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Cui W, Takahashi E, Morro B, Balseiro P, Albalat A, Pedrosa C, Mackenzie S, Nilsen TO, Sveier H, Ebbesson LO, Handeland SO, Shimizu M. Changes in circulating insulin-like growth factor-1 and its binding proteins in yearling rainbow trout during spring under natural and manipulated photoperiods and their relationships with gill Na +, K +-ATPase and body size. Comp Biochem Physiol A Mol Integr Physiol 2022; 268:111205. [PMID: 35346822 DOI: 10.1016/j.cbpa.2022.111205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/10/2022] [Accepted: 03/22/2022] [Indexed: 10/18/2022]
Abstract
Smoltification in salmonids occurs during spring in response to increasing photoperiod to prepare for marine life. Smoltification is associated with increased hypo-osmoregulatory ability and enhanced growth potential, mediated by growth hormone and insulin-like growth factor (IGF)-1. Rainbow trout is uniquely insensitive to the induction of smoltification-associated changes by photoperiod, such as the activation of gill Na+,K+-ATPase (NKA). We measured the circulating IGF-1 and IGF-binding protein (IGFBP)-2b levels in yearling rainbow trout exposed to natural and manipulated photoperiods during spring and correlated these with gill NKA activity and body size. Although the effect of photoperiod manipulation on body size and circulating IGF-1 and IGFBP-2b was negligible, they were positively correlated with gill NKA activity in fish under simulated natural photoperiod. We next pit-tagged yearling rainbow trout and fed them a restricted ration or to satiation under a natural photoperiod. In April, gill NKA activity was higher in the satiation group than in the restricted group and positively correlated with body size and growth rate. In addition, circulating IGFBP-2b was positively correlated with gill NKA, size and growth, whereas circulating IGF-1 was correlated only with size and growth. The relationship between circulating IGF-1 and growth intensified from May to June, suggesting that the IGF-1-growth relationship was disrupted in April when gill NKA was activated. Two additional IGFBPs were related to growth parameters but not to gill NKA activity. The present study suggests that circulating IGFBP-2b and IGF-1 mediate the size-dependent activation of gill NKA in yearling rainbow trout during spring.
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Affiliation(s)
- Wenda Cui
- Graduate School of Environmental Science, Hokkaido University, Kita 10, Nishi 5, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Eisuke Takahashi
- Nanae Fresh-Water Station, Field Science Center for Northern Biosphere, Hokkaido University, 2-9-1 Sakura, Nanae, Kameda-gun, Hokkaido 041-1105, Japan
| | - Bernat Morro
- Institute of Aquaculture, University of Stirling, FK9 4LA Stirling, UK
| | - Pablo Balseiro
- NORCE AS, Nygårdsgaten 112, 5008 Bergen, Norway; Department of Biological Sciences, University of Bergen, Thormøhlens gate 53 A/B, 5020 Bergen, Norway
| | - Amaya Albalat
- Institute of Aquaculture, University of Stirling, FK9 4LA Stirling, UK
| | - Cindy Pedrosa
- NORCE AS, Nygårdsgaten 112, 5008 Bergen, Norway; Department of Biological Sciences, University of Bergen, Thormøhlens gate 53 A/B, 5020 Bergen, Norway
| | - Simon Mackenzie
- Institute of Aquaculture, University of Stirling, FK9 4LA Stirling, UK; NORCE AS, Nygårdsgaten 112, 5008 Bergen, Norway
| | - Tom O Nilsen
- NORCE AS, Nygårdsgaten 112, 5008 Bergen, Norway; Department of Biological Sciences, University of Bergen, Thormøhlens gate 53 A/B, 5020 Bergen, Norway
| | - Harald Sveier
- Lerøy Seafood Group ASA, Box 7600, 5020 Bergen, Norway
| | | | - Sigurd O Handeland
- NORCE AS, Nygårdsgaten 112, 5008 Bergen, Norway; Department of Biological Sciences, University of Bergen, Thormøhlens gate 53 A/B, 5020 Bergen, Norway
| | - Munetaka Shimizu
- Section of Aquatic Research, Field Science Center for Northern Biosphere, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido 041-8611, Japan.
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