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Abstract

Hyperoxia has been shown to expand the aerobic capacity of some fishes, although there have been very few studies examining the underlying mechanisms and how they vary across different exposure durations. Here, we investigated the cardiorespiratory function of yellowtail kingfish (Seriola lalandi) acutely (similar to 20 h) and chronically (3-5 weeks) acclimated to hyperoxia (similar to 200% air saturation). Our results show that the aerobic performance of kingfish is limited in normoxia and increases with environmental hyperoxia. The aerobic scope was elevated in both hyperoxia treatments driven by a similar to 33% increase in maximum O-2 uptake (MO2max), although the mechanisms differed across treatments. Fish acutely transferred to hyperoxia primarily elevated tissue O-2 extraction, while increased stroke volume-mediated maximum cardiac output was the main driving factor in chronically acclimated fish. Still, an improved O-2 delivery to the heart in chronic hyperoxia was not the only explanatory factor as such. Here, maximum cardiac output only increased in chronic hyperoxia compared with normoxia when plastic ventricular growth occurred, as increased stroke volume was partly enabled by an similar to 8%-12% larger relative ventricular mass. Our findings suggest that hyperoxia may be used long term to boost cardiorespiratory function potentially rendering fish more resilient to metabolically challenging events and stages in their life cycle.

Keywords

hyperoxia; aerobic scope; cardiovascular function; tissue O-2 extraction

Published in

Proceedings of the Royal Society B: Biological Sciences
2024, volume: 291, number: 2025, article number: 20232557
Publisher: ROYAL SOC

SLU Authors

Global goals (SDG)

SDG14 Life below water

UKÄ Subject classification

Fish and Aquacultural Science

Publication identifier

  • DOI: https://doi.org/10.1098/rspb.2023.2557

Permanent link to this page (URI)

https://res.slu.se/id/publ/141181