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, 1
5 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 t
reated with the concentrations of both herbicides recommended by the manufa
cturer; the higher ones were sublethal doses.
Herbicides 2,4-D and MCPA in our trial did affect neither body weight in ad
ult 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 sma
ll intestines in rats treated with high doses of both herbicides was slight
ly inflamed and swollen. In rabbits, some of the semen characteristics chan
ged 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 numbe
r 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.