Óleos essenciais alteram parâmetros comportamentais e bioquímicos em diferentes espécies de crustáceos?

Abstract

Crustaceans integrate essential ecosystem functions in the enviroment, acting from primary consumers to predators in aquatic trophic networks. Furthermore, many decapod crustaceans are important economic and social resources. However, these organisms are continually exposed to different stressors in the natural environment and captivity, involving, above all, variations in water quality parameters and inadequate management. Stress responses demand high energy expenditure and induce a cascade of behavioral events, neuroendocrine factors, and immunological mechanisms. In this way, behavioral and physiological observations provide a complete understanding of the homeostatic disturbances caused in the body by stressors. Recently, essential oils (EOs) have been reported as alternatives for handling and reducing stress in crustaceans. Therefore, it is necessary to investigate the sedative and anesthetic potential of different EOs, as well as to analyze their effects on behavioral and biochemical parameters in crustacean species, before recommending them as safe anesthetics. We found that EOs from Lippia alba (EOLA) and Cymbopogon citratus (EOC) were effective as anesthetics for the shrimps Farfantepenaeus paulensis and Litopenaeus vannamei, respectively. On the other hand, the EOs of Ocimum gratissimum (EOOG) and Origanum majorana (EOO) were not efficient for these species. Based on these results, we investigated the effects of EOC on the behavioral and biochemical activity of L. vannamei during an exposure period of 6h. In this experiment, we found that the concentration of 10 μL L-1 of EOC improved the antioxidant response without compromising the swimming behavior. Subsequently, we investigated the potential of EOLA and linalool (major compound) in reducing stress and oxidative damage in female and male L. vannamei during ocular peduncle ablation and spermatophore extrusion procedures, respectively. Antioxidant responses varied significantly between the sexes. However, EOs generated a protective effect and prevented lipid oxidation. The biochemical parameters analyzed in the two studies were: total antioxidant capacity against peroxyl radicals, reduced glutathione), sulfhydryl groups associated with proteins, and lipid peroxidation in the gills, hepatopancreas, and muscle. The EOs have also demonstrated success in inducing sedation and anesthesia of the amphipod Hyallela bonariensis. Among the EOs and their major compounds, that of Aloysia triphylla (EOAT) and linalool obtained better results. Furthermore, EOAT reduced the locomotion activity of H. bonariensis, but without compromising its natural behavior. Thus, we can conclude that EOs can be indicated as anesthetics for different species of crustaceans. However, the same EO can present different responses between species, demonstrating the need for previous studies to ensure its successful application.