Dietary L-tryptophan modulates growth and immuno-metabolic status ofLabeo rohitajuveniles exposed to nitrite

Abstract

Effect of nitrite exposure on growth and immunometabolic responses of Labeo rohita fed L-tryptophan (TRP) was studied. Fish previously fed normal and elevated levels of tryptophan for 60 days were exposed to nitrite (2.0 mg L À1 ) for another 45 days with same feeding regime. There were four treatment groups, viz., TRP 0 -N (control), TRP 0 +N, TRP 0.75 +N (0.75% supplemental tryptophan in the diet) and TRP 1.5 +N (1.5% supplemental tryptophan in the diet). Highest weight gain% and SGR were observed in control and lowest in TRP 0 +N. Dietary supplementation of elevated levels of tryptophan augmented weight gain% and SGR. Nitrite exposed groups recorded higher catalase, SOD, LDH, AST and ALT activities compared with control. However, activities reduced with additional levels of tryptophan supplementation. Nitrite exposure reduced WBC count, total protein, albumin, globulin and lysozyme activity compared with unexposed group but groups which were fed additional amounts of tryptophan restored total protein, albumin and globulin similar to TRP 0 -N. In conclusion, nitrite exposure had adversely affected growth, increased activities of LDH, AST, ALT, catalase, but decreased WBC, serum protein, lysozyme and acetylcholine esterase activity of L. rohita. Normal requirement of tryptophan was unable to combat nitrite stress. However, dietary fortification with tryptophan (minimum 0.75% of diet + normal requirement) found effective in combating nitrite induced stress.

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

“…However, it appeared to provide some protection against the loss of activity that was seen in the control group following confinement stress. The effects of dietary supplementation with tryptophan on humoral non-specific immune response in fish were studied in L. rohita (Ciji et al, 2013b). These authors reported that tryptophan supplementation reduced declines in white blood cell counts, lysozyme activity and globulin levels in fish exposed to an immunosuppressive condition (elevated water nitrite concentration).…”

“…Serotonin stimulates lymphoproliferation in Lepomis macrochirus and Oncorhynchus mykiss (Ferriere et al, 1996;Ferriere et al, 1999;Duffy-Whritenour and Zelikoff, 2008). Also, dietary tryptophan mitigated a decrease in white blood cell count, serum globulin level and serum lysozyme activity under an immunosuppressive condition (nitrite exposure) in L. rohita (Ciji et al, 2013b). Limited data on this topic encourages further studies on fish immunomodulation using exogenous tryptophan.…”

“…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).…”

Physiological roles of tryptophan in teleosts: current knowledge and perspectives for future studies

“…(2013a) and Ciji et al . () showed that L. rohita fed on diets containing tryptophan levels of 3.05–5.17% of dietary protein have significantly improved weight gain compared to control fish (fed with diet containing 0.99% tryptophan). In Cirrhinus mrigala , dietary tryptophan levels of 0.95 and 1.2% of dietary protein were reported as optimum dietary tryptophan levels for optimum growth of the fish.…”

“…(2013a) and Ciji et al . () reported that growth performance of L. rohita exposed to stressful conditions and water pollution improves when fed diets containing 3.05–5.17% tryptophan (% of dietary protein) compared to that containing 0.99% tryptophan (discussed below).…”