Dietary tryptophan changes serum stress markers, enzyme activity, and ions concentration of wild common carp Cyprinus carpio exposed to ambient copper

Abstract

Effect of dietary tryptophan (TRP) on copper toxicity was investigated in common carp, Cyprinus carpio. Fish were randomly distributed into two triplicate treatments (control and TRP) and fed control (TRP = 3.1 g kg(-1)) or TRP (TRP = 8.1 g kg(-1)) diets over a 2-week period. Then, both treatments were subjected to 10 mg l(-1) copper sulfate over a 7-day period. Mortality and serum cortisol, glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), sodium, potassium, and chloride levels were recorded at 0, 24, 72, 120, and 168 h post-copper exposure. There was no mortality in the TRP group, whereas the control group mortality was started at 120 h post-copper exposure (21.7 ± 7.6 %) and reached 61.7 ± 10.4 % at the end of the experiment. Cortisol, glucose, ALT, and AST levels significantly (P < 0.05) increased after copper exposure in both groups; however, the control group showed significantly higher levels than the TRP group. In both groups, sodium decreased after copper exposure and did not return to the pre-exposure values. Potassium levels significantly increased 24 h post-copper exposure in both groups and remained significantly elevated in the control group at 72 h, when fell to the pre-exposure values in the TRP group. No significant changes were observed in the chloride levels in any groups. It is concluded that dietary TRP is capable to increase common carp tolerance to copper toxicity via mitigating copper-induced stress rather than restoring gill dysfunction and hydromineral imbalance.

Serum cortisol, glucose, thyroid hormones' and non-specific immune responses of Persian sturgeon, Acipenser persicus to exogenous tryptophan and acute stress

“…In Cyprinus carpio, feeding 0.5% exogenous tryptophan elevated serum cortisol levels after 5 and 15 days (Hoseini and Hosseini, 2010), a result that was not repeated in the other studies on same species and 0.33-0.99% exogenous tryptophan levels (Hoseini et al, 2012;Hosseini and Hoseini, 2013). In O. mykiss, feeding 0.36% exogenous tryptophan increased plasma cortisol after 3 and 7 days, but not 28 days (Lepage et al, 2002;Lepage et al, 2003).…”

“…Tryptophan affects Adrenocorticotropic hormone (ACTH) and cortisol levels, and circulating cortisol is known as the most common indicator of stress in fish, which has been used to evaluate stress-mitigating effects of tryptophan in fish (Lepage et al, 2002;Lepage et al, 2003;Hoseini and Hosseini, 2010;Hoseini et al, 2012;Hosseini and Hoseini, 2013). Effects of tryptophan on fish stress response are situation-dependent.…”

“…Dietary tryptophan supplementation (0.68-2.72% of diet) has been found to inhibit chronicstress effects on blood cortisol, glucose and immune response in Labeo rohita and Cirrhinus mrigala (Tejpal et al, 2009;Akhtar et al, 2013;Ciji et al, 2013a;Ciji et al, 2013b). The effects of tryptophan on basal and post-stress cortisol show great variability in different fish species; as dietary tryptophan may increase (Lepage et al, 2002;Lepage et al, 2003;Hoseini and Hosseini, 2010) or decrease (Basic et al, 2013a) basal cortisol levels or have no effect on it (Herrero et al, 2007;Hoseini et al, 2012;Wolkers et al, 2012;Basic et al, 2013a;Hosseini and Hoseini, 2013;Martins et al, 2013). In addition, tryptophan may suppress (Lepage et al, 2002;Lepage et al, 2003;Herrero et al, 2007;Hoseini and Hosseini, 2010;Hoseini et al, 2012;Basic et al, 2013b;Hosseini and Hoseini, 2013) or have no effect on post-stress cortisol response (Wolkers et al, 2012;Basic et al, 2013a;Martins et al, 2013).…”

“…The effects of tryptophan on basal and post-stress cortisol show great variability in different fish species; as dietary tryptophan may increase (Lepage et al, 2002;Lepage et al, 2003;Hoseini and Hosseini, 2010) or decrease (Basic et al, 2013a) basal cortisol levels or have no effect on it (Herrero et al, 2007;Hoseini et al, 2012;Wolkers et al, 2012;Basic et al, 2013a;Hosseini and Hoseini, 2013;Martins et al, 2013). In addition, tryptophan may suppress (Lepage et al, 2002;Lepage et al, 2003;Herrero et al, 2007;Hoseini and Hosseini, 2010;Hoseini et al, 2012;Basic et al, 2013b;Hosseini and Hoseini, 2013) or have no effect on post-stress cortisol response (Wolkers et al, 2012;Basic et al, 2013a;Martins et al, 2013). The effects of dietary tryptophan on physiological response of fish were found to be dependent on tryptophan levels, feeding duration and nature of the stress (Lepage et al, 2002;Lepage et al, 2003;Hoseini and Hosseini, 2010;Hoseini et al, 2012;Hosseini and Hoseini, 2013).…”

“…In addition, tryptophan may suppress (Lepage et al, 2002;Lepage et al, 2003;Herrero et al, 2007;Hoseini and Hosseini, 2010;Hoseini et al, 2012;Basic et al, 2013b;Hosseini and Hoseini, 2013) or have no effect on post-stress cortisol response (Wolkers et al, 2012;Basic et al, 2013a;Martins et al, 2013). The effects of dietary tryptophan on physiological response of fish were found to be dependent on tryptophan levels, feeding duration and nature of the stress (Lepage et al, 2002;Lepage et al, 2003;Hoseini and Hosseini, 2010;Hoseini et al, 2012;Hosseini and Hoseini, 2013).…”