Effects of Ractopamine on the in vitro Development of 2-Cell Mouse Embryos

The study was to investigate the effects of ractopamine (RAC) on the in vitro development of 2-cell mouse embryos. The 2-cell mouse embryos were acquired from Kunming mice. Approximately four hundred embryos were randomly divided into 5 groups: control group (0 μM RAC), low-dose group (0.5 μM RAC), mid-dose group (5 μM RAC), high-dose group (50 μM RAC), and clenbuterol (CLB) group (50 μM CLB, positive control). Embryo development and morphologic variation were observed by microscopy. The results show that compared with the control group, the 2-cell embryos in the low-dose group were no difference at the blastocyst stage (P>0.05). A significant decrease in the developmental rates of the 2-cell embryos was observed in blastocyst stage in the mid-dose group (52.7%) and high-dose group (47.1%, P<0.01). Moreover, embryos cultured with RAC showed more granules, fragments, and degeneration than those in the control group. The results demonstrated that RAC has toxic effects on the development of embryos, and those effects are dose-dependent.