Toxic effects of dietary polybrominated biphenyls on mink.

Serial levels of fireMaster FF-1, a commercial mixture of polybrominated biphenyls (PBB), and tissues from chickens and a cow that had previously consumed PBB were fed to mink to ascertain the chronic effects of the commercial and "metabolized" form of this compound on mink. Diets that contained 6.25 ppm (or more) PBB were lethal to adult mink within 10 months. One to 2.5 ppm dietary PBB fed for 9 months had an adverse effect on litter size, kit weight at birth, and kit survival. The data suggest that the PBB derived from contaminated beef and poultry was more toxic than the original PBB. The clinical signs of PBB poisoning in mink were food rejection, weight loss, and unthrifty appearance, and fatty infiltration of the liver. Based on these findings, mink must be considered highly susceptible to PBB toxicity. PBB residue levels 60 times the amount in the diet were found in the adipose tissue of the PBB-treated animals.