Abstract
A microsurgical method which is available for sexing of pig embryo was developed. A total of 22 pig expanding blastocysts was subject to being bisected into two hemispheres by a glass needle: one was "inner cell mass (ICM)-half" which contained the whole ICM and approximately half of the trophoblast, and the other was "the trophoblast (Tr)-half" which had the remaining half of the trophoblast. After the microsurgery, the pairs of ICM and Tr halves were cultured for 20 hr, and the ICM halves were transplanted to recipient gilts and Tr halves were used for chromosome analysis. The rate of development of the transplanted ICM halves were 63.2% (12/19). This is approximately equal to the usual results obtained in transplantation of pig embryos. Sixteen (80%) of 20 chromosome specimens from the Tr halves showed one or more metaphase plates. The average of cells per specimens was 65.8. This result indicated that the micromanipulation method presented here is a suitable one for determining the sex of blastocysts of pigs. Enough cells for specimen preparation can be collected without descreasing embryo survivability.
