Óleos essenciais e eugenol como anestésico para Serrasalmus rhombeus

Abstract

This study evaluated the periods of time of anesthetic induction and recovery of Serrasalmus rhombeus exposed to essential oils (EOs) of Aloysia triphylla and Lippia alba and eugenol, as well as if these anesthetics can be used for transport of this species, through analysis of swimming behavior. Fish were placed in aquaria containing different concentrations of A. triphylla EO or L. alba EO or eugenol, and posteriorly were transferred to aquaria containing only water to evaluate the recovery time. In the second experiment, behavior was analyzed during exposure to A. triphylla EO, L. alba EO or eugenol at 5 or 10 µL L-1. The evaluations were carried out at 0, 1, 5, 10 and 15 min of exposure. Fish exposed to 150, 200 and 50 µL L-1 of A. triphylla EO, L. alba EO and eugenol, respectively, showed anesthetic induction time lower than 3 min and recovery time lower than 10 min. Concentrations of 50 µL L-1 of both EOs and 25 µL L-1 eugenol caused only sedation. Exposure to 5 and 10 µL L-1 EOs and eugenol decreased fish swimming time. Both EOs and eugenol were effective for anesthesia and can be used for transport of S. rhombeus.

Stress-reducing and anesthetic effects of the essential oils of Aloysia triphylla and Lippia alba on Serrasalmus eigenmanni (Characiformes: Serrasalmidae)

“…The more efficient concentration for rapid deep anesthesia in S. eigenmanni was 100 µL L -1 A. triphylla EO, with an induction time of 266 s and a recovery time of 110 s; increasing the concentration to 150 µL L -1 did not reduce the time to reach deep anesthesia. The recommended concentration for deep anesthesia in both the albino and gray strains of R. quelen (2.6-3.0 g, 24 ºC, pH 7.0) and in C. parallelus (2.7 g, 30 ppt seawater, 23 ºC) is 200 µL L -1 with the same EO , while for S. rhombeus (110.9 g, 30 ºC, pH 5.0), it is 150 µL L -1 (Almeida et al, 2018); these species need a concentration higher than that required for the deep anesthesia of S. eigenmanni. In the case of L. alba EO, the best concentration to induce deep anesthesia in S. eigenmanni was also 100 µL L -1 , with induction and recovery times of 236 s and 242 s, respectively.…”

“…11169) was deposited in the herbarium of the Biology Department. The EO extraction and analysis was made as described previously by Almeida et al (2018). The main compounds of the EO of A. triphylla are geranial (24.3%), limonene (21.7%) and ciscarveol (Z-carveol) (18.5%) and the main compounds of the EO of L. alba are linalool (66.3%) and eucalyptol (10.6%) (Almeida et al, 2018).…”

“…The fish were transferred individually to aquaria containing 5 L (30 ± 0.81 °C, pH 5.1 ± 0.09) of water with the L. alba or A. triphylla EOs in the 25 -200 μL L -1 concentration range, first diluted in ethanol at a proportion of 1:10. These concentrations were chosen based on a previous study with these EOs in S. rhombeus (Almeida et al, 2018). The time for anesthesia induction was evaluated according to Small (2003): stage I corresponds to sedation, when the reactivity to external stimuli is decreased; stage II involves the partial loss of equilibrium and erratic swimming, and stage III involves the total loss of equilibrium and the cessation of locomotion.…”

“…These concentrations were chosen based on the study of Almeida et al (2018) with a related species, S. rhombeus. Three fish per aquaria were used for each concentration (three replicates for each concentration).…”

“…Nevertheless, anesthesia with L. alba EO increased plasma cortisol of juvenile meagre, Argyrosomus regius (Cárdenas et al, 2016), indicating that the effect of a given EO may be species-specific. Almeida et al (2018) demonstrated the anesthetic and sedative efficacy of A. triphylla and L. alba EOs in Serrasalmus rhombeus (Linnaeus, 1766), an Amazonian fish living in the blackwaters of the Negro River, but did not evaluate whether these EOs prevent stress damage, such as ionoregulatory and blood disturbances, when applied in blackwaters.…”