (국립수산과학원 내수면양식연구소) ;
  • 임상구 (국립수산과학원 내수면양식연구소)
  • Published : 2006.11.25
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Abstract

To understand the changes in plasma levels of sex steroids in the wild Japanese eel Anguilla japonica during artificially maturing process, eels received weekly intraperitoneal injections of a water-in-oil (W/O) type emulsion with Freund`s incomplete adjuvant containing salmon pituitary extract (SPE; 20 mg pituitary powder/fish) were examined. In the weekly Eel's Ringer-treated control wild eels, the body weight (BW) changes of fish decreased slowly during the experiment period. Plasma testosterone (T), $estradiol-17{\beta}\;(E_2)$ and $17a,20{\beta}-dihydroxyprogesterone$ (DHP) levels did not change significantly at the end of the experiment. In the weekly SPE-treated silver eels, however, rapid increase in BW changes occurred after 6 to 10 weeks, and the oocytes of all fish were observed to be in the migratory nucleus stage. Furthermore, significant increase in sex steroid hormones (T and $E_2$) levels occurred from 6 weeks. In the weekly SPE-treated yellow eels, the BW changes of fish increased slowly at 6 weeks and then increased. In these fish, the oocytes were at the tertiary yolk globule stage even at the end of the experiment. Plasma sex steroid hormones profiles revealed individual variability in SPE-treated yellow eels. Plasma T and $E_2$ levels significantly increased at 8 weeks and after 6 weeks, respectively, in SPE-treated yellow eels. In the weekly SPE-treated wild eels (silver and yellow eels), however, plasma DHP levels did not change significantly during the experiment period. In silver eel, final maturation could be induced by weekly administration of SPE using W/O type emulsion.

자연산(silver 및 yellow) 뱀장어의 인위적인 성성숙 과정중에 체중 및 혈중 성호르몬 농도를 조사하기 위해 연어 뇌하수체 추출물(SPE; 20 mg pituitary powder/fish)를 Freund's incomplete adjuvant로 water-in oil (W/O) 형태로 유화시켜 매주 복강에 주사하였다. Eel's Ringer액만으로 유화시켜 주사한 대조구(silver 및 yellow) 뱀장어의 경우, 체중은 서서히 감소하는 경향을 나타내었으며, 혈중 성호르몬(testosterone; T, $estradiol-17{\beta};\;E_2$ 및 $17{\alpha},20{\beta}-dihydroxyprogesterone$; DHP)의 농도도 실험기간 동안 거의 변화없이 서서히 감소하는 경향을 나타냈었지만 유의적인 변화는 없었다. 한편, 매주 SPE로 주사한 silver 뱀장어는 투여 6주후부터 급격한 체중변화가 일어났으며, 대부분 개체의 난모세포는 핵이동기로 구성되어져 있었다. 또한 혈중 T와 $E_2$ 농도의 두드러진 증가는 투여 6주후부터 관찰되어 졌다. 매주 SPE로 주사한 yellow 뱀장어의 경우, 대부분 개체는 투여 5주까지 체중 변화가 완만하게 나타났으며 그 이후 급속히 증가하였다. 이들 개체의 대부분은 실험종료시에도 제3 난황구기의 난모세포들로 구성되어져 있었다. 특히 실험 기간중 혈중 T와 $E_2$ 농도는 개체별로 다양하게 나타났으며, 유의한 차이는 제각기 투여 8주째와 투여 6주 후 부터 두드러지게 증가하였다. 그러나 매주 SPE로 주사한 자연산 뱀장어(silver 및 yellow)의 혈중 DHP 농도는 실험 기간동안 불검출 혹은 매우 낮은 농도로 유지하였으며, 유의적인 변화는 관찰되지 않았다. 본 연구의 결과, sliver 뱀장어에 있어서 SPE를 W/O 형태로 유화시켜 반복 투여함으로써 체중 및 혈중 성호르몬(T와 $E_2$)의 급격한 증가 및 최종성숙을 유도하는데 효과적이었다.

Keywords

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