IN VITRO FERILIZATION OF BOVINE OOCYTES RECOVERED FROM A SLAUGHTERHOUSE

Abstract

In vitro fertilization (IVF) was performed on 379 bovine ooc ytes harvested by follicles aspiration from 106 ovaries removed from prepuberal heifers in a slaughterhouse. Oocytes maturation wa s done in a CO 2 incubator in three different variants, using eithe r TCM culture media supplemented with 10% FCS, or 10% FCS and vitamin A, or 10% FCS and cystine. Groups of 15 oocytes into 50 �l micro-drops covered with mineral oil were cultured for 24h. Oocyte maturatio n was microscopically evaluated and had a rate of 5 9.5, 69.0, and 74.0% for the three culture media, respectively . For the actual IVF step, the motile sperm from 2 commercial straws of frozen semen was harvested on percoll gra dient centrifugation. Two groups of 15 matured oocytes were placed in Fert-TALP medium supplemented with either 6mg/ml BSA, or 6mg/ml BSA, 0.222 mg/ml Na pyruvate and 30 �g/ml heparin. Within each of the two droplets of fe rtilization medium containing 15 oocytes, 200,000 sperm were added and incubated at 38.5°C, 5% CO 2, for 20h prior examination and selection of cumulus-free and fertilized oocytes. Fertilization rates estimated after 2 - 3 days, were 53.3 and 73. 3% for the two fertilization media, respectively.