281 INFLUENCE OF DEFINED AND COMPLEX CULTURE MEDIA ON FERTILIZATION AND EMBRYONIC DEVELOPMENT OF IN VITRO-MATURED CAPRINE OOCYTES

Abstract

Complex media containing serum and/or co-culture with somatic cells result in satisfactory development, although the undefined conditions make it impossible to examine requirements of the embryos. Our objective was to compare defined and complex culture systems for their ability to support normal caprine embryonic development. In total, 3844 selected cumulus oocyte complexes (COC) were used for maturation in TCM-199 containing 10% newborn calf serum (NCS), 3 mg mL^-1 BSA, 5 μg mL^-1 FSH, 5 μg mL^-1 LH, and 1 μg mL^-1 estradiol-17β and 10 ng mL^-1 epidermal growth factor. After 27 h of maturation, oocytes were separated from cumulus and corona cells by treatment with 0.1% hyaluronidase and by passing through a fine-bore pipette. They were then washed in sperm TALP and fertilized in a drop of fertilization TALP (20% estrous goat serum and 10 μg mL^-1 heparin) containing 1 to 2 × 10⁶ spermatozoa per mL. Oocytes-sperm after 18 h of co-incubation were washed in embryo development medium 15 to 20 times and randomly divided into 3 groups. Fertilized oocytes were cultured for 10 days in TCM-199 containing 10% NCS and 4 mg mL^-1 BSA (group 1; n = 1511), synthetic oviductal fluid (SOF) containing 10% NCS and 4 mg mL^-1 BSA (group 2; n = 1333) or potassium simplex optimization medium (KSOM) containing 10% NCS and 4 mg mL^-1 BSA (group 3; n = 1000). The cleavage rate for groups 1, 2, and 3 were 13.6, 11.7, and 31.4%, respectively. All data were analyzed by one-way ANOVA; developmental data were arc sin transformed. The cleavage rate was significantly higher (P < 0.01) for group 3 than for groups 1 and 2. Similarly, embryo development up to morula stage was higher (P < 0.05) in KSOM compared with TCM-199 and SOF. This study shows that good development of embryos can be obtained in a completely defined medium and was better in KSOM than in SOF.