Changes in blood and urine composition from feeding polybrominated biphenyls to pregnant Holstein heifers.

The toxicity of a commercial preparation of polybrominated biphenyl was determined in 24 pregnant Holstein heifers that were alloted randomly to one of four experimental groups given 0 (I), .25 (II), 250 (III), and 25,000 (IV) mg per day of fireMaster BP-6 for 60 days or until the animals became moribund. Clinicopathologic determinations were on day -1 prior to dosing, days 15, 30 and 60 during dosing, and following dosing on days 80, 110, 150, and 190 from start of dosing. In addition, samples were collected from moribund heifers of Group IV immediately prior to necropsy. Toxicity was not evident in heifers in Groups I, II, or III. Toxicity was induced in heifers in Group IV. Glutamic-oxaloacetic transaminase of serum was increased and calcium decreased as early as day 15 whereas significant increases in lactate dehydrogenase, urea nitrogen, and bilirubin, and decreases in albumin were not observed until day 30 in heifers of Group IV. Analysis of urine from moribund heifers of Group IV revealed moderate proteinuria and decreased specific gravity. Evaluation of clinicopathologic data has suggested that the polybrominated biphenyls fed were renal toxins with no clear evidence of hepatotoxicity.

Effects of polybrominated biphenyls on health and performance of pregnant Holstein heifers.

The toxicity of a commercial blend of polybrominated biphenyls was determined in 24 pregnant Holstein heifers that were allotted randomly to one of four experimental groups given 0, .25, 250, or 25,000 mg/day of fire-Master BP-6. The polybrominated biphenyls were mixed with finely ground corn and given by bolus for 60 days or until the animal became moribund. Average body weight of heifers at onset of experiment was 381 kg. No clinical signs of toxicosis were evident in heifers fed 0, .25 or 250 mg/day. Toxicosis was induced in heifers fed 25,000 mg/day resulting in reduced dry matter intake, body weight, heart rate, and respiration rate. Clinical signs were anorexia, emaciation, dehydration, excessive lacrimation and salivation, diarrhea, depression, and abortion or fetal death. All heifers fed 25,000 mg/day became moribund within 33 to 66 days.

Pathology of experimentally induced polybrominated biphenyl toxicosis in pregnant heifers.

Toxicosis was induced in pregnant Holstein-Friesian heifers by giving polybrominated biphenyls a in gelatin capsules at the rate of 25 g/day. Initially, this dosage was approximately 67 mg/kg of body weight. Clinical signs were anorexia, excessive lacrimation and salivation, diarrhea, emaciation, dehydration, depression, and abortion. Fever was not evident during the experiment. Values for serum glutamic-oxalacetic transaminase, lactic dehydrogenase, blood urea nitrogen, and bilirubin were increased. Changes in packed cell volume, hemoglobin 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 hemorrhage; atrophy of the thymus; fetal death with concomitant necrosis of cotyledons; kidneys that were enlarged, pale tan to gray; thickened wall of the gallbladder; inspissated bile; edema of abomasal folds; mucoid enteritis; linear hemorrhage and edema 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.