EXPERIMENTAL CHRONIC INTOXICATION OF CHICKENS WITH POLYCHLORINATED-BIPHENYLS (DELOR 103)

The effect of long-term intake of feed contaminated with polychlorinat ed biphenyls (PCB) in the form of Delor 103, a technical preparation ( 42% chlorine), on the dynamics of development of the morphological cha nges in the organs of chickens was investigated in an in-vivo experime nt. Brown Hisex layer hybrid cockerels from a commercial flock were fe d a feed mixture contaminated with Delor 3 in dosed of 25 mg. kg-1 or 50 mg . kg-1 from 1 day to 10 weeks of age. At 2-week intervals they w ere weighed and sacrificed and relative mass of the bursa of Fabricius and spleen was determined. The lymphoid organs, liver, kidney, caecal valve, Harder's gland, oesophagus, gonads, skin and other grossly cha nged organs were subjected to histological examination. In evaluating the bursa of Fabricius, thymus and spleen use was also made of semiqua ntitative criteria. Pooled samples of the pectoral muscle were analyse d for PCB content. The alterations in the clinical status, body growth and relative mass of the bursa of Fabricius and spleen correlated wit h the dose level. Even the lower dose produced lymphocytotoxic, hepato toxic and vascularotoxic effects. The changes observed at the end of t he experiment corresponded to chronic intoxication with PCB. Of intere st were the findings of adenoma of the pancreas and mainly dystrophic lesions in the central and peripheral nervous system.