title: Behavioural and gill histopathological effects of acute exposure to sodium chloride in moneda (Metynnis orinocensis).
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.
authors.affiliation: Research Group on Reproduction and Toxicology of Aquatic Organisms (GRITOX), Instituto de Acuicultura, Universidad de los Llanos, Km 4 vía Puerto López, Villavicencio, Meta, Colombia.
authors.forename: Yohana M
authors.initials: YM
authors.lastname: Velasco-Santamaría
authors.forename: Pablo E
authors.initials: PE
authors.lastname: Cruz-Casallas