Lippia alba essential oil as anesthetic for tambaqui

The study evaluated the anesthetic activity of Lippia alba essential oil (EO) in tambaqui (Colossoma macropomum). For this, two assays were realized. The first experiment determined the time to induce tambaqui anesthesia using L. alba EO at 20, 50, 100, 200 and 300 mg L−1. In the second were evaluated the biochemical response of fish to the stress caused by handling and anesthesia with 0, 50 and 100 mg L−1 of L. alba EO. In tambaquis the anesthetic action of L. alba EO was obtained using doses of 50 to 300 mg L−1. Doses from 200 to 300 mg L−1 caused the faster anesthesia (<4 min), whereas 100 mg L−1 induced anesthesia in <10 min. Glucose, lactate and ammonia levels increased immediately after 10 min of fish anesthesia with 50 and 100 mg L−1 of L. alba EO and handling stress, but they recovery from the procedures after 24 h. The results indicated that L. alba EO can be used to induced faster anesthesia in tambaquis (200-300 mg L−1), but the tambaqui exposure to doses of 50 and 100 mg L−1 of L. alba EO for 10 min did not prevent the effects of handling stress.