Effect of sperm capacitation and fertilization media on IVF and early embryo development of prepubertal goat oocytes

Abstract

Experiments were carried out to develop an improved IVF system for prepubertal goat oocytes matured in vitro. Cumulus oocyte complexes (COC) were obtained by slicing ovaries from slaughtered prepubertal goats. Oocytes were matured in TCM199 supplemented with 20% estrous goat serum (EGS) + 10 μ/mL FSH + 10 μg/mL LH + 1 μg/mL estradiol 17β for 27 h at 38.5°C in 5% CO 2 in air. In Experiments 1 and 2, freshly ejaculated spermatozoa were capacitated in 1 of 3 media: TALP/H, modified Defined Medium (mDM) and mH-M199 with 50 μg/mL heparin for 45 min. Matured oocytes were fertilized in TALP, mDM or mH-M199 in Experiment 1 and in TALP in Experiment 2. In Experiment 3, three media were used for sperm capacitacion and fertilization: Treatment A (control group): spermatozoa were capacitated in mDM with 50 μg/mL heparin for 45 min and fertilized in TALP medium with 1 μg/mL hypotaurine; Treatment B: spermatozoa were capacitated in mDM with 50 μg/mL heparin + 388 μg/mL caffeine for 30 min and fertilized in TALP medium without hypotaurine; Treatment C: spermatozoa were capacitated in mDM with 50 μg/mL heparin for 45 min and fertilized in TALP medium with PHE (20 μM penicillamine, 10 μM hypotaurine and 2μM epinephrine). At 24 h post insemination, the ova were transferred to a granulosa cell monolayer, and early embryo development was evaluated until Day 8. In experiment 2, the results show, that mDM plus heparin for sperm capacitation and TALP medium with hypotaurine for oocyte fertilization provided the highest proportion of penetrated oocytes, both total number (79.6%) and normal fertilization (55.1%), whereas the use of caffeine (44.6 and 31.2%, total and normal fertilization rate, respectively) and PHE (31.8 and 20.6%, total and normal fertilization rate, respectively) as motility enhancers did not improve the results obtained in the control group (48.7% and 37.2%, total and normal fertilization rate, respectively). These were no differences for the results of morulae and blastocysts.