2023 Fiscal Year Final Research Report
Blind side hypermelanosis and stress in heterosomata, by net-lined rearing and optmization of eggs
| Project/Area Number |
19K06237
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 40040:Aquatic life science-related
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Keywords | ヒラメ / カレイ類 / 無眼側黒化 / 網敷飼育 / ストレス / コルチゾル / 短躯症 / 性比の偏り |
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| Outline of Final Research Achievements |
Most of the farmed Japanese flounder has hypermelanosis on the blind side. In this study, we found that the darkening area can be largely reduced by setting a rough substrate (net, grazing, wire netting, for example) that covers about 50% of the tank bottom. On the other hand, presence of a hypermelanosis which strongly caused by genetic background was clarified. From this finding, the gate was opened to identify the gene crucial for the hypermelanosis, in other word, crucial for the normal process to maintain the white blind side. In addition to flounders, there are other undesirable phenomena in farmed fish of other species; the phenomena not found in wild fish. By examining the hypermelanosis of the body surface in barfin flounder and goldfish, body shortening in white whiting, and a male biased sex-ratio in barfin flounder, the stress expected in rearing tanks was suggested as a common possible factor for these undesirable phenomena.
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| Free Research Field |
魚類生理学
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| Academic Significance and Societal Importance of the Research Achievements |
養殖ヒラメは裏側にも黒色部分があるため、皮をひいた状態で消費者に届くルートで流通していると考えられる。本研究で開発した黒化の防除法は、養殖現場の大水槽に容易に応用できる。今後、裏側のきれいな養殖ヒラメが生産できるようになると、供給量や品質の安定している養殖ヒラメの価格競争力がさらに高まると期待できる。また、本研究によってヒラメの非対称性のカギとなる遺伝子の特定に道を開くことができた。さらに、飼育魚だけに見られる様々な好ましくない現象には、飼育自身によるストレスが原因となっている例が複数明らかとなった。このことは、ストレス軽減こそが、より良い飼育魚を育てるための基本戦略となりうることが示せた。
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