Antioxidative Potential of Red Deer Embryos Depends on Reproductive Stage of Hind as a Oocyte Donor

SIMPLE SUMMARY: Deer breeding tends to select animals for obtain the high meat quality and in case of males preferred shape and weight of antlers. Fertilization in vitro (IVF) using high-indexing parents results favorable features. Moreover, evaluation of effective method of IVF on Cervus elaphus as a model, will be useful for application on Cervids in danger of extinction. The effectivity of IVF depends on quality of gametes and proper development of embryo. The aim was to compare the blastocyst stages of red deer embryos in respect of IVF efficiency, morphology, apoptotic and proliferative abilities, and antioxidative potential according to the reproductive status of hinds. We used three experimental groups, including the ovaries collected post mortem on the 4th and 13th days of the estrous cycle (farmed animals) and during pregnancy (wild animals). Frozen-thawed epididymal semen was used for IVF. Blastocyst quality, apoptotic, and antioxidative potential of blastocysts were evaluated. Results indicate that red deer embryos on blastocyst stage received in vitro collected from hinds on 4th day of the estrous cycle as an oocyte donor are characterized by better antioxidative potential and qualities to those developed from oocytes collected from hinds on 13th day of the estrous cycle and pregnancy. ABSTRACT: The aim was to compare the blastocyst stages of red deer embryos in respect of in vitro fertilization (IVF) efficiency, morphology, apoptotic and proliferative abilities, and antioxidative potential according to the reproductive status of hinds. We used three experimental groups, including the ovaries collected post mortem on the 4th and 13th days of the estrous cycle and during pregnancy (n = 18). After oocyte maturation, frozen-thawed epididymal semen was used for IVF. Blastocyst quality, apoptotic potential by determining the mRNA expression of BAX, BCL-2, OCT4, SOX2, and placenta-specific 8 gene (PLAC8), and antioxidative potential of blastocysts were evaluated by determining the mRNA expression of CuSOD, MnSOD, and GPX as well as the enzymatic activity of superoxide dismutase and reduced glutathione. The highest development rate of expanded blastocyst, mRNA expression of BCL-2, OCT4, SOX2, and PLAC8 and mRNA expression and enzymatic activity of the antioxidative factors increased (p < 0.05) in blastocysts developed from the oocytes collected on the 4th day, compared to those developed from the oocytes collected on the 13th day of the cycle and during pregnancy. Our study indicates that the 4th day of the estrous cycle is the most effective period for oocyte collection for IVF and embryo development in hinds, considering quality parameters and antioxidative potential of the blastocysts.