Histopathological Alterations in Nile Tilapia Oreochromis Niloticus (L.) as Influenced by Dietary Antiparasitic Drug Emamectin Benzoate at the Recommended and Higher Doses for an Extended Period

Effect of dietary emamectin benzoate diets on fish

Abstract

The effects of the dietary antiparasitic drug emamectin benzoate (EB) on the biosafety and kidney, liver and intestine tissue histopathology of Oreochromis niloticus were assessed. Extended EB medication at the recommended dose (50 μg/kg biomass/day) for 21 days reduced survival, feed intake and biomass. A dose-dependent hepatotoxic, nephrotoxic and intestinal toxic effects of EB were noticed. Tubular degeneration, glomerulopathy, inflammation and necrotized renal interstitium in the kidney and glycogen-type vacuolation and cytoplasmic degeneration in the liver were observed. The intestine exhibited loss of absorptive vacuoles, mucinous degeneration, necrotized intestinal villi and absorptive region and inflammation. Lamina propria swelling was noticed in the higher-dosed groups. With the termination of medication, the pathological changes were reduced significantly, indicating the ability of fish to mount adaptive responses to recoup. The extended EB administration for 21 days is unlikely to produce adverse and irrevocable effects on fish at the recommended dose.