The effects of spirodiclofen on histopathological, serum biochemical parameters and antioxidant enzyme activities in common carp (Cyprinus carpio, linnaeus 1758)

Spirodiclofen (SPF) is an acaricide that has been found to be effective in the management of two-spotted red spider (Tetranychus urticae) infestations in a variety of crops, including citrus fruits, soft and hard stone fruits, and nuts. The process of transporting SPF from agricultural areas to aquatic environments via drainage channels and evaporation has the potential to exert a toxic effect on fish. Carp (Cyprinus carpio) is selected as a suitable model organism for assessing the effects of environmental toxicants. The fish were exposed to SPF (0, 0.05, 0.1 and 0.3 mg/L) for a 21 days. Histopathological examinations revealed cellular degeneration and inflammation in the hepatopancreas, intestine, gonads and gill tissues. The examination of antioxidant enzyme activities and oxidative stress markers revealed that catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD) activities, as well as soluble protein levels, increased up to 0.1 mg/L SPF, and decreased as the concentration increased (p<0.05). The levels of malondialdehyde (MDA) increased significantly with increasing SPF concentration. Serum biochemical parameters revealed a decline in total protein (TP), albumin (ALB), and total cholesterol (CHOL) values concurrent with increased concentrations. Conversely, there were significant increases in creatinine (CRE) and uric acid (UA) levels (p<0.05). Principal Component Analysis (PCA) was performed on serum biochemical parameters to evaluate interrelationships and responses to SPF exposure. In conclusion, the findings indicate that SPF may cause toxicity in fish through oxidative stress, biochemical impairments, and tissue damage, and this poses a potential risk factor for aquatic ecosystems.