Reduced food consumption triggers abortion in antibiotic-treated pregnant rabbits: Insights from a pair-feeding study

In embryo-fetal developmental toxicity studies in rabbits, antibiotic administration is often accompanied by reduced food consumption and abortion. This study aimed to investigate whether reduced food consumption, independent of antibiotic exposure, was sufficient to induce abortion and explore potential mechanisms. Pregnant rabbits were assigned to three groups (n = 5/group): oral administration of the fluoroquinolone antibiotic DC-159a group, a pair-fed group receiving the same daily amount of diet as the DC-159a group, and a control group fed ad libitum. DC-159a administration from gestational days 6-18 caused a marked and sustained reduction in food consumption and abortion in all dams. Notably, all pair-fed dams also aborted. Changes in blood chemistry consistent with undernutrition were observed in both groups. Serum progesterone began to decline several days before abortion, and ovarian histopathology suggested luteal dysfunction. These findings indicate that reduced food consumption is the primary trigger of abortion in rabbits treated with DC-159a, indicating the involvement of compromised luteal function under nutritional stress.