[The effect of polychlorinated biphenyls (PCB) on chickens: the effect of long-term administration of medium doses of Delor 103 on the levels of thyroxine, triiodothyronine and total calcium in the blood serum].

A trial with the continual administration of feed contaminated with the Delor 103 preparation (polychlorinated biphenyls--PCB) at a rate of 75 mg per kg for chicks lasted four weeks. The concentrations of serum thyroxine and triiodothyronine were found to decrease, the concentrations of total calcium increased and at the Delor 103 doses of 150 mg per kg even the phosphorus concentration and the activity of alkaline phosphatase in the serum of chicks decreased. The addition of potassium iodide to feed (250 mg per kg) did not influence the clinical picture of Delor 103 intoxication. The results confirm a finding that in the course of PCB intoxication severe disorders of the thyroid gland take place and calcium metabolism is disturbed. This finding is important in view of evaluation of the intoxication of young, growing chicks.