| There were three parts in this investigation.In Part 1,we collected and analyzed the data of ovary weight,ovary morphology,corpus luteum morphology and follicle size. The objective was to investigate ovary quality which derived from local abattoirs.In Part 2,the objective was to investigate the effect of bulls,culture density, co-culture with or without granulose cell on the efficiency of IVP bovine embryos,in order to optimize bovine embryos IVC system.In Part 3,we focused on the effect of culture medium on the developmental competence of IVP Early Bovine Embryos.For selecting the best culture medium, blastocyst rates,cell number and cryosurvival were assesed.The results were as follows:1 In this investigation,we collected 95 pairs(190) bovine ovaries in May, September and December.Assessed for the ovary morphology by the standard from Varisanga,there were 32.63%good ovaries(CL-NO),46.31%fair ovaries(NO-NO, CL+DF-NO),and 5.26%poor ovaries(DF-NO).Apart from this,there were 10.53% useless ovaries which had cysts;For follicle size,85%of follicles were small follicles (2～4mm),the large follicles(6～8mm) were less than 6%.2 Small follicles in 5～10g group were significantly higher than≤5g group(P＜0.01),and it was significantly higher than≥10g group(P＜0.05).Middle follicles in 5～10g group were significantly higher than≥10g group too(P＜0.05).There were no significant differene in the large follicles among three groups.Positive correlation was found between ovaries weight and small follicles’ number,but when weight over 10g, there was no correlation.3 Ovary morphology had effect on follicle number of different size.Group of CL-NO and NO-NO had more small and totall follicles than group of DF-NO and CY-NO(P＜0.05).There was no difference in middle follicles among each groups(P＞0.05),but there was lower large follicles in group of CY-NO than other groups(P＜0.05).4 Following IVM,oocytes were inseminated with sperm from four Simmental bulls, which number was 6303,6305,6306 and 6307 respectively.Cleavage rates were assessed at 48 h post insemination(hpi) and the proportion of oocytes developing to the blastocyst stage was recorded on Day 7,Day 8 post insemination(pi).The results were that cleavage rates in 6303 were significantly higher than others(P＜0.05);There were no significant difference in the blastocyst rates between 6303 and 6305(P＞0.05),but both were significantly higher than 6306 and 6307(P＜0.05).The results displayed that the selection of bulls producing sperm with a high fertilizing capacity is an important factor in achieving successful and consistent IVP results.5 After IVM,IVF,presumptive zygotes were randomly allocated to three culture density(25μL/embryo,5μL/embryo and 1μL/embryo),groups of 20～25 presumptive zygotes were placed in every culture droplets.Cleavage rates were assessed at 48 h hpi and the proportion of oocytes developing to the blastocyst stage was recorded on Day 7, Day 8 pi.There were no significant difference in differenct treatments on the cleavage rates,blastocyst rates and hatched blastocyst rates(P＞0.05).6 After IVM,IVF,presumptive zygotes were randomly co-cultured with or without GCM(Granulosa Cell Monolayer).Cleavage rates were assessed at 48 h hpi and the proportion of oocytes developing to the blastocyst stage was recorded on Day 7,Day 8 pi. The results indicated that there were no significant differences in cleavage rates, blastocyst rates and hatched blastocyst rates(P＞0.05).It was indicated that co-culture with GCM was not benefit to early embryos development in this experiment.7 After IVM,IVF,presumptive zygotes were randomly placed to three kinds of culture medium(KSOM,CR1 and SOF).The day of fertilized was 0 day,the blastocysts were collected on Day 7,Day 8.Several of blastocysts were stained with Hoechst 33342, the rest were freeze-thawing by OPS(Open Pulled Straw).After thawing,to record embryo survival rates in 12h,24h and 36h respectively.There was a significantly higher cleavage rates and total blastocyst rates in KSOM than CR1(P＜0.05);On Day 7, blastocyst rates of KSOM was higher than CR1 and SOF(P＜0.05),but embryo survival rates were no significant difference among three treatments(P＞0.05).The result indicated that KSOM is the optimal medium in IVP bovine embryos. |
PDF Full Text Request