Comparative assessment of the biological effectiveness of a domestic medium for bovine oocyte aspiration

Аннотация

Background and Aim. In vitro embryo production is an important reproductive biotechnology for accelerating genetic improvement in cattle. The efficiency of this technology largely depends on the quality and developmental competence of cumulus–oocyte complexes (COCs) recovered during ovum pick-up (OPU). Aspiration media play an important role in maintaining oocyte viability during collection and subsequent handling. This study aimed to evaluate the biological efficacy of a newly developed domestic aspiration medium for bovine oocyte recovery and to compare its performance with that of
a commercial aspiration medium.
Materials and Methods. The study was conducted using six physiologically healthy Galloway donor cows aged 1–4 years. Oocyte aspiration was performed twice in each donor at a 14-day interval. The recovered COCs were assigned to experimental and control groups according to the aspiration medium used. A commercial aspiration medium was used in the control group, whereas a newly developed domestic medium based on modified Dulbecco’s medium was used in the experimental group. COC quality was evaluated immediately after aspiration by morphological assessment and after 24 h of in vitro maturation using fluorescence and polarization microscopy. Nuclear maturation, cumulus morphology, reactive oxygen species (ROS) levels, mitochondrial activity, and apoptotic changes were assessed. Differences were considered statistically significant at p < 0.05.
Results. A total of 125 COCs were recovered using the commercial medium and 121 using the experimental medium, with mean yields of 20.8 ± 3.6 and 20.5 ± 3.2 COCs per OPU procedure, respectively. Morphologically normal COCs accounted for 81.6% in the control group and 80.1% in the experimental group, with no statistically significant differences between the groups. After in vitro maturation, the proportion of oocytes reaching metaphase II and the presence of the meiotic spindle were comparable between groups. No significant differences were detected in cumulus morphology, ROS levels, mitochondrial activity, or apoptotic changes. The proportion of oocytes with high mitochondrial activity was 76.4% in the control group and 74.2% in the experimental group.
Conclusion. The newly developed domestic aspiration medium demonstrated biological efficacy comparable to that of the commercial medium and maintained the morphological quality, nuclear maturation, mitochondrial activity, and overall viability of bovine oocytes. These findings indicate that the medium is promising for further evaluation in OPU and in vitro embryo production. However, validation in a larger number of donor animals, including assessment of fertilization, cleavage, blastocyst development, embryo transfer, and pregnancy outcomes, is required before conclusions can be drawn regarding its broader practical application.