The effects of multiple stressors (diltiazem, hypoxia, and temperature) on the cardiovascular function of rainbow trout

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Keller, Antonio Goes Ferreira dos Santos
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta : University of Lethbridge, Dept. of Biological Sciences
The effects of climate change, hypoxia of surface waters, disposal of pharmaceuticals, among other stressors to freshwater ecosystems, are important concerns of modern civilization. Diltiazem (DTZ) is a calcium channel blocker prescribed for heart diseases in humans; however, the knowledge of the effects of DTZ in the aquatic environment is limited. The present study investigated the cardiovascular effects of DTZ in rainbow trout. Fish were exposed in the laboratory to DTZ (0, 1, 10, 100 and 1000μg/L) for 96 hours at different temperatures (4ºC, 10ºC and 18ºC) and different dissolved oxygen concentrations (4mg/L and 8mg/L). DTZ (1 and 10 μg/L) impaired the increase of hemoglobin under hypoxia, at 1 μg/L impaired the increase of the ventilation rate, and at 10 μg/L increased the immature RBC counts, suggesting impairment of the cardiovascular system of rainbow trout. No statistically significant effects of DTZ on heart rate, oxygen consumption or hematocrit were detected.
DTZ , fish cardiovascular performance , hemoglobin synthesis , hypoxic conditions , multiple stressor environment , temperature