This thesis tests the hypothesis that innate immunity may be enhanced
immediately following a stressful event. The experiments characterize the acute
effects of the fight or flight response on some immunological and endocrine
parameters in rainbow trout (Oncorhynchus mykiss). Plasma cortisol and
catecholamines were elevated within seconds of the initiation of an acute
handling stressor consisting of 30 seconds in the air and five, 10 or 20 minutes in
a shallow bucket of water. Plasma lysozyme activity increased after stress,
however, the increases were not statistically significant unless variation was
reduced by serial bleeding of the same individual trout before and after stress. A
more "resting" fish was achieved by use of the anesthetic 2-phenoxy-ethanol
which was surreptitiously introduced into the tanks before the initial bleed.
Individual fish were then revived in freshwater and stressed as before.
Enhancement of lysozyme activity was evident although levels of plasma stress
hormones in fish that were anesthetized, revived and stressed were less than
when fish were similarly stressed without anesthetic. Levels of cortisol and
catecholamines increased within seconds of capture and aerial exposure,
returned to near pre-stress levels after the fish had been placed in a shallow
bucket of water for 30 seconds, then increased again. Evaluation of the influence
of acute stress on survival following challenge with the pathogen Vibrio
anguillarum yielded equivocal data. Results presented here suggest that
enhancement of innate defenses as part of the fight or flight response merits
further evaluation. / Graduation date: 1997
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34210 |
| Date | 11 June 1996 |
| Creators | Demers, Nora Egan |
| Contributors | Bayne, Christopher J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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