Abstract

VASQUEZ, Rosa; BASTARDO, Asmine  and  MUNDARAIN, Inés K. Test of acute toxicity CL50-96h with cadmium acetate and hematological parameters in the farmed hybrid Colossoma macropomum x Piaractus brachypomus. Zootecnia Trop. [online]. 2005, vol.23, n.3, pp.247-257. ISSN 0798-7269.

The mean lethal concentration of cadmium was determined in alevines of cachamoto (Colossoma macropomum x Piaractus brachypomus) using cadmium acetate in acute toxicity tests based on static bioassays of 96 h (LC50-96h). The main short time effects of the pollutant were evaluated on the structure and on some hematological parameters of these fish. Animals had a mean weight of 4 g and standard length of 9 cm. Mean lethal concentration of cadmium acetate for cachamoto was 22.96 mg/l in 96 h, and the following external biomarkers were observed: lethargic swimming in the surface, exophthalmia, mucus hypersecretion, corneal opacity, changes in skin pigmentation, asphyxia, hemorrhage in eyes and operculum, unraveling of fins, and accumulation of liquid in the abdominal cavity. Cadmium acetate effects on fish hematological parameters showed a significant reduction in hematocrit and hemoglobin concentration in all of the tested concentrations.

Keywords : cadmium; toxicity; LC50-96h; hematological parameters; Caroní river.