Effects of water-accommodated fraction of diesel fuel on seahorse (Hippocampus reidi) biomarkers.

The present work aimed to investigate the effects of acute (12, 24, 48 and 96 h) and subchronic (168 and 336 h) exposure of seahorse, Hippocampus reidi to water-accommodated fraction (WAF) of diesel fuel on biotransformation parameters, antioxidant defenses and DNA integrity. In addition, a recovery experiment was performed, where the organisms remained in absence of the contaminant for 336 h, after WAF exposure for 168 h (totaling 504 h). At the end of each experimental protocol, the concentration of pyrene-, benzo(a)pyrene- and naphthalene-type metabolites in bile, hepatic activity of glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT), as well as lipid peroxidation (LPO) levels in hepatocytes, were analyzed, in addition to the DNA damage and the micronucleus (MN) test in the peripheral blood. It was observed that both acute and subchronic WAF exposure affected the investigated parameters in different ways. In general, the exposed groups presented higher mean values for the investigated parameters if compared with their respective controls. After the recovery experiment, the mean values of PAH metabolites, LPO, DNA damage and MN frequency were significantly lower than those of animals exposed for 168 h, indicating that the recovery period was appropriately long for the evaluated biomarkers return to the control levels. The results indicated that the selected H. reidi biomarkers proved to be adequate and complementary tools in determining the first impacts of acute and subchronic exposure caused by WAF of diesel fuel in fish, as well as their recovery in clean water.