Plasma antioxidant and hepatic enzymes activity, thyroid hormones alterations and health status of liver tissue in common carp (Cyprinus carpio) exposed to lufenuron

Abstract

The aim of this study was to determine the effect of lufenuron as new practical pesticide on the health of one important fish species in aquaculture, common carp. The LC50 of lufenuron after 96 h was 1.089 mg/L in juvenile common carp (48 ± 4.25 g in weight). Behavior and mortality were investigated during the acute toxicity. The fish showed loss of equilibrium, erratic and lateral swimming and motionless. To determine the chronic effects of lufenuron, the fish distributed into 8 tanks as two treatments (4 tanks per treatment). They were exposed to 0 (control) and lufenuron (0.1 mg/L; 10% LC50-96 h concentration) and sampled at 7th and 21st days for blood biochemical analyses and at 21st day foe liver histopathological examinations. Plasma total protein and globulin levels of the lufenuron-exposed fish decreased significantly compared to the control fish. Lufenuron exposure increased plasma ALP, ALT and AST activities compared to the control group. Sampling time and lufenuron exposure had interaction effect on the plasma LDH activity. The plasma LDH activity of the lufenuron-exposed fish increased after 7 days exposure compared to the control group, but showed no significant difference compared to the control group after 21 days. The plasma T3 level declined in the lufenuron-exposed fish without significant changes in the plasma T4 levels. The plasma SOD activity in the lufenuron-exposed fish increased compared to the control group at the first sampling time, but there was no significant difference in the plasma SOD activities of the lufenuron-exposed and control fish after 21 days. Lufenuron exposure and sampling time had no independent or interaction effects of the plasma CAT activities. Plasma TBARS levels of the lufenuron-exposed fish had no significant difference compared to the control group after 7 day, but significantly increased after 21 days lufenuron exposure. Hepatocyte necrosis, melanomacrophage aggregates and sinusoidal space expansion were observed in the liver samples of the lufenuron-exposed fish.