Pathology of experimentally induced polybrominated biphenyl toxicosis in pregnant heifers
Moorhead, P.D.; Willett, L.B.; Brumm, C.J.; Mercer, H.D.
Journal of the American Veterinary Medical Association 170(3): 307-313
1977
ISSN/ISBN: 0003-1488 PMID: 188792 Document Number: 120522
Toxicosis was induced in pregnant Holstein-Friesian heifers by giving polybrominated biphenyls in gelatin capsules at the rate of 25 g/day, (approximately 67 mg/kg body weight). Clinical signs were anorexia, excessive lacrimation and salivation, diarrhoea, emaciation, dehydration, depression, and abortion. Fever was not evident. Values for serum GOT, LD, blood urea nitrogen, and bilirubin were increased. Changes in packed cell volume haemoglobin content, total erythrocyte and leukocyte counts, and differential leukocyte counts were minimal and reflected dehydration and secondary infection. The principal urine changes were decreased specific gravity and moderate proteinuria. Gross necropsy findings included dehydration; subcutaneous emphysema and haemorrhage; atrophy of the thymus; fetal death with concomitant necrosis of coryledons; kidneys that were enlarged, pale tan to gray; thickened wall of the gallbladder; inspissated bile; oedema of abomasal folds; mucoid enteritis; linear haemorrhage and oedema of the rectal mucosa; and secondary pneumonia. Microscopic changes were most marked in the kidneys, gallbladder, and eyelid. In the kidney, the principal changes were extreme dilatation of collecting ducts and convoluted tubules, with epithelial degenerative changes of cloudy swelling, hydropic degeneration, and separation from the basement membrane. Common changes in the gallbladder were moderate to marked hyperplasia and cystic dilatation of the mucous glands in the lamina propria. The changes in the eyelids were characterized by hyperkeratosis, with accumulations of keratin in hair follicles of the epidermis and squamous metaplasia with keratin cysts in the tarsal glands. Clinical signs and lesions of toxicosis did not develop in heifers given the polybrominated biphenyls at the rate of 0.25 mg and 250 mg/day for 60 days. Initially these rates were approximately 0.00065 mg/kg and 0.65 mg/kg of body weight, respectively.