The anesthetic efficacy of eugenol and the essential oils of Lippia alba and Aloysia triphylla in post-larvae and sub-adults of Litopenaeus vannamei (Crustacea, Penaeidae)

Abstract

The aim of this study was to evaluate the anesthesia induction and recovery times of sub-adult and post-larvae white shrimp (Litopenaeus vannamei) that were treated with eugenol and the essential oils (EOs) from Lippia alba and Aloysia triphylla. Oxidative stress parameters in the hemolymph of this species were also analyzed. The concentrations of eugenol, A. triphylla EO and L. alba EO recommended for anesthesia were 200, 300 and 750μLL−1 for sub-adults and 175, 300 and 500μLL−1 for post-larvae, respectively. The concentrations studied during the transport of sub-adults were between 20 and 50μLL−1 eugenol, 20–30μLL−1A. triphylla EO and 50μLL−1L. alba EO. For post-larvae, the optimal concentrations for transport were 20μLL−1 eugenol and between 20 and 50μLL−1A. triphylla EO. The white shrimp sub-adults that were exposed to A. triphylla EO (20μLL−1) showed increases in their total antioxidant capacities (150%), catalase (70%) and glutathione-S-transferase (615%) activity after 6h. L. alba EO (50μLL−1) and eugenol (20μLL−1) also increased GST activity (1292 and 1315%) after 6h, and eugenol (20μLL−1) decreased the total antioxidant capacity (100%). Moreover, concentrations above 30μLL−1 for the EOs of A. triphylla and L. alba and 20μLL−1 eugenol were effective at inducing anesthesia and improving the antioxidant system against reactive oxygen species (ROS) after 6h.