The effect of catalpol supplementation during in vitro culture medium on bovine embryo development

In this thesis, oocytes obtained from ovaries of Holstein cattle were used. The obtained kumulus oocyte complexes were evaluated and transferred to maturation medium. Oocytes transferred to maturation medium were incubated at 38.5°C and 5.5% CO2 for 21-24 hours. After maturation, the oocytes were determined for the degree of cumulus expansion (Grade-I, Grade-II and Grade-III). The oocytes were then transferred to in vitro fertilization medium with semen prepared for fertilization and incubated for 22 hours at 38.5°C and 5.5% CO2. Before the in vitro culture stage, the possible zygotes were divided into four groups. The first group (Cat-5 group, n=180) received 5 µmol/L catalpol, the second group (Cat-25 group, n=193) received 25 µmol/L catalpol and the third group (Cat-50 group, n=173) received 50 µmol/L catalpol before in vitro culture. No supplementation was made to the culture medium of the fourth group (Control, n=183). Embryos obtained after culture were evaluated according to IETS criteria. After determining the developmental stages of the embryos after in vitro culture, only the embryos in the blastocyst stage were stained with differential staining method and cell numbers were determined. TUNEL method was used to determine cell death and apoptotic index. In addition, ROS and GSH levels in embryos were determined by fluorescent staining technique. The blastocyst rates of the groups were 34.83%, 29.63%, 22.29% and 27.17%, respectively. Consistent with these data a statistically significant difference (P<0.048) was observed between the groups. In addition, it was determined that ROS level and apoptotic index were low and GSH levels were high in the Cat-5 ve Cat-25 groups depending on the dose change. As a result, it was determined that catalpol addition to the culture medium in in vitro embryo production in cattle increased the rate of reaching blastocyst in the Cat-5 and Cat-25 groups, but the rate of reaching blastocyst in the Cat-50 group was lower than the control group and others. Therefore, it is thought that addition of different doses of catalpol to in vitro culture medium increases the rate of reaching blastocyst, decreases ROS level and apoptotic index and increases GSH level.