Metabolic enzyme activities, metabolism-related genes expression and bioaccumulation in juvenile white shrimp Litopenaeus vannamei exposed to benzo[a]pyrene.

The purpose of this study was to investigate the impact of benzo[a]pyrene (BaP) on metabolic detoxification system and bioaccumulation of white shrimp Litopenaeus vannamei. In this study, juvenile white shrimp L. vannamei were exposed for 21 days at four different concentrations of 0, 0.03, 0.3 and 3μg/L. Detoxification enzyme activities of phase I (aryl hydrocarbon hydroxylase (AHH), 7-ethoxyresorufin O-deethylase (EROD), epoxide hydrolase (EH)) and phase II (glutathione-S-transferase (GST), sulfotransferase (SULT), uridine diphosphate glucuronyl transferase (UGT)) were determined, and results showed that all the detoxification enzyme activities increased in a dose-dependent manner except for the low BaP exposure. Transcription of genes was detected and measured by real-time RT-PCR. It showed that at day six BaP increased cytochrome P450 (CYP) 1A1, GST, SULT visa aryl hydrocarbon receptor (AhR) mRNA expression in a dose-dependent manner, which suggests that they could be potential targets of BaP that disrupt the detoxification system. The consistency of their responses to BaP exposure implies that AhR action may be involved in invertebrate CYP regulation. Additionally, BaP bioaccumulation increased rapidly first and showed an incoming plateau. Besides, the enzyme activities and bioaccumulation in the hepatopancreas were higher than those in the gills. These results will not only provide information on BaP metabolic mechanism for this species, but also scientific data for pollution monitoring.