Utilização de óleos essenciais de Lippia alba (erva-cidreira) e Aloysia triphylla (erva-Luiza) para Macrobrachium rosenbergii

Abstract

The use of essential oils has already been evaluated for several aquatic organisms and has shown positive effects in relation to productive performance, efficiency in the use of nutrients, increased growth rate, resistance to stress, immunity and protection against pathogens, in addition to standing out for being natural and safe substances for the environment and animals. In this thesis, the aim was to evaluate the response of the physiological, zootechnical and anesthetic parameters of the addition of the essential oils of Lippia alba (OELA) and Aloysia triphylla (OEAT) to Macrobrachium rosenbergii. Specifically, the thesis is subdivided into four chapters, beginning, the first chapter, by the bibliographic review where topics related to aquaculture in general and the use of essential oils in prawn farming are addressed, in addition to their importance in oxidative stress. In the second chapter, the use of L. alba essential oil (0.0 - control, 1.0 or 2.0 mL of OELA diet/kg; in triplicate, with 20 prawns/replica) was evaluated in the diet for juveniles of M. rosenbergii: its effects on antioxidant enzymes and growth parameters. In the third chapter, the use of A. triphylla essential oil was evaluated (0.0 - control, 1.0, 2.0 and 3.0 mL of OEAT/kg diet with five repetitions, with 20 prawns/replica), in the diet of M. rosenbergii juveniles: effects on zootechnical parameters. In the fourth chapter, we sought to understand the effect of the anesthetic potential of the essential oil of A. triphylla in postlarvae of M. rosenbergii, in which six concentrations of OEAT (in µL/L) were tested, in triplicate, with 10 animals/replica, named as follows: positive control (0), negative control (volume of ethanol (3600); corresponding to the highest concentration used to dilute the OE), 150, 225, 300 and 450, these concentrations were tested in two hardnesses of water (32 and 68 mg CaCO3/L). In the first experiment, OELA doses contributed to decrease lipid peroxidation. In addition, the dose of 2.0 mL of OELA/kg of diet contributed to increase the activities of antioxidant enzymes in the hepatopancreas. In the second experiment, the doses of OEAT added to the diet did not alter the parameters of zootechnical performance. Finally, in the third experiment, the effect of the anesthetic potential of OEAT was evaluated, and it was therefore observed that exposure to OE caused mortality in all concentrations used for the hardness of 32 mg CaCO3/L. Despite this, OE concentrations below 150 µL/L can be recommended for short exposure periods. The values found for CL10 and CL50 after 30 minutes of recovery were, respectively (in µL/L): 195.34 and 325.43. On the other hand, in animals kept at a hardness of 68 mg CaCO3/L, no mortality was observed in the tested OE concentrations. The OEAT concentration of 225 and 300 μL/L was effective in anesthetic induction for M. rosenbergii post-larvae in a hardness of 68 mg CaCO3.L-1, to avoid a possible toxic effect. Considering the biotic and abiotic factors involved in this thesis, it can be concluded that the use of 2.0 ml of OELA in the diet of M. rosenbergii directly contributes to an improvement in the enzymatic antioxidant activity and, possibly, indirectly in the immune and defense against pathogens. On the other hand, the doses of OEAT added to the diet do not have a negative effect on zootechnical performance, but research related to biochemical and physiological parameters needs to be carried out.