Effect of a polychlorinated biphenyl mixture on swine reproduction and tissue residues.

A commercial polychlorinated biphenyl (PCB) mixture containing 42% chlorine by weight was fed at the dose level of 20 ppm to 3rd-litter sows throughout gestation and nursing. Treated sows differed significantly (0.05% level) from control sows in the number of live pigs they farrowed. Treated sows also had more mummified fetuses. Performance of live-born pigs was not affected by feeding PCB to the sows during nursing. Pathologic changes in the sows included hypertrophy of liver and erosion of stomach. Two treated sows, 1 of which did not conceive, had signs of extensive chronic septicemia. Slight atrophy of spleen and thyroid gland was observed in pigs from treated sows. Blood and tissue residues of PCB were less than 0.5 ppm in both sows and pigs, but the relative amounts of PCB components varied among sows and pigs, as well as among tissues. Fat concentrations of total PCB in sows ranged from 4 to 20 ppm and those of component residues varied from 0 to 60 ppm.