Toxicity of herbicides 2,4-D and MCPA for rats and rabbits

Abstract

A subacute toxicity test using 2,4-dichlorophenoxyacetic acid (2,4-D, 10 mg·kg-1 and 100 mg·kg-1) and 4-chloro-2-methylphenoxyacetic acid (MCPA, 15 mg·kg-1 and 150 mg·kg-1) was carried out on Wistar rats (n=60) and New Zealand White rabbits (n=30) of both sexes. The lower doses of 2,4-D and MCPA used in our experiments were chosen based on the estimate that such doses would be present in feed of plant origin treated with the concentrations of both herbicides recommended by the manufacturer; the higher ones were sublethal doses. Herbicides 2,4-D and MCPA in our trial did affect neither body weight in adult rats and rabbits and their offspring nor weights of inner organs or the red and white blood cell count. The mucous membrane of the stomach and small intestines in rats treated with high doses of both herbicides was slightly inflamed and swollen. In rabbits, some of the semen characteristics changed during the trial; both herbicides acted in different directions. At the end of the trial the concentration of serum testosterone was significantly higher (p < 0.05) in rabbits treated with MCPA than in controls. The number of surviving young per litter at weaning in the MCPA group of rabbits was lower than in controls. No evident toxic effects on the viability and the ossification processes were observed in the young of treated rabbits.