Effect Of Different Factors On In Vitro Embryo Production Of Sheep

This study was conducted to investigate the effects of different factors on in vitro embryo production of sheep. The results are as follow:1. To examine the effects of melatonin supplementation during IVM culture, the COCs were cultured in IVM medium supplemented with 0,10-5,10-7 or10-9mol/L of melatonin for 24h, maturation rate was observed in each group. However, the maturation rate of COCs cultured with 10-7mol/L melatonin was higher than other groups, but the difference was not significant with other groups(P>0.05). The oocytes of each groups were cultured after parthenogenetic activation, the results shown:there were no significant differences in the rates of cleavage or blastocyst formation among the groups. The index (12.22～18.18%) of apoptosis in blastocysts derived from oocytes matured with melatonin were significantly lower (p<0.05) compared to those (21.30%) of oocytes matured without melatonin. Moreover the index of apoptosis in blastocysts derived from oocytes matured with 10’9mol/L melatonin was significantly lower (p< 0.05) than other groups.2. The fresh ram semen was stored at 25℃ and 4℃ after dilution, then used to IVF. The results shown:there were no significant differences in the cleavage rates and blastocyst formation rates among the groups(P>0.05).3. To examine the effects of different concentrations of sheep serum on the IVF. The fertilization medium supplements with 2% and 20% sheep serum. The results shown: there were no significant differences both in the rates of cleavage and blastocyst formation among the groups(P>0.05).4. Compared the effects of two different semen dilutions on the IVF. The semen stored at 25℃ after treatment with LTGC and SOF,then used to IVF. According to the results, there were no significant differences in the rates of cleavage and blastocyst formation between two groups(P>0.05).5. To examine the effects of melatonin supplementation during IVC medium supplemented with 0,10’5,10-7 or 10’9mol/L on the development and quality of parthenogenetic embryos, according to results:there were no significant differences in the cleavage rates among the groups(P>0.05). However, the blastocyst formation rate of embryos derived from cultured with 10-7,10’9mol/L melatonin were significantly higher (p<0.05) compared to others of oocytes cultured without melatonin. Besides, the index of apoptosis in blastocysts derived from oocytes cultured with melatonin was significantly lower than that from the control(p<0.05), and oocytes cultured with 10-5mol/L melatonin (17.56%) was significantly higher than that from the group 10-7mol/L and 10-9mol/L(P<0.05).