Hematologic, biochemical, genetic, and histological biomarkers for the evaluation of the toxic effects of fipronil for Rhamdia quelen

Abstract

This study aimed to determine the lethal concentration 50% (LC50) and behavioral, hematological, biochemical,histopathological, and genetic disorders of fipronil for Rhamdia quelen in acute toxicity tests for 96 h. To determine the LC50, 42 juvenileswere distributed in groups of 0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.8 mg L–1 of fipronil. For other evaluations 36 silver catfish were divided intocontrol, 0.3 mg L–1, and 0.4 mg L–1 groups. Blood, kidneys, livers, and gills were collected for evaluation. The LC50 calculated with probittyperegression was 0.811 mg L–1 at 48 h of study. There was total mortality of 0.8 mg L–1, reduction in hematocrit values, and increase inliver enzymes. Liver samples showed cytoplasmic vacuolization and cellular degeneration, among other changes. Gills presented vascularcongestion, complete fusion of secondary lamellae, and epithelial cell hypertrophy. In the kidneys, changes such as Bowman’s capsuleclearance, tubular degeneration, and glomerular capillary dilatation, among others, were common. Erythrocytes showed morphologicalalterations without increased micronucleus development. Fipronil induces a clinical condition of anemia, alterations in liver enzymelevels, nuclear erythrocyte changes, and liver, gill and kidney damage in the silver catfish.