Effects of food deprivation and handling stress on head kidney 17α-hydroxyprogesterone 21-hydroxylase activity, plasma cortisol and the activities of liver detoxification enzymes in rainbow trout

The effects of diet composition and ration on biotransformation enzymes and stress parameters in rainbow trout, Oncorhynchus mykiss

“…Although no effects of dietary nutrient content or ration size were observed in this study, other studies have demonstrated that both dietary nutrient content and dietary quantity may have significant effects on an animal's stress response (Barton et al, 1988;Farbridge and Leatherland, 1992) and on detoxification ability (Ankley et al, 1989, Vigano et al, 1993Blom et al, 2000). However, results of these studies have provided equivocal results to the degree of the effects and demonstrated that more research is needed in this area.…”

“…Buhler and Rasmusson (1968) reported no change in hepatic cytochrome P450 activity of rainbow trout after 8 weeks of starvation, while Blom et al (2000) reported significantly lower EROD, GST and GR activities after just 7 weeks of starvation. These findings have lead researchers to suggest that some forms of biotransformation enzymes may be decreased by starvation while other, enzymes may maintain, or even increase activity levels (Andersson et al, 1985a;Blom et al, 2000). Moreover, Andersson et al (1 985a) reported that while activity levels of 7-ethoxycoumarin-0-deethylase (ECOD), EROD, UDP-GT and AHH were unaffected by 6…”

“…Basal plasma cortisol levels in food deprived teleosts have been found to increase to levels approximately 2000 % higher than those found in fed fish after 21 days (Blom et al, 2000), decrease to 20 % of the level found in fed fish after 20 days (Barton et at., 1988) and have levels comparable to fed fish following six weeks (Farbridge and Leatherland, 1992) and 4 weeks (Vijayan and Moon, 1992) of food deprivation, thereby suggesting a complicated relationship between food deprivation and its perception as a stressor. However, in all of these studies, both the starved and fed fish were able to mount cortisol stress responses of similar magnitude thereby demonstrating that the cortisol response was not inhibited by food deprivation.…”

“…Several studies focussing on diet restriction and stress in fish have been published, however, variable effects of starvation in teleosts on the most commonly cited indicators of stress, namely plasma cortisol and glucose concentrations, have been reported (Barton et al, 1988;Farbridge and Leatherland, 1992;Vijayan and Moon, 1992;Blom et al, 2000). Basal plasma cortisol levels in food deprived teleosts have been found to increase to levels approximately 2000 % higher than those found in fed fish after 21 days (Blom et al, 2000), decrease to 20 % of the level found in fed fish after 20 days (Barton et at., 1988) and have levels comparable to fed fish following six weeks (Farbridge and Leatherland, 1992) and 4 weeks (Vijayan and Moon, 1992) of food deprivation, thereby suggesting a complicated relationship between food deprivation and its perception as a stressor.…”

“…The effects of depriving teleosts of food for periods between 15 days and 12 weeks on their biotransformation enzyme abilities have produced varying results (Buhler and Rasmusson, 1968;Andersson et at., 1985a;Vigano et at., 1993;Wall and Crivello, 1999;Blom et al, 2000). After two weeks of starvation, juvenile rainbow trout biotransformation enzymes including, hepatic 7-ethoxyresorufin-0-deethylase (EROD), glutathione S-transferase (GST) and benzo(a)pyrene hydroxylase (AHH) activities were maintained while UDP glucuronyltransferase (UDP-GT), and glutathione reductase (GR) activities were significantly decreased and cytochrome P450 activity was increased when compared to fish fed ad libitum (Vigano et al, 1993).…”