Evaluation of a TEST-yolk sperm capacitation system for use in bovine in vitro fertilization.
Bovine sperm acquire the ability to penetrate zona-free hamster oocytes (capacitation) after incubation in TEST-yolk buffer. Our objective was to determine whether such sperm could penetrate zona-intact bovine oocytes in vitro. Bovine cumulus enclosed oocytes from 2- to 5-mm follicles were incubated in maturation medium for 24 h at 37 degrees C. Ejaculated bovine semen was diluted 1: 10 in TEST-yolk buffer, cooled to 4 degrees C, and stored for 8 h to induce capacitation. Sperm were then washed thrice in pH 7.6, .15 M NaCl containing .1% bovine serum albumin V (37 degrees C) and diluted to 2 x 10(6) sperm/ml in fertilization medium. Droplets of fertilization medium containing capacitated sperm, killed sperm, or no sperm were made under paraffin oil. Oocytes (matured 24 h) were added and cocultured with sperm for 8 h and then transferred to fresh fertilization medium for 40 h. After 24 h, 53% of the oocytes had matured (metaphase II). The fertilization rate of the metaphase II oocytes (203) with TEST-yolk capacitated sperm was 87%, whereas the parthenogenetic controls were 2 and 0%, respectively. Therefore, TEST-yolk buffer can be used to capacitate bull sperm for in vitro fertilization.
Ijaz
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A
Department of Animal Science, University of Minnesota, St. Paul 55108.
Hunter
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AG
D000818:Animals; D002021:Buffers; D002417:Cattle / Q000502:physiology*; D002478:Cells, Cultured; D003470:Culture Media; D005260:Female; D005307:Fertilization in Vitro; D008297:Male; D008540:Meiosis; D008677:Metaphase; D009865:Oocytes / Q000254:growth & development / Q000502:physiology; D013075:Sperm Capacitation; D013084:Sperm-Ovum Interactions
D002021:Buffers; D003470:Culture Media