Objectives: To assess fertilizability of in vitro matured bovine oocytes in different concentrations of bovine serum albumin (BSA) with or without caffeine or heparin.
Design: Interventional study.
Samples: In vitro matured bovine oocytes.
Procedure: Ovaries were removed from cows and heifers in local slaughterhouses, carried to the laboratory. Follicles were aspirated and intact oocytes were isolated and transferred into TCM -199 supplemented with 10% heat inactivated fetal bovine serum, cultured
for up to 24h in a CO2 incubator. After culture half of the oocytes were denuded and put into BO medium containing different concentrations of BSA and with or without caffeine or heparin and inseminated with frozen thawed semen. After 22-24 h inseminated oocytes were fixed for 3 days in acetic alcohol, stained in aceto orcein and examined under a phase-contrast microscope for the evidence of sperm penetration.
Statistical analysis: ANOVA and when a significance different was seen, Duncan's Multiple Range Test.
Results: When cumulus intact oocytes were inseminated in caffeine supplemented BO, there was no significant different among different concentrations of BSA (72%, 78%, 83% and 62% penetration rates for 0, 5mg, 10mg and 20mg/ml BSA respectively). However, in
cumulus-free oocytes, there was significantly lower penetration in protein-free medium comparing other concentrations of BSA (P<0.05). When inseminations of oocytes were carried in heparin¬supplemented medium, penetration of cumulus-intact and-free oocytes were lower in protein-free medium than those other concentrations of BSA.
Conclusion: When cumulus-free bovine oocytes are inseminated in vitro, heparin may have synergistic effects with protein. However, when cumulus-intact bovine oocytes are inseminated in vitro protein may be eliminated from medium, but caffeine and heparin are prerequisites for in vitro fertilization in this condition. J. Fac. Vet. Med. Univ. Tehran. 58, 3: 241-247, 2003.
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