The Influence of Oviductal and Uterine Fluid Supplementation on the In Vitro Development and Quality of Cloned Sheep Embryos

Somatic cell nuclear transfer (SCNT) has great potential for the replication of high-commercial-value animals, threatened wild species for conservation purposes, and transgenic animals for biomedical purposes. However, SCNT has a low success rate due to intrinsic factors of the technique itself, which leads to low rates of embryonic development and epigenetic alterations in cloned embryos. The objective of this study was to evaluate the effect of OF-UF on the intracellular concentrations of ROS and GSH and the development of cloned and parthenogenetic <i>Ovis aries</i> embryos. The results do not show a beneficial effect on the development of parthenogenetic and cloned embryos at concentrations of 0.5% OF-UF. Furthermore, at 1% OF-UF, an adverse effect was observed in cloned embryos at the blastocyst stage and 2% OF and UF in parthenogenetic embryos during the first divisions. Decreases in ROS and GSH levels were observed in the parthenogenetic blastocysts treated with 1% OF-UF, but not in the clones, in which a higher concentration of GSH and a similar concentration of ROS were observed. No effect of OF-UF was observed on embryonic development and redox balance in sheep embryos cloned via handmade cloning.