Dietary taurine enhances antioxidant and immune defenses to alleviate transport-induced stress in Culter alburnus
Transport induces acute physiological stress in fish, often resulting in oxidative damage and reduced survival. Taurine, a sulfur-containing amino acid with known antioxidant and immunomodulatory properties, may offer a protective strategy. Here, we evaluate the effects of dietary taurine supplementation on the growth performance, antioxidant capacity, and immune response of Culter alburnus under transport stress. Juvenile fish were fed diets containing 0 (control), 0.5, 1.0, 1.5, or 2.0 g/kg taurine for 8 weeks, followed by a 12 hour simulated transport. Taurine significantly improved growth performance and water quality parameters post-transport. Antioxidant enzyme activities, including catalase (CAT) and glutathione peroxidase (GSH-Px), were elevated in the highest-dose group (2.0 g/kg), while malondialdehyde (MDA) levels declined. Immune markers, such as acid phosphatase (ACP) and alkaline phosphatase (AKP), increased, whereas total nitric oxide synthase (T-NOS) activity decreased. Transcriptomic analysis revealed activation of the Toll-like receptor and cytokine-cytokine receptor interaction pathways, indicating enhanced immune and antioxidant gene expression. These findings demonstrate that taurine supplementation enhances physiological resilience to transport stress in C. alburnus, providing a mechanistic basis for its application in aquaculture.