Alpha-Lipoic acid supplementation during in vitro culture of abattoir- and OPU-derived bovine oocytes improves embryonic quality

The Ovum Pick-Up (OPU) technique offers a rapid path to genetic improvement. Embryonic genome activation (EGA) is crucial for successful embryonic development and occurs in two phases: minor EGA (MNEGA) from 2-cell to 8-cell stages, and major EGA (MJEGA) from 8-cell to 16-cell stages. Supplementation with alpha-lipoic acid (ALA) during MNEGA using abattoir derived-oocytes has been shown to enhance in vitro embryo production. Two experiments were carried out in the study at hand. Experiment I aimed to evaluate ALA effects on embryo development and quality during MJEGA using abattoir-derived oocytes. Oocytes were treated with either a Control in vitro culture (IVC) medium or 2.5 µM ALA during MJEGA. The ALA presented a trend to increase the blastocyst cell number on day 7 (P = 0.06), along with reducing ROS levels and increasing GSH levels (P ≤ 0.05). Experiment II aimed to verify whether the results from abattoir- derived oocytes could be extrapolated to OPU-derived oocytes. The treatments included a Control, 2.5 µM ALA during MNEGA, and 2.5 µM ALA during MJEGA. The ALA supplementation during MJEGA improved the total blastocyst rate on day 8 (P = 0.04), with a trend towards increased blastocyst cell number on day 7 (P = 0.09). No improvements were observed in MNEGA. Overall, ALA supplementation during MJEGA is more effective than during MNEGA for improving the embryonic quality of OPU-derived oocytes.