Sedative and anesthetic potential of the essential oil and hydrolate from the fruit of Protium heptaphyllum and their isolated compounds in Colossoma macropomum juveniles

Abstract This study aimed to evaluate the sedative and anesthetic potential of the essential oil (PHEO) and hydrolate (PHH) from the fruit of Protium heptaphyllum and the isolated compounds (IC) of PHEO in tambaqui (Colossoma macropomum) juveniles. Fish were placed in aquaria with different concentrations of PHEO, PHH or IC (sabinene, terpinen-04-ol, γ-terpinene and α-pinene) to evaluate sedative and anesthetic efficacy. In another experiment, fish were transported for 22 h with 10% anesthetic concentrations added to the water of transport. No similarities regarding the major compounds of PHEO and PHH were observed. No mortality was observed during the experiments, and PHH did not show any sedative or anesthetic effect. PHEO induced sedation at 250 mg L−1 and deep anesthesia at 500, 750 and 1000 mg L−1. The recovery time increased with increasing concentration of PHEO. There was a significant difference in the time to induce deep anesthesia between PHEO and IC. Water conductivity and mucous cell density were lower in the transport with 50 mg L−1 PHEO. Tambaqui transported with 50 mg L−1 PHEO and 11.6, 17.4, and 23.2 mg L−1 terpinen-04-ol presented lower net whole body K+ and Cl− effluxes. PHEO is an alternative as sedative and anesthetic for tambaqui juveniles, and the concentration of 500 mg L−1 was the best for deep anesthesia. The use of 50 mg L−1 PHEO was effective for the transport of this species because it reduced net K+ and Cl− effluxes and did not stimulate proliferation mucous cells.