Temperature effects on aerobic scope and cardiac performance of European perch (Perca fluviatilis)

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Several recent studies have highlighted how impaired cardiac performance at high temperatures and in hypoxia may compromise the capacity for oxygen transport. Thus, at high temperatures impaired cardiac capacity is proposed to reduce oxygen transport to a degree that lowers aerobic scope and compromises thermal tolerance (the oxygen- and capacity-limited thermal tolerance (OCLTT) hypothesis). To investigate this hypothesis, we measured aerobic and cardiac performance of a eurythermal freshwater teleost, the European perch (Perca fluviatilis). Rates of oxygen consumption were measured during rest and activity at temperatures between 5 degrees C and 27 degrees C, and we evaluated cardiac function by in vivo measurements of heart rate and in vitro studies to determine contractility of myocardial strips. Aerobic scope increased progressively from 5 degrees C to 21 degrees C, after which it levelled off. Heart rate showed a similar response. We found little difference between resting and active heart rate at high temperature suggesting that increased cardiac scope during activity is primarily related to changes in stroke volume. To examine the effects of temperature on cardiac capacity, we measured isometric force development in electrically paced myocardial preparations during different combinations of temperature, pacing frequency, oxygenation and adrenergic stimulation. The force-frequency product increased markedly upon adrenergic stimulation at 21 and 27 degrees C (with higher effects at 21 degrees C) and the cardiac preparations were highly sensitive to hypoxia. These findings suggest that at (critically) high temperatures, cardiac output may diminish due to a decreased effect of adrenergic stimulation and that this effect may be further exacerbated if the heart becomes hypoxic. Hence cardiac limitations may contribute to the inability to increase aerobic scope at high temperatures in the European perch (Perca fluviatilis).

Original languageEnglish
JournalJournal of Thermal Biology
Volume68
IssuePart B
Pages (from-to)162-169
Number of pages8
ISSN0306-4565
DOIs
Publication statusPublished - Aug 2017

    Research areas

  • TROUT ONCORHYNCHUS-MYKISS, LIMIT THERMAL TOLERANCE, STANDARD METABOLIC-RATE, RAINBOW-TROUT, CLIMATE-CHANGE, CARDIORESPIRATORY PERFORMANCE, SALMON ONCORHYNCHUS, FORCE DEVELOPMENT, OXYGEN-TRANSPORT, TELEOST HEARTS

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