Assisted oocyte activation.

OBJECTIVE: Currently, there is a rapid increase in studies on assisted oocyte activation, which can significantly improve the process of in vitro fertilization. Fertilization of oocytes by conventional methods and by intracytoplasmic sperm injection can be affected by insufficient activation of the oocyte. The reason is mainly deviations in the enzymatic equipment of sperm or oocytes or a non-functional activation cascade. In many cases, fertilization can be achieved using artificial oocyte activation by applying calcium ion donors to the oocytes after sperm microinjection. However, opinions on the safety and reliability of this method are not uniform. The aim of the thesis is to present current knowledge about assisted oocyte activation and its impact not only on in vitro fertilization, but also on subsequent embryonic and fetal development. METHODOLOGY: Research of relevant literature in Web of Science, PubMed/Medline and Scopus databases. RESULTS AND CONCLUSIONS: Based on the literature data and the authors' own experience, it follows that this method is effective and safe from the point of view of further development of the embryo, fetus and postnatal development. Extensive meta-analyses focused on this method were carried out, which did not find a negative impact not only on the embryonic and fetal development of the individual, but this method did not have associated with a negative impact on the psychosomatic development of the children.

Glutathione during Post-Thaw Recovery Culture Can Mitigate Deleterious Impact of Vitrification on Bovine Oocytes.

Vitrification of bovine oocytes can impair subsequent embryo development mostly due to elevated oxidative stress. This study was aimed at examining whether glutathione, a known antioxidant, can improve further embryo development when added to devitrified oocytes for a short recovery period. Bovine in vitro matured oocytes were vitrified using an ultra-rapid cooling technique on electron microscopy grids. Following warming, the oocytes were incubated in the recovery medium containing glutathione (0, 1.5, or 5 mmol L-1) for 3 h (post-warm recovery). Afterwards, the oocytes were lysed for measuring the total antioxidant capacity (TAC), activity of peroxidase, catalase and glutathione reductase, and ROS formation. The impact of vitrification on mitochondrial and lysosomal activities was also examined. Since glutathione, added at 5 mmol L-1, significantly increased the TAC of warmed oocytes, in the next set of experiments this dose was applied for post-warm recovery of oocytes used for IVF. Glutathione in the recovery culture did not change the total blastocyst rate, while increased the proportion of faster developing blastocysts (Day 6-7), reduced the apoptotic cell ratio and reversed the harmful impact of vitrification on the actin cytoskeleton. These results suggest that even a short recovery culture with antioxidant(s) can improve the development of bovine devitrified oocytes.

Relationship between the animal body condition and reproduction: the biotechnological aspects.

The aim of this review was to evaluate the relationship between the body condition of cows and reproduction. Reproduction was evaluated from the viewpoint of animal husbandry traits, ovarian activity and embryo transfer. Main emphasis was given to the review of articles from the area of biotechnical methods (in vitro embryo production, embryo transfer). Most authors agree on the opinion that the worsening of the reproduction traits of cows is a result of changes in the body condition score (BCS) either under or over their average value. Worsening of reproduction traits was presented not only from a zootechnical viewpoint (e.g., calving interval, 56 d nonreturn rate, etc.) but also in term of ovarian activity, oocyte recovery and in vitro embryo production. In general, the body condition of cows is an important factor affecting female reproduction ability at the ovarian level.