Dietary taurine intake affects growth and taurine synthesis regulation in golden pompano, Trachinotus ovatus (Linnaeus 1758)

Abstract

Taurine serves an important role in many species, including fish. The purpose of this study was to investigate the effects of varying dietary taurine levels on the growth, antioxidant capacity, and tissue deposition of taurine in golden pompano. In addition, the mechanism of taurine synthesis was studied via enzyme activity and gene expression of the following enzymes: cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), cysteine dioxygenase (CDO), cysteine sulfinic acid decarboxylase (CSAD), and 2-aminoethanethiol dioxygenase (ADO). Taurine concentrations of 1.3, 4.4, 7.4, 10.5 and 12.7 g kg−1 were added to the basic feed, hereafter labelled the T0, T1, T2, T3 and T4 diets, respectively. A control diet was supplemented with 1.3 g kg−1 taurine. Following 8 weeks of treatment, the results showed that the specific growth rate increased with the increase in dietary taurine content; the growth rate peaked at the 10.5 g kg−1 dietary taurine level (P < 0.05). The hepatosomatic index was significantly reduced as dietary taurine levels increased (P < 0.05). Crude protein and crude lipid in the body increased significantly with the intake of exogenous taurine (P < 0.05). The increase in dietary taurine significantly increased the total antioxidant capacity, as well as the superoxide dismutase, catalase, and glutathione peroxidase activities; however, the malondialdehyde concentration correspondingly decreased (P < 0.05). The taurine content in whole fish, liver, heart, eye, kidney, brain, muscle and gill significantly increased with the increase in dietary taurine (P < 0.05). The activity of CSE, CDO, CSAD and ADO decreased with the increase in dietary taurine (P < 0.05). Taurine intake had no significant impact on CBS activity (P > 0.05). The gene expression of CBS, CSE, CDO, CSAD and ADO exhibited a downward trend with an increase of taurine (P < 0.05). These results indicate that taurine plays an important role in the growth of golden pompano. Polynomial regression analysis revealed that the taurine requirements of golden pompano could be satisfied if the taurine content reached at least 10.0 g kg−1. In addition, taurine has a regulating effect on taurine synthesis in golden pompano.