EFFECT OF DDT ON REPRODUCTION IN RAT

The feeding of technical DDT [80% 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane; 17% 1,1,1-trichloro-2-(o-chlorophenyl)-2 2-(p-chlorophenyl)ethane;2%1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] at levels of 0, 20, and 200 ppm to Sprague-Dawley-derived rats was begun with a weanling parent generation and terminated with weaning of third litters from the F1 generation. Three groups of like lineage composition contained 12 females and 6 males each. Females were bred at 16 and 24 weeks. All litters were examined after parturition and at 21 days for number, weight, sex, and health, and daily for survival. Breeding stock was selected from second litters. The same experimental plan was followed for F1 generation animals except that females were bred for a third time at 52 weeks. All animals were autopsied when they finished their role in the experiment. DDT ingestion produced no apparent effect on fecundity of dams or viability of young. Comparison of total numbers of pregnancies in each group indicated that there was no effect of DDT on fertility of 16- or 24-week-old rats, but data obtained for an individual family line in the experiment suggested the possibility of an adverse effect of DDT in matings of marginal fertility. The reproductive performance of 52-week-old rats indicated that DDT may also exert a protective effect against age decrement of the reproductive process. The 200 ppm DDT diet produced a significant increase in the occurrence of ringtail, a disease of obscure etiology that affects suckling rats. © 1969.