Supplemental vitamins A, D, and E improve OPU-IVP efficiency in postpartum dairy cows by alleviating oxidative stress.

Optimizing ovarian superstimulation to improve oocyte quantity and quality is crucial for ovum pick-up and in vitro embryo production (OPU-IVP) in cows. In this study, we aimed to evaluate whether a single intramuscular injection of combined vitamin A, D, and E (VADE) during ovarian superstimulation enhances outcomes and milk yield in early lactation Holstein donor cows. Postpartum cows (40-60 days in milk) were randomly assigned to control (n = 79, superstimulation only) or VADE (n = 82, superstimulation + VADE injection at protocol initiation) groups. OPU-IVP outcomes, milk yield, and oxidative stress markers in serum, follicular fluid (FF), granulosa cells (GC), and oocytes were assessed. VADE supplementation significantly increased follicle number at OPU (34.3 vs. 27.0). It enhanced the number (8.9 vs. 6.2) and proportion (56.8% vs. 48.0%) of high-quality cumulus-oocyte complexes, leading to more blastocysts per donor (3.9 vs. 2.3). However, we did not observe that VADE helped restore milk yield during and after the ovarian superstimulation-OPU procedure. Transcriptomic analysis of GC revealed that VADE treatment downregulated genes involved in oxidative stress response. VADE treatment significantly reduced malondialdehyde levels in the serum and FF on OPU day, increased serum glutathione peroxidase activity, and decreased reactive oxygen species levels in the FF and oocytes. In addition, VADE treatment significantly downregulated ESRRA mRNA expression in GC. In conclusion, VADE supplementation during ovarian superstimulation improves oocyte quality and OPU-IVP efficiency in early lactation cows by alleviating oxidative stress, which is a readily implementable strategy for enhancing genetic utilization in high-yielding dairy herds.