2022 Fiscal Year Final Research Report

Diagnosing growth and stress status of cultured salmonids through understanding the growth mechanism

Research Project

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Project/Area Number	19H03024
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 40030:Aquatic bioproduction science-related
Research Institution	Hokkaido University
Principal Investigator	Shimizu Munetaka 北海道大学, 北方生物圏フィールド科学センター, 教授 (90431337)
Co-Investigator(Kenkyū-buntansha)	棟方有宗宮城教育大学, 教育学部, 准教授 (10361213) 森山俊介北里大学, 海洋生命科学部, 教授 (50222352) 内田勝久宮崎大学, 農学部, 教授 (50360508)
Project Period (FY)	2019-04-01 – 2023-03-31
Keywords	成長 / ホルモン / サケ科魚類 / 海面養殖 / 指標
Outline of Final Research Achievements	This project aimed to understand the mechanism of growth regulation by insulin-like growth factor (IGF) and its binding proteins (IGFBPs) in salmonids and develop diagnosis tools to evaluate their growth and stress. We produced recombinant proteins for four IGFBP-1 subtypes and compared their IGF-1-inhibitory activity. Recombinant IGFBP-2b, a major carrier of circulating IGF-1, was also produced and used to establish a time-resolved fluoroimmunoassay. Using ligand blotting and immunoassay, we revealed that in rainbow trout circulating IGF-1 and IGFBP-2b could be used as growth indices. On the other hand, IGFBP-1a and -1b were rarely detected in trout serum, suggesting that domestication might reduce the sensitivity of these growth-inhibitory IGFBP subtypes. Gene editing of IGFBP-2b in rainbow trout resulted in its knock-out/-down. Their offspring will be useful to unravel function of IGFBP-2b and compensatory response by other IGFBPs.
Free Research Field	魚類生理学
Academic Significance and Societal Importance of the Research Achievements	本研究成果の学術的意義は、まず、サケ科魚類に特有の全ゲノム重複により生じた4種のIGFBP-1サブタイプ全てに対して組換えタンパクを作製して機能解析を行った点である。そして、ゲノム編集によりIGFBP-2bノックアウトニジマス作出の道筋を付けたことで、今後の研究の発展が期待されるのも学術的に意義がある。また、組換えタンパクを活用してIGFBP-2bに対する測定系を確立し、本タイプの血中量測定により養殖魚の成長を評価できる可能性を示した点が社会的意義として挙げられる。