02252naa a2200253 a 450000100080000000500110000800800410001910000210006024501630008126000090024452015140025365000190176765000200178665000100180665000140181665000130183065000240184365000130186765300190188070000180189970000190191770000210193677300410195720432342017-03-14       2016    bl uuuu     u00u1 u    #d1 aMALHEIROS, D. F.  aToxicity of the essential oil of Mentha piperita in Arapaima gigas (pirarucu) and antiparasitic effects on Dawestrema spp. (Monogenea).h[electronic resource]  c2016  aThis study evaluated the in vitro and in vivo effects of the essential oil of Mentha piperita on monogeneans and its toxicity for Arapaima gigas. For the in vitro assay, gills of A. gigas naturally infected by Dawestrema cycloancistrium and Dawestrema cycloancistrioideswere exposed to 0, 80, 160 and 320 mgL?1 of M. piperita, which demonstrated anti-helminthic activity. In the toxicity test, A. gigas fingerlings were exposed to 0, 20, 40, 80, 100, 130 and  160 mg L?1 of M. piperita to determine the lethal concentration (LC50-4 h), which was found to be 38 mg/L. Fish that had been exposed to 80, 100, 130 and 160 mg L?1 presented epithelial elevations, fusion of the secondary lamellae, hypertrophy and aneurism. Necrosis was only observed at a concentration of 160 mg L?1 of M. piperita. The in vitro results demonstrated that the anti-helminthic activity of M. piperita against Dawestrema spp.was dose dependent. However, bathswith 40 mg L?1 of essential oil ofM. piperita were not effective against monogeneans in the gills of A. gigas. Therefore, since this anti-parasitic substance was in vitro effective and the concentrations used in the baths were not efficient and caused tissue alterations in the gills of the fish, other therapeutic strategies should be tested in order to increase the efficacy of this phytotherapeutic substance and reduce its toxicity for A. gigas. Finally, this study investigated the efficacy of M. piperita essential oil against parasites of A. gigas, for the first time.  aArapaima gigas  afreshwater fish  agills  aMonogenea  atoxicity  aPeixe de água doce  aPirarucu  aHerbal therapy1 aMACIEL, P. O.1 aVIDEIRA, M. N.1 aTAVARES-DIAS, M.  tAquaculturegv. 455, p. 81-86, 2016.