Cardiorespiratory responses to graded hypoxia in the neotropical fish matrinxã (Brycon amazonicus) and traíra (Hoplias malabaricus) after waterborne or trophic exposure to inorganic mercury.

The growing Hg input in aquatic environments results in high accumulation of mercury in fish tissue and their consumers, which poses a serious risk to humans and ecosystems. The aim of this study was to evaluate the effects of the inorganic mercury exposure on cardiorespiratory responses in two species of neotropical fish ecologically distinct, matrinxã (Brycon amazonicus) and traíra (Hoplias malabaricus). Matrinxãs were exposed to a nominal and sublethal concentration of 0.

Cardio-respiratory function and oxidative stress biomarkers in Nile tilapia exposed to the organophosphate insecticide trichlorfon (NEGUVON).

The cardio-respiratory function, oxidative stress and fish antioxidants were analyzed in juvenile Nile tilapia exposed for 96 h to a sublethal trichlorfon (TRC-Neguvon, Bayer) concentration of 0.5 mg L(-1). The exposure to TRC induced oxidative stress in the heart, as manifested by the glutathione S-transferase depletion and hydroperoxide elevation, and was the most sensitive organ when compared to the liver and gills, in which the antioxidant mechanisms against TRC exposure were sufficient to remove reactive oxygen species (ROS), preventing the increase of lipid peroxidation.