[Toxicologic evaluation of supermethrin, a pyrethroid insecticide, in rabbits and pheasants].

Basic information about a toxicologic hazard of the pyrethroid supermethrin (Research Institute of Chemical Technology, Bratislava) is presented in this paper for the conditions of acute intoxication in rabbits and pheasants and in the conditions of subacute intoxication in pheasants. The insecticide supermethrin under observation contains a cyanide groups in its molecule and can be included in the group of type II pyrethroids comprising among other substances also cypermethrin. Supermethrin is an analog of the latter and it has a different proportion of cis- and trans-isomers. At acute intoxication, supermethrin was applied to adult rabbits at doses of 2,000; 3,000; 4,000; 5,000 and 6,000 mg/kg and to adult pheasants at doses of 2,000; 4,000; 5,000 and 6,000 mg/kg live weight. Supermethrin dissolved in sunflower oil at a 1:2 ratio was administered in the above differentiated doses at single application by a peroral tube. Not even the highest supermethrin dose (6,000 mg/kg live weight) caused any clinical signs of intoxication in the birds. This fact suggests that its LD50 for rabbits and pheasants will apparently exceed the value of 6,000 mg/kg l.w. At subacute intoxication, supermethrin was applied as dissolved in sunflower oil (at a 1:2 ratio) by per os tube at a dose of 500 mg/kg l.w. once a day within five days. The subacute doses of supermethrin did not induce, besides mild diarrhea at the end of the trial, any other clinical signs of intoxication in the pheasants. The negative effect of supermethrin (even though negligible) on the digestive tract of pheasants is in agreement with the results determined in sheep in the conditions of subchronic intoxication (Neuschl et al., 1995), Supermethrin administration in sheep resulted in permanent and intensive diarrheas. These findings clearly indicate that supermethrin administered at lower doses primarily affects the function of digestive tract. Tab. 1 shows the effect of supermethrin on the live weight of pheasants in the conditions of subacute intoxication. The negligible decrease in live weight recorded at the end of the trial was not due to supermethrin effects. It was also recorded in the control group. There were no significant differences between the control and experimental group. It was probably induced by the stress resulting from daily applications of the tested substance. In case the guidelines for its areal application (140 g/ha) are observed, it will not be toxic for rabbits and pheasants nor probably for hares and/or other gallinaceous birds. Supermethrin seems to be a little toxic substance according to WHO (1975) classification.