Toxicity assessment of Dibutyl phthalate in Grass carp: an integrated biomarker approach

Phthalates are the common plasticisers used around the globe. Dibutyl phthalate (DBP) is a ubiquitous, extensively used in cosmatics and frequently present in the aquatic environment. Therefore, toxic effects of DBP were evaluated in term of oxidative stress and biochemical biomarkers. For this reason, a 21 day exposure was conducted by exposing grass carp with graded concentrations of DBP (1, 10, 100 and 1000 µg/L). After 21days, stress biomarkers:, lipid peroxidation (LPO), catalase (CAT) activity, glutathione-S-transferases (GST) activity and level of reduced glutathione was evaluated in liver, kidney and gills. Alkaline phosphatase (ALP), aspartate transaminase (AST), urea and creatinine were evaluated in liver and kidney homogenates respectively. Moreover, effect of DBP on all biomarkers were evaluated through integrated biomarker response (IBR). Exposure of fish to DBP resulted in oxidative stress in grass carp as evidenced by an increase in lipid peroxidation and decrease in antioxidant enzymes. DBP exposure also resulted in increased liver’s ALT and AST levels. Urea and creatinine were also significantly increased in kidney after exposure to DBP. The IBR showed bad scores as the DBP concentration increased, with the highest one (1000 µg/L) presenting a score >250x the value for the control treatment. Additionally, the IBR/n showed that the most impacted organ was the kidney, followed by the liver and the gills. The obtained results show the need for deeper research into the effects of DBP on fish and their impact on different organs.