Determination of Embryotoxic Dose Limit of Doxycycline and Its Effects on Some Long Bones by In Ovo Model

The aim of this study was to determine the embryotoxic and teratogenic effects of doxycycline on chicken embryos. Eggs placed in the incubator were checked with an ovoscope on the 7th day, and a total of 210 fertile chicken eggs were randomly divided into 7 groups. Doxycycline was applied to the experimental groups at 2500, 1250, 625, 312, and 156 μg/50 μL volumes, respectively. Group 6 was evaluated as the Negative Control Group. This group was placed in the incubator again without any treatment. Group 7 was administered 50 μL of 0.9% NaCl solution used as the solvent of the drug. The number of live and dead embryos was determined after the completion of incubation. Mortality was observed depending on the dose, and death was determined in all chicks at the highest dose (2500 μg/50 μL, p < 0.05). No macroscopic anomalies were observed. While a decrease in mortality rates was observed depending on the dose (p < 0.05), the mortality rate in the 156 μg/50 μL dose (Group 5) was similar to the Positive and Negative control groups (p > 0.05). Femur and tibia parameters could not be measured because all embryos in Group 1 (2500 μg/50 μL) died. The length and thickness of the right and left femur and tibia in Group 2 (1250 μg/50 μL) were statistically significantly (p < 0.05) lower than those of the other groups. As a result, it can be stated that doxycycline use should be avoided in pregnant mammals, especially during the development phase of organs, unless necessary.