Mitigating Effect of Taurine Combined with Corona Dormancy on Oxidative Stress in Trachinotus ovatus Under Low-Temperature Stress

The purpose of the present work was to establish the transportation conditions for keeping <i>Trachinotus ovatus</i> alive by means of corona-induced dormancy in combination with taurine. It also investigated the synergistic regulatory effects on oxidative stress mitigation and immune function during low-temperature conditions and clarified the underlying mechanism. The dormancy pretreatment induced by pulsed direct current could reduce the accumulation of reactive oxygen species in fish under hypothermal and water-restricted conditions and significantly enhance the environmental adaptability of <i>Trachinotus ovatus</i>. The survival period and survival rate of <i>Trachinotus ovatus</i> were significantly increased when combined with taurine at a concentration of 70 mg/L, and the activities of enzymes related to oxidative stress also increased significantly, including catalase, superoxide dismutase (SOD), glutathione S-transferase, and so on. The underlying mechanism involved the upregulation of mRNA expression in the Nrf2/Keap1 pathway components. Furthermore, taurine supplementation was found to bolster the immune function of <i>Trachinotus ovatus</i>. Histological examinations revealed that taurine exerted protective effects on the ultrastructural integrity of the liver and gills, which were susceptible to stress-induced damage during transportation. Altogether, the concerted action of corona dormancy and taurine significantly mitigated the stress responses and tissue injuries of fish during low-temperature live transportation, thereby providing a mechanistic basis for the enhancement of live fish transportation techniques.