Toxicity of certain polychlorinated and polybrominated biphenyls on reproductive efficiency of caged chickens.

The biphenyls tested with caged White Leghorn pullets were polychlorinated biphenyl (PCBs) Aroclors 1232, 1242, 1248, 1254 and 1016 and polybrominated biphenyl (PBB) PBP-6 at the 5, 10 and 20 p.p.m. levels. These pollutants exerted no adverse effects on egg production, egg weight, egg shell thickness, feed consumption, adult body weight changes, livability and fertility after 8 weeks of biphenyl feeding, irrespective of biphenyl level or compound. Hatchability of fertile eggs as a result of biphenyl feeding was significantly affected by 10 or 20 p.p.m. and by three PCB compounds (Aroclors 1232, 1242, 1248). The hatchability (%) of eggs laid by pullets fed 10 and 20 p.p.m. declined to 78 and 45, respectively, for Aroclor 1232, 48 and 5 for Aroclor 1242 and 40 and 5 for Aroclor 1248 after 6 weeks of biphenyl feeding, as compared with 90 for the control group. The most common embryonic abnormality was edema in the neck and rump areas. Biphenyl supplementation in the maternal diet also caused a shift in the peak pattern of embryonic death. Progeny growth as a result of biphenyl in the maternal diet was significantly depressed by 10 or 20 p.p.m. and by Aroclors 1242 and 1248. The level of the three PCBs found to be toxic to chickens appears to lie somewhere between 5 and 10 p.p.m.