Long-Range Exposure of Broiler Chicks to Pcb - Clinical and Biochemical-Changes

Veterinarni Medicina 39, 1994, 397-405

In view of preventive human and veterinary medicine negative effects of PCB are serious mainly with respect to their stability in food chain. A low degree of biotransformation in living organisms and PCB transfer through food chain have resulted in the ban on PCB production and in restriction of their use. Important restriction measures concerning the use of PCB-based products were already taken in the eighties. In spite of the ban on PCB production in this country (1984), their inventories along with contaminated refuse make around 10 000 tons. The data indicate the existence of sources of food chain contamination. Information campaign as well as targeted PCB monitoring are important components of prevention of environmental contamination. The originally monitored PCB sum has currently been replaced by a system of monitoring oriented to particular PCB congeners. The objective of this paper is to present clinico-biochemical changes observed in broiler chicks after a long-range exposure to a relatively low rate of original commercial types of PCB. Sixty one-day cockerels Hybro (paternal line) were included in a trial. The chicks were housed in boxes with deep litter under continuous lighting. They had free choice of feed and water. Control and experimental groups contained 30 broiler chicks each. A PCB blend (Delor 103 and Delor 105 - original commercial products of PCB from Chemko Strazske) were added at a concentration of 50 mg/kg feed to the diet of experimental group. Numerous clinical and biochemical parameters were investigated in the conditions of long-range applications (1 - 42 days). Clinically visible negative effects could be seen in broiler chicks after two weeks of PCB application. There were no significant differences in broiler weight. Feathering, mucosa paleness and disturbed uniformity of chicks were observed. Evaluation of clinico-biochemical changes and pathological lesions (liver enlargement, edematous swelling of kidneys, hydropericardium, hemorrhages, etc.) revealed an increased variability of chick sensitivity to PCB exposure. A significant drop of the relative weight of thyme (P < 0.01) and bursa Fabricii weight (P < 0.05) was found. The decrease in the organ weight is related to conspicuous atrophy of lymphatic tissue. The liver weight of exposed chicks was increasing significantly (P < 0.01). Hepatotoxic effects of PCB also induced large metabolic disorders. The level of alkaline phosphatase in blood serum had the significantly higher values against the control group of chicks (P < 0.05). Similarly, a highly significant increase (P < 0.01) in cholesterol and triglycerides in blood serum of the chicks with dietary PCB was recorded. The results describing the changes in the levels of lipophilic vitamins in chick liver are also related to the suggested clinico-biochemical picture. Vitamin A levels significantly decreased (P < 0.01) in the group of PCB-exposed chicks. The overall negative clinico-biochemical profile of chicks is also documented by changes in the blood picture. A highly significant drop of erythrocyte counts, hemoglobin and hematocrit values (P < 0.001) was found in the group of PCB exposed group. Long-range applications of PCB to broiler chicks result in large metabolic disorders, cardiovascular lesions and marked hepatotoxic or nephrotoxic effects

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