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

Wenda Cui; Eisuke Takahashi; Bernat Morro; Pablo Balseiro; Amaya Albalat; Cindy Pedrosa; Simon Mackenzie; Tom O Nilsen; Harald Sveier; Lars O Ebbesson; Sigurd O Handeland; Munetaka Shimizu

doi:10.1016/j.cbpa.2022.111205

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 Jun:268:111205. doi: 10.1016/j.cbpa.2022.111205. Epub 2022 Mar 25.

Authors

Affiliations

¹ Graduate School of Environmental Science, Hokkaido University, Kita 10, Nishi 5, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
² Nanae Fresh-Water Station, Field Science Center for Northern Biosphere, Hokkaido University, 2-9-1 Sakura, Nanae, Kameda-gun, Hokkaido 041-1105, Japan.
³ Institute of Aquaculture, University of Stirling, FK9 4LA Stirling, UK.
⁴ NORCE AS, Nygårdsgaten 112, 5008 Bergen, Norway; Department of Biological Sciences, University of Bergen, Thormøhlens gate 53 A/B, 5020 Bergen, Norway.
⁵ Institute of Aquaculture, University of Stirling, FK9 4LA Stirling, UK; NORCE AS, Nygårdsgaten 112, 5008 Bergen, Norway.
⁶ Lerøy Seafood Group ASA, Box 7600, 5020 Bergen, Norway.
⁷ NORCE AS, Nygårdsgaten 112, 5008 Bergen, Norway.
⁸ Section of Aquatic Research, Field Science Center for Northern Biosphere, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido 041-8611, Japan. Electronic address: mune@fish.hokudai.ac.jp.

PMID: 35346822
DOI: 10.1016/j.cbpa.2022.111205

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.

Keywords: Body size; Feeding restriction; Hypo-osmoregulatory ability; IGFBP-2b; Smoltification.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Body Size
Gills* / metabolism
Insulin-Like Growth Factor Binding Proteins
Insulin-Like Growth Factor I / metabolism
Oncorhynchus mykiss* / metabolism
Photoperiod
Sodium-Potassium-Exchanging ATPase / metabolism

Substances

Insulin-Like Growth Factor Binding Proteins
Insulin-Like Growth Factor I
Sodium-Potassium-Exchanging ATPase