Author(s): VelascoSantamara YM, CruzCasallas PE
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Abstract To evaluate the toxicity of sodium chloride (NaCl), juveniles and adult Metynnis orinocensis were exposed for 96h to 0, 5, 10, 15, 20 or 40gL(-1) of salt. Food intake, behaviour, opercular frequency (OF), mortality, body weight and gill microscopic alterations were evaluated. Behavioural changes were observed in fish exposed to concentrations higher than 10gL(-1). Juveniles and adults showed a progressive decrease in the OF and body weight. Food intake decreased in concentrations below 15gL(-1). Juveniles and adults exposed to 15, 20 or 40gL(-1) had 100\% mortality. Lamellar congestion, hyperplasia and fusion were the common microscopic alterations at higher concentrations. The gill congestion severity increased with salt concentration. The LC(50) for juveniles and adults were 10.5gL(-1) and 10.8gL(-1), respectively. These results suggest that salt concentrations lower than 5gL(-1) are safe for preventive and therapeutic practices in Metynnis orinocensis; whereas prolonged exposure higher than 10gL(-1) is deleterious in this species. Copyright © 2007 Elsevier B.V. All rights reserved.
This article was published in Environ Toxicol Pharmacol
and referenced in Applied Microbiology: Open Access