| The objective of this paper was conducted to establish an optimum in vitro culture system for bovine embryos, based on the techniques of in vitro maturation, in vitro fertilization and parthenogenetic activation of oocyte. Under the same culture condition, the development differences between fertilized embryo and pathenogenetic embryo were investigated. The results showed as follows:1. The addition of 10% or 20% bFF (bovine follicle fluid) in maturation medium obtained higher blastocyst rate (32.3% or 30.9%) than that in 5% or control treatment (21.8% or 22.7%, PO.05). In addition, the addition of 20% bFF in maturation medium inhibited the hatching of blastocyst.2. The examination was made of the effects of water quality in medium preparation on oocyte maturation in vitro and early development of parthenogenetic embryos. Two types of water were used in the experiment: three-distilled water and Mill-Q water. It indicated that the cleavage rate had no significant difference between medium prepared with two types of water. However, the frequency of development to the blastocyst stage in medium prepared with Mill-Q water (29.7%) was significant higher than with three-distilled water (10.1%, PO.05).3. The effect of different maturation time on the development of oocyte activated was investigated. It suggested that oocytes matured 28 h or 30 h before pathenogenetic activation resulted in higher blastocyte rate (30.5% or 29.4%) than those matured 24 h or 26 h (20.5% or 22.1%, PO.05).4. Oocytes were activated in mSOFaa medium with 5 u M ionomycin for 5 min, and then incubated with 2 mM 6-DMAP for 2 h, 4 h, 6 h or 8 h, the developmental capacity of them were compared. It implied that for 2 h incubation in 6-DMAPresulted in lower cleavage rate (67.4%) than for 4 h, 6 h, or 8 h treatments (80.6%, 84.1% or 79.8%). In addition, oocytes incubated for 4 h or 6 h in mSOFaa medium with 6-DMAP had significant higher blastocyst rate (33.3% or 30.4%) than those incubated for 2 h or 8 h (13.8% or 20.5%, PO.05).5. The effect of fertilization media, which included BO medium and BO+M199 mixtures in proportion (3:2, BM) on in vitro fertilization and the subsequent embryonic development of bovine oocytes was investigated. It showed that two types of fertilization media had the similar effect on the cleavage rate of fertilized embryos. But, the embryos at 2-cell stage fertilized in BM medium had significant higher capacity to develop to the blastocyst stage (31.4%) than those fertilized in BO (20.3%, PO.05).6. The experiment was conducted to determine the effect of oocyte-sperm interaction time on in vitro fertilization and the subsequent embryo development. The conclusion was that oocyte-sperm interaction for 6 h treatment resulted in lower cleavage rate (69.5%) than those for 9 h, 12 h or 24 h treatments (80.6%, 84.1% or 79.8%, PO.05). In addition, oocyte-sperm interaction in 6 h, 9 h or 12 h interaction had significant higher blastocyst rate (22.3%, 24.8% or 23.9%) than that for 24 h interaction (10.8%, PO.05).7. Presumptive oocytes were randomly divided into three groups, and then cultured in media with 0.6 mg/ml BSA, 0.3 mg/ml BSA+5%FBS or 0.3 mg/ml BSA+5%OCS, respectively. The results suggested that the frequency of development to the blastocyst stage was significant higher in media with 0.3 mg/ml BSA+5%FBS (20.4%) or 0.3 mg/ml BSA+5%OCS (29.9%) than in medium with 0.6 mg/ml BSA alone (P O.05). The effect of OCS on the development of embryos seemed better than that of FBS.8. In this experiment, presumptive oocytes were randomly cultured in different culture media including Ml99, mSOFaa or mBECMaa. It seemed that presumptive oocytes in mSOFaa or mBECMaa resulted in higher blastocyst rate (29.2%or 30.7%) than in M199 (18.0%, PO.05).9. Under the same culture condition, the development of fertilized embryos was compared with that of pathenogenetic embryos. It indicated that there were no difference on the development speed and the blastocyst rate between fertilized embryos and pathenogenetic embryos.
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