+ Site Statistics
References:
54,258,434
Abstracts:
29,560,870
PMIDs:
28,072,757
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Long-term hypoxia exposure alters the cardiorespiratory physiology of steelhead trout (Oncorhynchus mykiss), but does not affect their upper thermal tolerance



Long-term hypoxia exposure alters the cardiorespiratory physiology of steelhead trout (Oncorhynchus mykiss), but does not affect their upper thermal tolerance



Journal of Thermal Biology 68(Pt B): 149-161



It has been suggested that exposure to high temperature or hypoxia may confer tolerance to the other oxygen-limited stressor (i.e., 'cross-tolerance'). Thus, we investigated if chronic hypoxia-acclimation (>3 months at 40% air saturation) improved the steelhead trout's critical thermal maximum (CTMax), or affected key physiological variables that could impact upper thermal tolerance. Neither CTMax (24.7 vs. 25.3°C) itself, nor oxygen consumption ( [Formula: see text] ), haematocrit, blood haemoglobin concentration, or heart rate differed between hypoxia- and normoxia-acclimated trout when acutely warmed. However, the cardiac output (Q̇) of hypoxia-acclimated fish plateaued earlier compared to normoxia-acclimated fish due to an inability to maintain stroke volume (SV), and this resulted in a ~50% lower maximum Q̇. Despite this reduced maximum cardiac function, hypoxia-acclimated trout were able to consume more O2 per volume of blood pumped as evidenced by the equivalent [Formula: see text] . These results provide additional evidence that long-term hypoxia improves tissue oxygen utilization, and that this compensates for diminished cardiac pumping capacity. The limited SV in hypoxia-acclimated trout in vivo was not associated with changes in cardiac morphology or in vitro maximum SV, but the affinity and density of myocardial ß-adrenoreceptors were lower and higher, respectively, than in normoxia-acclimated fish. These data suggest that alterations in ventricular filling dynamics or myocardial contractility constrain cardiac function in hypoxia-acclimated fish at high temperatures. Our results do not support (1) 'cross-tolerance' between high temperature and hypoxia when hypoxia is chronic, or (2) that cardiac function is always the determinant of temperature-induced changes in fish [Formula: see text] , and thus thermal tolerance, as suggested by the oxygen- and capacity-limited thermal tolerance (OCLTT) theory.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 059927163

Download citation: RISBibTeXText

PMID: 28797475

DOI: 10.1016/j.jtherbio.2016.03.007


Related references

Physiology and mRNA expression in rainbow trout (Oncorhynchus mykiss) after long-term exposure to the new antifoulant medetomidine. Comparative Biochemistry and Physiology. Toxicology and Pharmacology 154(3): 234-241, 2012

Selection for upper thermal tolerance in rainbow trout (Oncorhynchus mykiss Walbaum). Journal of Experimental Biology 218(Pt 5): 803-812, 2015

Thermal limits on the ocean distribution of steelhead trout (Oncorhynchus mykiss). North Pacific Anadromous Fish Commission Bulletin (1): 396-404, 1998

Blood Oxygenation and Cardiorespiratory Function in Steelhead Trout Oncorhynchus mykiss Challenged with an Acute Temperature Increase and Zatebradine-Induced Bradycardia. Journal of Thermal Biology 37(3): 0-210, 2012

Comparisons between hatchery and wild steelhead trout (Oncorhynchus mykiss) smolts: physiology and habitat use. Canadian Journal of Fisheries and Aquatic Sciences 63(7): 1627-1638, 2006

Quantitative trait loci for upper thermal tolerance in outbred strains of rainbow trout (Oncorhynchus mykiss). Heredity 86(3): 333-341, 2001

Genetic parameters for upper thermal tolerance and growth-related traits in rainbow trout (Oncorhynchus mykiss). Aquaculture 250(1/2): 120-128, 2005

Low toxicity of the black fly larvicide Bacillus thuringiensis var. israelensis to early stages of brook trout (Salvelinus fontinalis), brown trout, (Salmo trutta), and steelhead trout (Oncorhynchus mykiss) following direct and indirect exposure. Canadian Journal of Fisheries and Aquatic Sciences 51(6): 1451-1458, 1994

Maintenance of steelhead trout (Oncorhynchus mykiss) sperm at different in vitro oxygen tensions alters ATP levels and cell functional characteristics. Fish Physiology and Biochemistry 21(3): 193-200, 1999

Hybridization with domesticated rainbow trout (Oncorhynchus mykiss) reduces seasonal variation in growth of steelhead trout (O. mykiss). Canadian Journal of Fisheries and Aquatic Sciences 50(3): 480-487, 1993

Seasonal changes in osmoregulation, cortisol, and cortisol receptor activity in the gills of parr/smolt of steelhead trout and steelhead-rainbow trout hybrids, Oncorhynchus mykiss. General and Comparative Endocrinology 93(1): 103-113, 1994

The effects of endothelin-1 on the cardiorespiratory physiology of the freshwater trout (Oncorhynchus mykiss) and the marine dogfish (Squalus acanthias). Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology 171(8): 623-634, 2002

The effects of endothelin-1 on the cardiorespiratory physiology of the freshwater trout (Oncorhynchus mykiss) and the marine dogfish (Squalus acanthias). Journal of Comparative Physiology B Biochemical Systemic and Environmental Physiology 171(8): 623-634, 2001

Hardness does not affect the physiological responses of wild and domestic strains of diploid and triploid rainbow trout Oncorhynchus mykiss to short-term exposure to pH 9.5. Journal of Fish Biology 89(2): 1345-1358, 2017

Cytopathology of liver and kidney in rainbow trout Oncorhynchus mykiss after long-term exposure to sublethal concentrations of linuron. Diseases of Aquatic Organisms 21(1): 35-52, 1995