Resveratrol Induces Expression of Metabolic and Antioxidant Machinery and Protects Tilapia under Cold Stress

Exposures to low ambient temperature require ectothermic fish to not only adjust their metabolic machinery but also to mount protective responses against oxidative stress. In this study, we tested whether diets supplemented with resveratrol (RSV), a naturally occurring polyphenol known to stimulate metabolic and protective responses in various animals, would be beneficial to tilapia (Oreochromis mossambicus) under hypothermic challenge. Feeding tilapia with RSV-supplemented diet promoted liver expression of sirtuins and their known targets, including metabolic/antioxidative enzymes. After exposure to 15 degrees C cold conditions for three days, the oxygen-nitrogen (O:N) ratio was decreased in the control-diet-fed tilapia but not in their RSV-fed counterparts. Moreover, at 27 degrees C, RSV-fed tilapia showed significantly higher prolonged swim speed compared with controls. RSV feeding produced no significant effect on upper and bottom layer preference between the control- and RSV-treated tilapia at either 27 degrees C or 15 degrees C. Together, these findings suggest that RSV stimulates beneficial metabolic/antioxidative adjustments in teleosts and may serve as a valuable feed supplement for tropical fish exposed to cold stress during winter.