Pathological changes of experimental polychlorinated biphenyl poisoning in chickens

Two experiments were carried out to study pathological changes of polychlorinated biphenyl (PCB) "KC 400" poisoning. In them chickens were administered with this agent for a relatively short time. Eleven experimental diets were prepared to contain 11 different PCB concentrations, 4,800 ppm being the highest, respectively. They were given to broiler chickens in initial feeding and later. All the chickens fed 300 ppm and higher concentrations of PCB died, showing the serious dilatation of uriniferous tubules and involution of the bursa of Fabricius, by the time when they reached 12 days of age. All the chickens, except a very few, fed 100 ppm remained alive at the end of the experimental period, when they were 41 days of age and exhibited such edematous changes as hydropericardium. Few chickens fed 50 ppm and less manifested pathological changes until the end of the experimental period, when they were 22 days of age. Two experimental diets were prepared to contain 600 and 200 ppm of PCB, respectively. They were given to layer chickens in initial feeding and later. These layers were sacrificed for autopsy every fourth day. A gain in body weight was retarded mostly in those fed 600 ppm. Dilatation of uriniferous tubules and involution of the bursa of Fabricius began in the very early stage of experimental feeding in both groups. Hydropericardium occurred to many of the chickens fed 200 ppm in the late stage of the experimental period. The results of both experiments indicated that there was no essential difference in changes of PCB poisoning between broiler and layer chickens. The principal changes of the poisoning were dilatation of uriniferous tubules, involution of the bursa of Fabricius, and edematous alterations. They appeared in a relatively early stage of the experimental period of PCB feeding. Their severity was strongly dependent upon the concentration of PCB contained in the diet.