Author(s): COSTA, P. H. DA; NOGUEIRA, A. R. de A.; AZEVEDO, E. B.; GONZALEZ, M. H.

Summary: Selenium is one of the most important trace element micronutrients for the globalbiota, mainly due to its role in protecting against oxidative stress. However, this element canbecome toxic when present at concentrations slightly higher than those needed for metabolicpurposes. It can be transferred through the food chain toward higher trophic levels, withbioaccumulation and biomagnification leading to possible toxicity. This study investigates thebioconcentration and toxicity potential of Se(IV) in Nile tilapia (Oreochromis niloticus). After 7days of exposure, Se concentrations in the fish tissues were in the order: liver ? stomach > gills >muscle. In bioconcentration tests, the uptake constant (ka) ranged from 0.34 to 4.68 mL g?1 d?1,while the clearance rate constant (kd) ranged from 0.12 to 0.36 d?1. The tissues presented highbioconcentration factors (BCF) ranging from 2.67 to 12.73, demonstrating the ability of Se(IV) toconcentrate in muscle, gills, and stomach. Although the data for the liver could not be fitted by themodel used, the measured Se(IV) concentrations were approximately six times higher than thosefound for the stomach, indicating that the ka, kd, and BCF values were very high. Estimated LC50values lower than 10 mg L?1 suggested that Se(IV) could be considered very toxic to the fish.

Publication year: 2024

Types of publication: Journal article

Unit: Embrapa Southeastern Livestock

Keywords: Anatomy, Elements, Impurities, Liquid chromatography, Selenium, Toxicity