Histopathological Changes in Kidney of Fish Clarias garipinus Exposed to Cypermethrin (25% EC)

Pesticide contamination poses a significant threat to aquatic ecosystems, with cypermethrin, a widely used synthetic pyrethroid, raising concerns due to its toxic effects on non-target organisms. This study investigates the histopathological alterations in the kidneys of Clarias gariepinus following exposure to sub-lethal concentrations of cypermethrin (25% EC). Healthy fish were acclimatized and subjected to a static renewal bioassay to determine the 96-hour LC50 value, recorded at 0.273 ± 0.007 µL/L. Specimens were then exposed to 1/5th of the LC50 concentration for 14 days, after which renal tissues were examined microscopically. Histopathological analysis revealed significant renal damage, including glomerular shrinkage, widening of Bowman’s space, tubular degeneration, nuclear pyknosis, karyolysis, and cytoplasmic vacuolation. Additionally, hydropic swelling and interstitial tissue disintegration indicated severe nephrotoxic stress. These findings suggest that cypermethrin exposure compromises kidney function in C. gariepinus, potentially impairing osmoregulation and excretion. The observed renal damage underscores the ecological risks associated with cypermethrin contamination in freshwater bodies, highlighting the urgent need for stricter pesticide regulation and environmental monitoring. This study provides crucial insights into pesticide-induced nephrotoxicity in fish, reinforcing the importance of sustainable agricultural practices to mitigate aquatic pollution.