title: Sex ratio of early embryos fertilized in vitro with spermatozoa separated by percoll.
abstract: Early bovine embryos were obtained by in vitro fertilization and sexing carried out by chromosome analysis. Separation of bovine X- and Y-bearing spermatozoa was performed using Percoll density gradient centrifugation and the enrichment of X-sperm proportion was investigated. Through treatment with vinblastin sulfate and podophyllotoxin, 880 (48.6%) of 1812 embryos at two- to seven-cell stages at 48 to 53 h after sperm-egg incubation produced metaphase spreads, and 399 (45.3%) of these were successfully sexed; the sexable rate reaching 53.4% for four-cell embryos. Sexing rates for embryos from the original sperm of two bulls were 69.6% (32 46 ) in Bull A and 54.2% (58 107 ) in Bull B. Embryos fertilized in vitro with sperm sedimented at the bottom of sperm centrifuged under conditions (I) 50 to 85% of Percoll, 15 degrees C; (II) 30 to 80%, 10 degrees C; (III) 30 to 80% 20 degrees C; (IV) 30 to 90%, 20 degrees C, gave rise to male sex ratios of (I) 58.3% in Bull A and 53.5% in Bull B, (II) 65.9% in Bull A, (III) 49.3% in Bull B and (IV) 66.7% in Bull B. In conclusion, Percoll density gradient centrifugation under these four conditions was unsuccessful in separating X- and Y-bearing bull spermatozoa.
authors.affiliation: NODAI Research Institute, Tokyo University of Agriculture, Sakuragaoka, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Shioya
authors.forename: H
authors.initials: H
authors.lastname: Masuda
authors.forename: A
authors.initials: A
authors.lastname: Hanada
authors.forename: T
authors.initials: T
authors.lastname: Nakahara