Effect of chloridazone on the animal organism

The acute toxic effect of the herbicide chloridazone and mitochondrial respiration were investigated and typical clinical signs of intoxication were described in rats (Wistar), pheasants (Phasianus colchicus) and sheep (Slovak Merino). The LD50 of chloridazone was calculated to be for rats 800 mg/kg bw (range 552 to 1160 mg/kg bw) and for pheasants 3684 mg/kg bw (range 1768 to 7677 mg/kg bw). According to WHO chloridazone is moderately toxic for rats and slightly toxic for pheasants. The LD50 for sheep is 161 mg/kg bw (range 76 to 340 mg/kg bw). Chloridazone thus presents an acute risk for ruminants, which is in coincidence with the WHO classification characterising it as a very toxic compound. The following clinical features of intoxication were observed after p.o. administration of chloridazone: apathy, dyspnoea, hyperventilation, hypersalivation (sheep - foam hypersalivation), paralysis, tonic-clonic convulsions and death in clonic convulsions. Very quick rigor mortis. Chloridazone interfered with mitochondrial respiration in the liver of rats yet its mode of action was different from that of succinate substrate or glutamate-malate. Succinate dependent respiration was significantly decreased in both states (3 and 4) of respiration. Glutamate-malate respiration was not changed in state 4, though it significantly increased in state 3 after ADP administration. RCP (respiration control proportion) value was increased on using either of the substances.