Tese
Óleos essenciais de plantas como alternativa aos fármacos convencionais na produção de peixes
Autor
Sutili, Fernando Jonas
Institución
Resumen
The essential oils (EO) obtained from plants are a major source of new molecules and have
been studied as alternatives to conventional drugs in the treatment of diseases, as immune
response modulators and as new growth promoters in fish. The aim of this study was to
evaluate the potential use of different EOs from the plants Ocimum americanum (OA),
Ocimum gratissimum (OG), Hesperozygis ringens (HR), Cymbopogon flexuosus (CF) and
Melaleuca alternifolia (MA) in the control of diseases, as immunomodulators and as growth
promoters in the fish species Rhamdia quelen and Sciaenops ocellatus. The EOs from OA,
OG and HR showed weak to moderate activity in vitro against the bacterium A. hydrophila,
however, they significantly inhibited the hemolytic activity caused by this bacterium in fish
erythrocytes. The EO of OA also presented antiparasitic activity in vitro and in vivo against
the monogenean parasite Gyrodactylus sp. The EOs from OA, CF and MA were capable of
triggering (in vitro) superoxide anion (O2
-) production in S. ocellatus leukocytes (head-kidney
macrophages and/or blood leukocytes). The use of the OA and HR EOs in vivo promoted
survival of R. quelen infected with A. hydrophila, as well as showed potential as modulator of
the innate immune response in both studied fish species: after exposure through baths (R.
quelen) or added to the diet (OA in S. ocellatus). Herbal products such as EOs appear as safe
alternatives in fish production because they are natural and biodegradable products,
contributing to the reduced use of conventional drugs and pesticides.