EFFECT OF INSECTICIDE-TREATED MAIZE ON HEART AND LIVER HISTOLOGY OF LAYING CHICKENS

Synthetic insecticides which are applied to treat crops leave residues that may negatively impact on environment, livestock and humans. Maize, the main ingredient in poultry feed has tendency to retain residue arising from treatment with insecticides. Therefore, the toxic effects of diets containing insecticide-treated maize were assessed on histology of hearts and livers of laying chickens. Five isonitrogenous and isocaloric diets were formulated to contain maize treated with 4 pre-planting insecticides at recommended doses: control (T1), 20% chlorpyrifos at 2 ml/Kg (T2), 20% imidacloprid and 20% metalaxyl-M at 2 g/Kg (T3), 20% thiamethoxam and 20% metalaxyl-M at 2.5/Kg (T4), 33% permethrin and 15% carbendazim at 2.5 g/Kg (T5). Sixty 25-week old laying chickens were randomly allotted to the diets for 14 days in a completely randomised design. No visible lesions were observed in the photomicrographs of hearts of chickens fed with diets containing insecticide-treated maize. Histology of liver of birds fed with T2 indicated severe widespread of vacuolar change of the hepatocytes. Those fed T3 showed dense periportal mononuclear cellular aggregates, as well as moderate congestion of blood vessels and sinosoids. Those T4 revealed mild to moderate dissociation of hepatic cords with the presence of a few periportal foci of mild mononuclear cellular aggregates, while those fed with T5 showed a few periportal foci of dense mononuclear cellular aggregates. Insecticide-treated maize indicated liver damage of the experimental chickens.