Óleo essencial de Lippia alba como sedativo e anestésico em diversos animais aquáticos

Abstract

The use of anesthetics in aquaculture and research stations is a very important tool to minimize both the damage and the consequent stress caused by routine activities, as well mortality of the animals. This thesis is divided into three chapters, and aims to evaluate the use of essential oil of Lippia alba (EOL) as sedative and anesthetic in aquatic animals, analyzing its possible stressful effects. The chapter 1 consists in the assessment of the effects of EOL in the behavioral, metabolic and oxidative stress parameters in the mussel Perna perna. Two experiments were conducted, the first tested concentrations of 150, 300 and 450 μL L-1 for one hour at most. In the second experiment, the mussels were first exposed to an initial concentration of 100 μL L-1 EOL for 30 minutes and then more anesthetic was added to achieve the concentrations tested in the first experiment, for an additional 30 min. The sedation, anesthesia and recovery times were observed, as well glycogen, lactate, protein and glucose, and oxidative stress parameters (CAT, GST, LPO, PC and SOD) were analyzed in hemolymph, gills and gonads of animals, with and without recovery, following exposure to the anesthetic. The chapter 2, as in the previous chapter, evaluated the EOL efficiency in Echinometra lucunter (sea urchin), analyzing coelomic fluid, gonads and intestine of animals sampled with and without recovery after exposure, to analyze the metabolic (proteins and lipids) and oxidative stress parameters (TBARS, SOD and CAT). The chapter 3 verified the stress responses of sea bass (Dicentrarchus labrax). Firstly an ideal concentration for sedation was elected and in a second experiment fish were exposed to a stressful situation (chase to capture) with different combinations of treatments and sampling times. Plasma and liver of the animals were collected to analyze the physiological changes as cortisol, glucose, lactate, triglycerides, protein and glycogen, as well as the enzymatic activities in the liver (GPtotal, HK, BPF, G6PDH, PK, G3PDH, GDH, GPT and GOT). The exposure to EOL did not cause mortality and presented satisfactory sedative and/or anesthetic effect in the aquatic animal species tested, except mussels because they closed the shell and reduced filtration as a defensive behavior and well-being when exposed to any different substance detected in the water. Thus, the EOL has a favorable effect in all species tested, because it led to improvement in the response of antioxidant defenses and reduced oxidative stress, being a good alternative as sedative and/or anesthetic in procedures for aquaculture and research stations.