Abstract
This study analyzed the chemical composition and anesthetic potential of essential oil (EO) of Nectandra megapotamica in fat snook (Centropomus parallelus). For the extraction of EO by hydrodistillation, leaves were separated in young (EO-Y) or old (EO-O), and the chemical composition of the EOs was determined by CG-MS. The anesthetic potential was assessed by the evaluation of induction and recovery time of anesthesia and stress response from anesthesia and transport. Three experiments were carried out: i) four different concentrations of each EO were tested to evaluate anesthesia induction and recovery time; ii) two concentrations of EO-O were tested for the evaluation of its effects on stress parameters (glucose, lactate, and Na+ and K+ plasma levels) caused by anesthesia; and iii) fish were transported in plastic bags, supplied with two concentrations of EO-O for the evaluation of water quality and mortality. All experiments were performed on fish acclimated to 0 and 33 ppt salinity. The main constituents of the Y and O-EOs were bicyclogermacrene (46.5/34.6%), α-pinene (26.8/26.2%), β-pinene (7.9/12.3%), and germacrene D (9.6/9.1%). Mild sedation was achieved at 30 °L L-1(1.3-3.2 min) and deep anesthesia at 150 °L L-1(5.6-8.0 min) with both EOs. The recovery time ranged from 1-10 min. The EO-O was not able to avoid the stress of anesthesia evidenced by elevated glucose and lactate plasma levels observed in all groups. Plasma levels of Na+ and K+ were not significantly affected by treatments. During transport, the use of EO-O did not prevent deterioration in water quality and the post-transport mortality. In conclusion, the EO of N. megapotamica has anesthetic activity in fat snook, but it was not able to prevent the stress of anesthesia and transport.
Highlights
Anesthetics are used in modern aquaculture management to minimize stress or physical damage caused by handling, transport, and more invasive procedures that may cause poor performance, immunosuppression, and increased mortality in fish (Gray et al, 2011)
The objective of the present study was to determine the anesthetic potential of the essential oils (EOs) of N. megapotamica evaluating the induction and recovery times from anesthesia as well as its effect on biochemical and osmoregulatory parameters related to stress of anesthesia and transport in fat snook, Centropomus parallelus
All fish recovered from anesthesia within 30 min and no mortality was registered in the course of the experiment
Summary
Anesthetics are used in modern aquaculture management to minimize stress or physical damage caused by handling, transport, and more invasive procedures that may cause poor performance, immunosuppression, and increased mortality in fish (Gray et al, 2011). Several studies using plant derivative compounds, such as essential oils (EOs) from Eugenia, Mentha, and Lippia species, have demonstrated that these natural products are effective for fish sedation and may have benefits over traditional methods, including lower cost and higher safety (Cunha et al, 2010a; Gonçalves et al, 2008; Palic et al, 2006). Previous pharmacological investigation using mice and rats have showed analgesic and anti-inflammatory activities for the bark hydroalcoholic extract of this species (da Silva et al, 2004). Studies have showed that the ethanolic extract from the trunk bark presents antioxidant and antimicrobial activities (Garcez et al, 2009), while for the leaf essential oil, literature describes anti-inflammatory and antitumor activities (Apel et al, 2006)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
