The anti-stress effect of taurine in fish: Assessments based on repeat acute stress and animal individuality

A series of acute stressors can force the animal into a pathological condition and disease susceptibility in different individuals. Taurine has an important effect on relieving and reducing the animal anxiety. In order to know whether taurine has anti-stress effect on olive flounder (Paralichthys olivaceus) with bold and shy coping style, we demonstrate that, repeated acute stress suppress energy expenditure and manifest high behavioral plasticity. Interestingly, treatment with taurine attenuated stress in the divergent behavioral types: 1. Taurine reduced the stress response of flounders in terms of respiratory metabolism and spontaneous activity; 2. Taurine deactivated both of shy individuals "freeze-hide " and bold individuals "fight-flight " response during a threat encounter; 3. Treatment with taurine also significantly reduced the plasma epinephrine (EPI), norepinephrine (NE), adreno-cortico-tropic-hormone (ACTH) and cortisol, and the expression of corticotropin-releasing hormone (CRH), urotensin I (UI) and urotensin II (UII) in hypothalamus and caudal neurosecretory system (CNSS) during stress. Overall, our study demonstrates that taurine can effectively promote anti-stress ability and passivate stress response in flounder by modulating stress axis.