Subchronic toxicity and neurobehavioural effects of alphacypermethrin in rats

Alphacypermethrin is a highly active pyrethroid insecticide effective against a wide range of pests in agriculture, public health and animal husbandry. In this study, doses of 4, 8, 16 and 32 mg/kg alphacypermethrin were prepared in corn oil (10%) and orally administered to four experimental groups (n = 10; 5 male and 5 female in each group) by gavage once daily for 90 days. Mortality and clinical findings together with behavioural changes in rats were observed daily, weekly and monthly during the study period. Death occurred in all experimental groups. No statistical difference was found in mean lifetimes between the control and 4 mg/kg group for both genders (p>0.05). However, mean lifetimes of 8, 16 and 32 mg/kg groups were statistically different from the control and 4 mg/kg groups (p<0.05) for both gender. Also, mean lifetimes of 8 mg/kg group were statistically different from the 16 and 32 mg/kg groups for both gender (p<0.05). Similar as other Type II pyrethroids, typical symptoms were seen in dead animals approximately 3 hours after the last dose. Alphacypermethrin caused reduction of body weights and feed consumption. In addition, it caused catatonia in two male rats in the 4 mg/kg group. No significant changes were determined in other observed behaviours. These findings indicate that the vehicle (corn oil) has a great influence on the toxicity of alphacypermethrin. Also, this research may be beneficial for the risk analysis of alphacypermethrin as well as a base for further research in this area.