BLASTOCYST FORMATION FOLLOWING INTRACYTOPLASMIC INJECTION OF IN-VITRODERIVED SPERMATIDS INTO BOVINE OOCYTES

Various types of male gametes, such as spermatozoa, spermatids and spe rmatids obtained after the in-vitro division of secondary spermatocyte s, were injected into the in-vitro matured bovine oocytes in order to examine the possibility of utilizing in-vitro derived spermatids for i ntracytoplasmic injection, There were no significant differences in th e development of bovine oocytes injected with various types of male ga metes (cleavage rate, 31.0-37.8%; morula rate, 11.1-18.2%; blastocyst rate, 4.4-11.4%), Similarly, 22.0% of sham-injected oocytes (injection of medium plus polyvinylpyrrolidone) cleaved parthenogenetically but none of them developed to morula stage, There were no significant diff erences in embryo quality (assessed by cell number) of blastocysts obt ained by the injections of various types of male gametes (124.0 +/- 9. 6-152.5 +/- 15.5), This study demonstrates that various types of sperm atogenic cells can be used for intracytoplasmic injection of oocytes t o produce viable embryos.