Plasma cortisol stress response in fingerling rainbow trout, Salmo gairdneri Richardson, to various transport conditions, anaesthesia, and cold shock

Abstract

Plasma cortisol levels of fingerling rainbow trout were measured as an index of the stress resulting from various procedures used for transport of the fish for stocking. When transported under ' normal ' conditions, which included water at the hatchery acclimation temperature (10-1 1" C), 0, saturation or supersaturation, and neutral pH, there was a marked increase in plasma cortisol levels within 0.5 h, which was maintained over the next 4 h of transport; there was a significant decrease in plasma cortisol by 8 h of transport. It was found that the plasma cortisol levels at 4 and 8 h were not appreciably altered by transport under partial 0, desaturation, 0, saturation, 0, supersaturation, or 0.5% NaCI, or by anaesthesia with tricaine methanesulfonate (MS 222) prior to capture and transport in MS 222-free water or 0.5% NaCI. A 15 min exposure to an immobilizing dose ofbuffered or unbuffered MS 222, or 2-phenoxyethanol, caused an increase in plasma cortisol ofabout 2 h duration, indicating that anaesthetics are themselves stressful. Exposure to chilled water (1" C) caused a large increase in plasma cortisol levels by 4 h after initiation of exposure; plasma cortiso! had decreased at 1 day, and by 2 days a constant level was reached which was above the level in fingerling trout under ' normal ' hatchery conditions. Trout acclimated to chilled water for 24 h and transported in chilled water had an increase in plasma cortisol during transport. Anaesthesia prior to transport or addition of salt did not reduce the stress oftransport as judged by plasma cortisol levels. The results indicate that stress from capture and transport during stocking cannot be avoided using present methods.

Stress responses of the fish Nile tilapia subjected to electroshock and social stressors

“…Mean pre-stressor cortisol levels ranged from 41.57 to 65.67 ng/mL (Figure 2), in agreement with other studies. For instance, the baseline described for O. niloticus ranged from ~5 to 60 ng/mL (10,11,17,23,24), and for the related Cichlid, O. mossambicus, it ranged from ~20 to 60 ng/mL (33), and from about 10 to 60 for other fish species (3)(4)(5)(6)19,34).…”

“…On the other hand, intensity and duration are stressor characteristics that affect stress (1,2). Most investigations have concentrated on non-stressor factors modulating stressor effects (19,20), and much less emphasis has been placed on differences in fish stress response caused by putative stressor characteristics, which are thus the focus of the present study.…”

Physiological response of wild rainbow trout to angling: impact of angling duration, fish size, body condition, and temperature

“…The physiological stress response of fish anesthetized in MS-222 or clove oil solution has ranged from minimal to significant, largely depending on the duration of time fish are in the anesthetic, the specific anesthetic and dose, when the dose was delivered, and the species of study (Barton and Peter, 1982;Tort et al, 2002;Wagner et al, 2002). It should be recognized that some of the variation observed in physiological parameters measured when fish are under anesthesia following a stress event may be partially due to differences in anesthetization times, which can contribute to variation in sampling times and ultimately physiological changes.…”

Physiological stress responses in the warm-water fish matrinxã (Brycon amazonicus ) subjected to a sudden cold shock

“…Palmisano et al (2000) demonstrated that chinook salmon (Oncorhynchus tshawytscha) exposed to heat shock presented increased levels of HsP90 messenger rnA, but there was no concomitant increase in plasma cortisol levels. studies have also shown an endocrine stress response change in fish exposed to cold shock (Barton & Peter, 1982;Tanck et al, 2000;Chen et al, 2002). In these three studies, increased plasma cortisol levels were observed in rainbow trout, common carp (Cyprinus carpio) and tilapia aurea (Oreochromis aureus), respectively, exposed to cold shock (in different experimental conditions).…”

“…some of these parameters have been shown to change when fish are exposed to cold shock (In vivo studies: rainbow trout: Barton & Peter, 1982;tilapia aurea: Chen et al, 2002, Kindle & whitmore, 1986common carp: Tanck et al, 2000;milkfish: Hsieh et al, 2003; In vitro studies: rainbow trout rTG-2 cells: Yamashita et al, 1996; zebrafish Zf4 cells: Airaksinen et al, 2003). However, after fish had returned to the conditions prior to cold shock, a clear increase in plasma cortisol and glucose occurred in the cold-shock group.…”