Effects of dietary taurine on growth, taurine metabolism and Vibrio crassostreae resistance in juvenile clam Ruditapes philippinarum

Abstract

Taurine serves an important role in all aquatic animals. The purpose of this experiment was to investigate the effects of exogenous taurine on growth, endogenous taurine metabolism, and Vibrio crassostreae resistance in juvenile clam Ruditapes philippinarum. Microencapsulated taurine concentrations of 0, 0.75, 1.5, 3 and 6 mg/g clam wet weight were designated as the T0, T0.75, T1.5, T3 and T6 groups. After 2 weeks of feeding, the results demonstrated that exogenous taurine did not promote the growth of clams (P > 0.05). The taurine content of clams was increased significantly with the increase of exogenous taurine content (P < 0.05). The gene expression of taurine transporter (TauT) was significantly elevated in the T3 and T6 groups compared to the T0 group (P < 0.05). With the addition of exogenous taurine, mRNA expressions of cysteine sulfinic acid decarboxylase (CSAD), 2-aminoethylsulfide dioxygenase (ADO), cysteine dioxygenase (CDO), cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and serine dehydratase (SDH) were suppressed (P < 0.05). The survival rate of clams challenged with Vibrio crassostreae was significantly higher in the T0.75 group compared to the T0 group on the fifth day (P < 0.05). Additionally, the activities of antioxidant enzymes and lysozyme were significantly elevated, immune-related and anti-inflammatory factor genes were upregulated, while pro-inflammatory factor genes were downregulated in the T0.75 group compared to the T0 group (P < 0.05). Dietary taurine supplementation regulates endogenous taurine metabolism and exhibits potential anti-Vibrio effect in clam R. philippinarum.