Developmental toxicity of Spinosad administered by gavage to CD rats and New Zealand white rabbits.

The insecticide Spinosad was administered by gavage to pregnant CD(R) rats at 0, 10, 50 or 200 mg/kg/day on gestation days (gd) 6-15 and to New Zealand White rabbits at 0, 2.5, 10 or 50 mg/kg/day on gd-7-19. Rats and rabbits were monitored for clinical signs of toxicity and body weight gains. At gd-21 (rats) or gd-28 (rabbits), maternal organ weights, reproductive parameters, fetal body weights, and fetal external, visceral and skeletal structures were evaluated. Rats given 200 mg/kg/day exhibited a 4% lower body weight on gd-12 and decreased body weight gains on gd-6-16 relative to controls. There was no maternal toxicity at 10 or 50 mg/kg/day, and no developmental toxicity in rats at any dose level. Rabbits given 50 mg/kg/day exhibited decreased feed consumption, reduced fecal output, body weight loss during the initial dosing period (gd-7-10) and a non-statistically significant decrease (31%) in body weight gain during the dosing period (gd-7-20). Two litters aborted due to maternal inanition. There were no maternal effects at lower doses, and no signs of developmental toxicity at any dose. Thus, the maternal no-observed-effect levels (NOEL) were 50 and 10 mg/kg/day in rats and rabbits, respectively, and the embryonal/fetal NOELs were 200 mg/kg/day in rats and 50 mg/kg/day in rabbits.