Potencial anestésico do óleo essencial de Ocimum basilicum em tilápia do nilo

Abstract

The objective of this work was to evaluate the time of anesthetic induction and recovery of Nile tilapia fingerling (Oreochromis niloticus) subjected to different concentrations of Ocimum basilicum essential oil. For this purpose, a total of 32 fry were used, with an average weight of 0.94 ± 0.39 g and an average total length of 3.56 ± 0.26 cm, acquired from a commercial fish farm. The fish were fed until apparent satiety three times a day with a commercial diet. After the acclimatization period, the juvenile pacu were evaluated regarding the induction and recovery time from anesthesia. The fish were transferred to three aquariums (8L) with water from the acclimatization tanks. The fish were exposed to the following treatments with different concentrations of O. basilicum essential oil: 100, 150, 200 and 250 mg L-1. To evaluate the anesthetic induction and recovery time, eight fish were used per concentration (4 fish x 2 replications per treatment). Ocimum basilicum essential oil induced stage IV anesthesia at all concentrations evaluated in less than 10 minutes. An increasing effect was observed, the higher the anesthetic concentration, the shorter the time for anesthetic induction (p<0.0001). Regarding the anesthetic recovery time, it was observed that as the anesthetic concentration increased, the time required for the animals to return from the anesthetic plane was greater, which took less than 5 minutes and had no deleterious effects on survival. With the results, it can be concluded that Ocimum basilicum essential oil is a safe and effective natural product in the anesthesia of Nile tilapia Oreochromis niloticus fingerlings, with the best anesthetic effect at a concentration of 200 mg L-1 of the essential oil.