Various aspects of the energetic response to handling stress in juvenile
coho salmon (Oncorhynchus kisutch) were examined. Fish were subjected to
four different handling stressors in a Blazka-style respirometer. Stressed fish
had rates of oxygen consumption that were higher than controls. The
magnitude of the increase ranged from 139 to 198% of the control value, and
appeared roughly related to the severity of the stressor. The post-stress
increase in oxygen consumption also appeared to vary seasonally, with less of
a stress effect on respiration observed in the spring as compared to the fall.
Elevation in oxygen consumption following stress was largely eliminated
within 1 h post-stress, but metabolic rate may have remained slightly elevated
for an additional 2 h.
Plasma cortisol and lactate titers also increased significantly following
handling stressors. Oxygen consumption was positively correlated with both
plasma cortisol and lactate after a moderate stressor, but no correlation was
found after more severe stressors. Whole body lactate concentration was
significantly elevated following stress, reaching levels almost 500% higher
than controls. By 5 h post-stress whole body lactate had returned to control
levels.
The mechanism of excess post-stress oxygen consumption remains
unclear. Fish given exogenous cortisol did not experience an increase in
oxygen consumption, so it is unlikely that cortisol alone has a major effect on
metabolic rate. Similarities between the energetic responses to both stress and
exercise suggest that the results of exercise physiology may provide a basis for
understanding the energetic response to stress. / Graduation date: 1993
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36459 |
| Date | 16 February 1993 |
| Creators | Davis, Lawrence E. (Lawrence Edward), 1965- |
| Contributors | Schreck, Carl B. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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