Toxicological effects of sub-lethal doses (1/10th of LD50 and initial residues) of pyriproxyfen, fenitrothion and spinosad were studied in male albino rats. The ratio of certain organ to body weight, some blood components and enzyme activities(plasma cholinesterase and alkaline phosphatase) were determined. One tenth of the LD50 of the three insecticides showed a significant decrease in the weight of kidneys, and spleen of the tested animals with respect to the total weight, while there was no significant change in the weight of the liver with respect to the total weight. Regarding the initial deposits of the three insecticides, the results showed that there was no significant difference on the ratio of liver to total body weight for spinosad and fenitrothion, while the initial deposit of pyriproxyfen showed a significant decrease in the weights of liver, spleen and kidney with respect to the total body weight.
One tenth of the LD50 had insignificant effect for the insecticides fenitrothion and spinosad mostly on the number of red and white blood cell counts, while the dose of pyriproxyfen significantly reduced the number of white cells from 13 x 103 cell/ml in the control treatment to 4.3X103 cell/ml. The three insecticide treatments showed a significant increase in hemoglobin in comparison to the control. There was no significant effect for both doses of 1/10th the LD50 and the initial deposit on Hematocrite concentration and the average volume of the red blood cells, except for the doses1/10th of the LD50 of spinosad and initial deposit of fenitrothion in which there was a significant increase in the average volume of the red cells in comparison to the control.
The two doses of insecticides showed a little inhibition of cholinesterase activity which ranged from 9.61 to 38.46% for both doses of the three insecticides. A significant increase in the activity of the enzyme alkaline phosphatase was recorded. Creatinine level was increased when animals were treated with both doses of pyriproxyfen. Fenitrothion treatment showed a decrease in creatinine level. The treatment of 1/10th of LD50 of spinosad did not affect the level of creatinine, while the initial residue of spinosad showed a significant increase with respect to the control.