Toxic effects upon exposure to benzo[a]pyrene in juvenile white shrimp Litopenaeus vannamei

The purpose of this study was to investigate the toxic effects induced by benzo[a]pyrene (BaP). In the present study, juvenile white shrimp Litopenaeus vannamei were exposed to BaP for 21 days at four different concentrations as 0, 0.03, 0.3 and 3μg/L. Detoxification system parameters, transcription of metabolism-related genes, and damage indexes were investigated for screening. It showed mRNA expression levels of superoxide dismutase (SOD), cytochrome P450 (CYP) 1A1 and glutathione-S-transferase (GST) in hepatopancreas were significantly induced at day 3 by 0.3 and 3μg/L BaP, and returned to the initial level afterwards. 7-Ethoxyresorufin O-deethylase (EROD), GST and SOD activities in gill and hepatopancreas were also induced by 0.3 and 3μg/L BaP, while T-AOC and GSH contents were reduced after BaP exposure. The study also showed that 0.3 and 3μg/L BaP caused damage effects, while 0.03μg/L BaP treatment did not exhibit any damage effects. Moreover, according to the correlation analysis results, we conclude that EROD activity, GST activity and GSH content in hepatopancreas can be used as defense biomarkers; DNA strand breaks, lipid peroxidation (LPO) level and protein carbonyl (PC) content in gill and hepatopancreas can be used as damage biomarkers; EROD activity, GST activity, GSH contents and damage effects of DNA strand breaks, LPO level and PC content in hepatopancreas can be used as combined biomarkers. These results will provide information not only on potential biomarkers that could be effectively applied to biomonitor aquatic environment to contamination, but also provide information on toxic effects of this specie.