Effect of Polychlorinated Biphenyls (PCB) on the Infection of Chickens with Turkey Herpesvirus THV-BIO-I

Halouzka, R. and V. Jurajda: Effect of Polychlorinated Biphenyls (PCB) on the Infection of Chickens with Turkey Herpesvirus THV-BIO-I. Acta vet. Brno, 61, 1992: 133-139. The effects of polychlorinated biphenyls (Delor 103) on Brown Hisex chickens infected with vaccination turkey herpesvirus THV-BIO-I were studied in a 5-week experiment. One group of l-day-old chicks were infected in doses of approximately 10· PFU per bird and fed a commercial feed mixture K. Another group of chicks were infected in the same way and fed feed mixture K contaminated with PCB (Delor 103) at 50 mg. kg_1 feed mixture. Non-infected chickens fed non-conta­ minated feed mixture K were used as controls. At weekly intervals the chickens were subiected to serological examination and weighed, and their lymphoid organs, skin, nerves and gonads were examined histopathologically. PCB (Delor 103) produced a reduction in body mass and a disturbance in feather growth. The incidence of lymphoid cellulisates in the organs was not affec­ ted. The lymphoid organs of chickens merely infected with THV-BIO-I exhibited only moderate cytolytic changes; atrophy of the spleen and of the bursa of Fabricius were found at the end of the experiment. The lymphoid organs of chickens both infected and fed PCB (Delor 103) showed more conspicuous regressive changes from the 3rd week p. i. These may be a cause of vaccination failure. Post-infection antibody was not found in any of the birds. Brown Hisex chickens were apparently more resistant to the effects of PCB (Delor 103) than Brown Leghorn chickens used in a previous experiment. Brown Hisex chicken, PCB, Turkey herpesvirus THV-BIO-I, lymphoid organs, immunosuppression