Influence of polychlorinated biphenyls in the laying hen.

Abstract Single Comb White Leghorn hens were fed diets containing 0, 5, 10, 20, 40 or 80 p.p.m. PCB as Aroclor 1242 for six weeks followed by six weeks of feeding a PCB-free diet. Dietary PCB did not influence egg production, egg weight, shell thickness or shell weight under the conditions of the experiment. Dietary PCB at the 80 p.p.m. level prevented eggs laid in the second week from hatching and hatchability was significantly reduced in the eggs from hens fed 40 or 20 p.p.m. PCB. A relatively small, but significant, reduction in the hatchability of eggs from the hens fed 10 p.p.m. PCB was obtained for the sixth week. Recovery from the effects on hatchability of feeding 20, 40, or 80 p.p.m. PCB was not complete after six weeks. The amount of yolk PCB required to influence hatchability was related to the rate of accumulation which was influenced by the dietary level. The hatchability of eggs from hens fed 80, 40 and 20 p.p.m. PCB were 0% (week 2), 8% (week 3) and 50% (week 6), respectively, with yolk concentration of 5.6, 5.4 and 6.2 p.p.m. PCB, respectively.