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 Trachinotus ovatus 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 Trachinotus ovatus. The survival period and survival rate of Trachinotus ovatus 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 Trachinotus ovatus. 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.