Using the Amniotic Cavity of the Developing Chick Embryo for the In Vivo Culture of Early-Stage Mammalian Embryos ,

Abstract

The fertile chicken egg may provide an effective, inexpensive method for promoting the development of early-stage embryos from other species. Presently, the loss of viability associated with the in vitro culture of mammalian embryos is hindering the use of in vitro fertilization with farm animals. Consequently, alternative in vitro laboratory methods are needed for the culture of mammalian embryos. A new method has been developed that involves the culture of mammalian embryos in the amniotic cavity of a developing chick embryo. Chick embryos were placed into shell-less incubation (37 C) at the 72-h developmental stage. After 24 h of shell-less incubation, agarose-embedded mammalian embryos were injected into the amniotic cavity of the chick embryo. The mammalian embryos were first placed into a drop of liquid agarose. One to four embryos were then aspirated into a beveled injection pipette and cooled, allowing the agarose to harden. Following penetration of the amnion with the beveled pipette, the agarose cylinder containing the embryos was expelled into the amniotic cavity. The shell-less culture system was then returned to incubation at 37 C for an additional 72 to 96 h. Following incubation, the amniotic cavity containing both chick and mammalian embryos was isolated and the agarose-embedded mammalian embryos were harvested. Significantly more embryos developed in the chick embryo amnion than in the control medium alone. Results obtained using this method on laboratory animals (mice) and on domestic mammals (goats and cattle) indicate that the chick-embryo amnion can support the development of early-stage, mammalian embryos to the blastocyst stage of development. This unique approach may be an alternative to existing systems for culturing the embryo in vivo and in vitro.