Dietary Supplementation With CoQ10 and Sel‐Plex Mitigates the Effects of Elevated Water Temperature on Performance, Digestive Physiology, Immune Competence, and Antioxidant Balance in Rainbow Trout

Background/Aims: ) under thermal stress, measured using real-time quantitative PCR (RT-qPCR) with β-actin as the reference gene. Methods: were assessed. Results: Elevated temperature significantly reduced growth, feed efficiency, and immune status. Dietary supplementation with CoQ10 or O-Se improved hepatic antioxidant capacity, digestive enzyme activity, and innate immunity, with the greatest effects observed when both supplements were combined. Cosupplementation also mitigated heat-induced upregulation of HSP70-α and IL-1β and reduced liver malondialdehyde (MDA) levels. Conclusion: Combined dietary CoQ10 and O-Se supplementation alleviate the adverse effects of elevated water temperatures on rainbow trout by enhancing growth, physiological performance, antioxidant defenses, and immune responses.