In-vitro penetration of pig oocytes matured in culture by frozen-thawed ejaculated spermatozoa

W. H. Wang, K. Niwa, K. Okuda

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125 Citations (Scopus)


Pig oocytes matured in culture were inseminated with frozen-thawed ejaculated spermatozoa without preincubation in modified tissue culture medium (TCM) 199. High penetration rates (85-89%) and increased incidence of polyspermy were obtained at 25-100 x 106 spermatozoa/ml. Wide variation in penetration rates (16-89%) was observed in oocytes inseminated in medium containing 5mM caffeine and at 25-50 x 106 spermatozoa/ml obtained from 6 boars, regardless of sperm motility. At 25-50 x 106 spermatozoa/ml, penetration rates of oocytes were dependent upon the concentration of caffeine in the medium: there was no penetration without caffeine, but penetration was highest (89%) with 5mM caffeine. None of the oocytes was penetrated in the medium supplemented with heparin at 5-40 μg/ml. When heparin was included in the medium with 5mM caffeine, it inhibited the efficacy of caffeine to promote sperm penetration of oocytes.

Original languageEnglish
Pages (from-to)491-496
Number of pages6
JournalJournal of Reproduction and Fertility
Issue number2
Publication statusPublished - 1991


  • Frozen ejaculated sperm
  • In-vitro fertilization
  • Oocyte
  • Pig

ASJC Scopus subject areas

  • Physiology
  • Embryology
  • Molecular Biology
  • Obstetrics and Gynaecology
  • Developmental Biology


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