Improving in vitro maturation and cleavage rates of buffalo oocytes
Anim Reprod, vol.6, n2, p.416-421, 2009
The aim of the present study was to improve in vitro maturation and cleavage rates of buffalo oocytes. Good quality oocytes were divided into two experiments. In Experiment 1 oocytes were cultured for 24 h in a CO2 incubator at 38.5o C either in TCM-199, Ham’s F-10, MEM or FertiCult medium supplemented with either 10% FCS or 0.3% BSA. Experiment 2 was carried out to investigate the effect of different hormones (either 50 µg/ml eCG, 50 µg/ml FSH or 1 mg/ml E2) added to four of the afore mentioned media enriched with 10% FCS at the same culture conditions. Matured oocytes were fertilized in vitro using frozen thawed semen capacitated with heparin and caffeine. The sperm-oocytes were co-cultured for 22 h in BO or TALP medium. The fertilized oocytes were cultured in either BO or TALP medium for an additional five days at the same culture conditions and checked daily for cleavage. Addition of FCS to all media led to a higher maturation rate, without any significant variation, than BSA did (75.6 vs. 71.3%). Although no influence on the maturation rate was observed, addition of eCG to TCM-199, Ham’s F-10 or MEM media resulted in a non-significant increase of in vitro maturation rate of buffalo oocytes compared to other hormonal additives to the same media. Furthermore, supplementation of maturation media with eCG resulted in a non-significant higher in vitro maturation rate of buffalo oocytes compared to FSH and E2 (80.4% for eCG supplemented media vs. 74.0% and 73.0% for FSH and E2, respectively). There was a non-significant difference in the cleavage rate of buffalo oocytes matured in TCM-199 supplemented with either sera or hormones and fertilized either in BO or TALP medium. However, the highest non-significant cleavage rate was achieved when oocytes were matured in TCM-199 supplemented with eCG and fertilized in TALP medium (50%). The overall cleavage rate was not significantly greater in TALP than in BO medium (33.7 vs. 15.5%). It could be concluded that supplementation of maturation media with FCS and/or eCG could successfully improve IVM rate of buffalo oocytes. Furthermore, high cleavage rate could be achieved when oocytes were matured in TCM-199 supplemented with FCS and eCG and fertilized in TALP medium.
buffalo, cleavage, IVF, IVM, oocytes