Abstract:

Through investigating morphological changes and organ primordia formation of the porcine embryos，we want to lay the foundation for organgenesis study in pig，and for utilization of pigs as the model of human disease.Porcine embryos from day 7.0 to 18.5 postinsemination were collected to observe appearance of embryos by stereomicroscopy.Organ primordial of 14.0-18.5 d embryos were inquired using paraffin section and HE staining.The results showed that blastocysts had hatched from zona pellicuda at 7.0-7.5 d.The majority of conceptuses were filamentous，and the primitive streak emerged at 12.0-12.5 d.And embryos were in somite stage at 14.0-14.5 d.The data of tracking organ primordial were shown as follows.For renal formation，the pronephros appeared at 15.0-15.5 d，and the mesonephros emerged at 16.0-16.5 d and remained at 18.0-18.5 d.For brain development，the prosencephalon and the mesencephalon were clearly visible at 15.0-15.5 d.Four brain vesicles and telencephalon were observed at 18.0-18.5 d.For eyes formation，optic vesicle appeared at 15.0-15.5 d，and optic cup was showed at 18.0-18.5 d.For stomach and liver，the buds emerged at 16.0-16.5 d，and liver bud transformed into hepatic cord at 18.0-18.5 d.For heart generation，atrium and ventricle as well as valves were formed at 18.0-18.5 d.The results showed that bronchial tree was observed at 18.0-18.5 d.These results indicate that heart，liver，kidney，brain，lung，stomach，limb buds，etc.are beginning to form during 15.0-18.5 d.