Aquaculture practices include several procedures as capture, handling and transport, which cause stress in fish. Anesthetics or sedative substances have been used to reduce this stress. The aim of this study was to evaluate the effects of essential oil of Myrcia sylvatica (EOMS) in the water on stress system activation in the silver catfish Rhamdia quelen summited to transport. Fish were captured in the production ponds and transferred to a 250-L tanks (density of 54 kg/m3). After 24 hours, 10 fish were caught, euthanized by section of the spinal cord and sampled (basal group). The remaining fish were placed in plastic bags containing 5 L of water (density of 150 kg/m3) with different doses of EOMS (0, 25 or 35 μL/L diluted in 315 μL/L ethanol), in triplicate, and transported for 6 h. After transportation, 10 animals of each group were captured, euthanized and sampled. Cortisol and glucose levels in plasma, as well as hypothalamic corticotrophin-releasing hormone (CRH) and pituitary proopiomelanocortin (POMC) “a” and “b” mRNA expressions were determined. Cortisol levels and CRH expression enhanced after 24h of handling, decreasing during the transport with addition of EOMS. Expression of POMCa was higher in fish transported with 25 μL/L respect to the rest of groups. Therefore, it is suggested the use of EOMS for transporting fish in order to avoid the stress associated with this procedure.

Trabajo presentado en el 10º Congreso de la Asociación Ibérica de Endocrinología Comparada, celebrado en Castellón del 23 al 25 de septiembre de 2015.

Financial Support: FAPERGS/PRONEX, CAPES, CNPq.

Peer reviewed