Utilization of Hypothalamic Hormones for Maturational Induction in Seawater Chum Salmon, Oncorhynchus keta

해면연어의 성숙을 유도하기 위한 시상하부호르몬의 이용

  • Park, Woo-Dong (Faculty of Marine Bioscience and Technology, Kangnung National University) ;
  • Lee, Cheul-Ho (Yeongdong Inland Fisheries Research institute, National Fisheries Research and Development Institute) ;
  • Shon, Young-Chang (Faculty of Marine Bioscience and Technology, Kangnung National University)
  • 박우동 (강릉대학교 해양생명공학부) ;
  • 이철호 (국립수산과학원 영동내수면연구소) ;
  • 손영창 (강릉대학교 해양생명공학부)
  • Published : 2007.05.31

Abstract

Freshwater-adapted maturing chum salmon (Oncorhynchus keta) involuntarily captured by stationary nets in Yang-yang seashore areas were transferred to freshwater in an outdoor raceway tank at Yeongdong Inland Fisheries Research Institute, NFRDI, Yang-yang, Gangwon, Korea and kept over 1 day until the start of the experiments. The freshwater-adapted females were single-injected intraperitoneally with gonadotropin-releasing hormone analogue, (GnRH-a: $70\;{\mu}g/kg$ body weight, BW) alone or combined with a dopamine receptor antagonist, pimozide($700\;{\mu}g/kg$ BW). Although gonadosomatic indices [GSI, (gonad weight/BW)${\times}100$] did not show significant changes in both 2004 and 2005, GSI of GnRH-a-injected fish during the 2005 trial slightly increased on the 5th and 7th days post-injection compared to those of vehicle treated fish. Hepatosomatic indices [HSI, (liver weight/BW)${\times}100$] of fish injected with GnRH-a alone and combined with pimozide decreased significantly on the 7th day post-injection in 2004(P<0.05). In 2005 trials, HSI was significantly reduced in GnRH-a treated fish on the 7th day post-injection (P<0.05). Pimozide-injected fish showed a pattern with increase of GSI and decrease of HSI, without significant differences. Taken together, these results suggest that at least in part hypothalamic hormones and dopamine receptor antagonist may induce sexual maturation in freshwater-adapted maturing chum salmon. It remains to evaluate these preliminary results by further researches.

강원도 양양군 연안으로 회귀한 성숙중의 연어(Oncorhynchus keta)를 국립수산과학원 영동내수면연구소로 수송하고 담수에 1일 이상 순치시킨 후, GnRH 유사체(GnRH-a)와 시상하부 도파민수용체의 길항제인 pimozide를 복강에 주사하여 생식소중량지수[GSI, (생식소중량/체중량)${\times}100$]와 간중량지수[HSI, (간중량/체중량)${\times}100$]의 변화를 조사하였다. GnRHa와 pimozide는 각각 $70\;{\mu}g$$700\;{\mu}g/kg$ 어체중 농도로 단독 또는 혼합주사하여 주사후 7일째까지 조사하였다. 2004년도의 실험에서는 GSI의 유의적인 변화가 없었다. 2005년도에도 유의적인 변화가 없었지만, 5일째 및 7일째에는 호르몬 주사군에서 약간 증가하는 경향이 관찰되었다. HSI는 주사후 7일째에 대조군에 비하여 GnRH-a 주사군 및 pimozide 혼합 주사군에서 유의적으로 감소하였다 (2004년; P<0.05). 2005년도에도 호르몬 주사군에서 HSI는 전체적으로 감소하는 결과이었으나, GnRH-a 주사후 7일째의 연어에서만 유의적으로 감소하였다(P<0.05). pimozide를 단독주사 한 2005년도의 실험에서는 유의차는 없었지만, GSI는 증가하고 HSI는 감소하였다. 따라서 성숙중인 해면연어가 연안에서 포획되었을 경우에는 담수에 일시적으로 순치시킨 다음, 시상하부호르몬 및 도파민 길항제를 주사하면 최종성숙을 조기에 유도할 수 있음이 부분적으로 시사되었으며, 향후 이에 대한 효과가 검증될 수 있게 되기를 바란다.

Keywords

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