The effect of polyclorinated biphenyls in chickens: the effect of short-term administration of high doses of Delor 103 on the levels of thyroxine, triiodothyronine, sodium, potassium and calcium in the blood

The trial with a short-time receiving (7 days) of high doses of the preparation Delor 103 (PCB) to chickens (1000 mg.kg-1 feed stuffs) had a long-run negative effect on their state of health. Clinical picture of intoxication resembled an involution syndrome. A defect persistence of the conversion of thyroid hormone T4 to T3 was found. Regeneration of T4 hormone production was rather fast. Supplement of hormones T4 and T3 to feed had no significant influence on the course of intoxication, but it caused changes in concentrations of K+, Ca++, and the total calcium in the blood serum of the birds. Simultaneous supplement of Delor 103 moderated the intensity of changes induced by exogenous flow of thyroid hormones. Histological changes were demonstrated in the primary lymph organs, which supported of findings of immunosuppressive effect in PCB. Supplement of the thyreostatic Carbimazol (Carbimazolum/1-carbaetoxy-3-methyl-2-thioimidazolin um) caused no symptoms testifying to hypofunction of thyroid gland in chickens.