Efficiency of Cinnamomum camphora var. linaloofera Fujita essential oil, MS-222, and linalool on anesthesia and transportation of spotted seabass (Lateolabrax maculatus).

Plant-based essential oils have been considered to be used as fish anesthetics and as suitable alternatives to synthetic anesthetics. In this study, we evaluated the effect of Cinnamomum camphora var. linaloofera Fujita essential oil (CFEO), MS-222 and linalool on anesthetic induction and recovery of spotted seabass, Lateolabrax maculatus, and verified their sedative effects during simulated transportation. A total of 198 live spotted seabass samples were subjected to various concentrations of MS-222, CFEO, and linalool: 10, 20, 30, 50, 100, 150, and 200 mg L^-1, individually, to evaluate the anesthetic induction time. MS-222, CFEO, and linalool all showed a deep sedation in spotted seabass at 20 mg L^-1. The minimum concentration required to achieve profound anesthesia in spotted seabass was found to be 50 mg L^-1 MS-222, 100 mg L^-1 CFEO, and 50 mg L^-1 linalool, respectively. In addition, 120 healthy spotted seabass (400 g ± 3.5 g) were randomly divided into four groups, which were tranquilized by 20 mg L^-1 CFEO, linalool, and MS-222, and the control fish were kept in clean seawater without anesthetics and essential oils. Then, the spotted seabass was simulated to be transported in a vibrating conveyor under 100 rpm at 12 °C for 24 h. The results showed that the fish transported with MS-222 and CFEO showed lower expressions in cytokine (tumor necrosis factor-α, interleukin-6, and interleukin-1 beta) compared to fish transported with linalool. Sedation with linalool reduced oxidative stress (higher superoxide dismutase, catalase, and glutathione peroxidase activities) in transport compared to the control but did not prevent changes in the activities of heat shock protein. In general, the efficacy of CFEO in anesthetizing and sedating spotted seabass and mitigating transport stress was as good as or better than that of MS-222, demonstrating it has the potential to be used as a new and natural sedation for spotted seabass during transport.