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Circulatory limits to oxygen supply during an acute temperature increase in the Chinook salmon (Oncorhynchus tshawytscha)

Citation

Clark, TD and Sandblom, E and Cox, GK and Hinch, SG and Farrell, AP, Circulatory limits to oxygen supply during an acute temperature increase in the Chinook salmon (Oncorhynchus tshawytscha), Comparative Biochemistry and Physiology. Part A, 295, (5) pp. R1631-R1639. ISSN 1095-6433 (2008) [Refereed Article]

DOI: doi:10.1152/ajpregu.90461.2008

Abstract

This study was undertaken to provide a comprehensive set of data relevant to disclosing the physiological effects and possible oxygen transport limitations in the Chinook salmon (Oncorhynchus tshawytscha) during an acute temperature change. Fish were instrumented with a blood flow probe around the ventral aorta and catheters in the dorsal aorta and sinus venosus. Water temperature was progressively increased from 13C in steps of 4C up to 25C. Cardiac output increased from 29 to 56 mlmin−1kg−1 between 13 and 25C through an increase in heart rate (58 to 105 beats/min). Systemic vascular resistance was reduced, causing a stable dorsal aortic blood pressure, yet central venous blood pressure increased significantly at 25C. Oxygen consumption rate increased from 3.4 to 8.7 mgmin−1kg−1 during the temperature increase, although there were signs of anaerobic respiration at 25C in the form of increased blood lactate and decreased pH. Arterial oxygen partial pressure was maintained during the heat stress, although venous oxygen partial pressure (PvO2) and venous oxygen content were significantly reduced. Cardiac arrhythmias were prominent in three of the largest fish (>4 kg) at 25C. Given the switch to anaerobic metabolism and the observation of cardiac arrhythmias at 25C, we propose that the cascade of venous oxygen depletion results in a threshold value for PvO2 of around 1 kPa. At this point, the oxygen supply to systemic and cardiac tissues is compromised, such that the oxygen-deprived and acidotic myocardium becomes arrhythmic, and blood perfusion through the gills and to the tissues becomes compromised.

Item Details

Item Type:Refereed Article
Keywords:blood pressure, blood respiratory properties, cardiac output, hematocrit, hemoglobin, heart rate, blood plasma, rate of oxygen consumption, oxygen equilibrium curves, Pacific salmon, stroke volume, vascular resistance
Research Division:Biological Sciences
Research Group:Zoology
Research Field:Animal Behaviour
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Coastal and Estuarine Flora, Fauna and Biodiversity
UTAS Author:Clark, TD (Dr Timothy Clark)
ID Code:103460
Year Published:2008
Web of Science® Times Cited:93
Deposited By:IMAS Research and Education Centre
Deposited On:2015-10-12
Last Modified:2015-10-12
Downloads:0

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