Biological Studies of Swine Exposed to 60-Hz Electric Fields. Volume 4: Growth, Reproduction, and Development. Final Report

摘要

Swine were exposed to uniform, vertical, 60-Hz, 30-kV/m electric fields for 20 hours/day, 7 days/week. The parental generation (F sub 0 gilts) was bred after 4 months on study; some were killed for teratologic study at 100 days of gestation (dg), and the others produced a first-generation (F sub 1 ) of offspring. The pooled incidence of terata in these litters was similar in the exposed and sham-exposed groups. The F sub 0 females, which produced the F sub 1 generation, were rebred after 18 months of exposure and were killed at 100 dg: malformation incidence in exposed litters (75%) was significantly greater than in sham-exposed litters (29%). Types of malformations were not dissimilar between the two groups. The F sub 1 gilts were bred at 18 months of age; there were indications of impaired copulatory behavior and decreased fertility in the exposed animals. Defective offspring were found in significantly more of the exposed litters (71%) than in sham-exposed litters (33%). The F sub 1 sows were bred again 10 months later, and teratologic evaluations were performed on their second litters at 100 dg. The percentage of litters with malformed fetuses was essentially identical in the exposed and sham-exposed groups (70 and 73%, respectively). The change in malformation incidences between generations and between the first and second breedings makes it difficult to unequivocally conclude that chronic exposure to a strong electric field caused developmental effects in swine, although it appears there may be an association. It is also possible that other factors, such as housing, inbreeding, disease or its treatment may have contributed to the results. 22 refs., 9 figs., 28 tabs. (ERA citation 11:012020)