Establishment of conditions for ovum pick up and IVM of jennies oocytes toward the setting up of efficient IVF and in vitro embryos culture procedures in donkey (Equus asinus).

This research presents the establishment of the in vitro (test tube) production method of donkey embryos, a critical feat given the threatened state of various domestic and wild donkey breeds. From ovum pick up (OPU) to In vitro maturation (IVM), In vitro fertilization (IVF), and finally, the in vitro culture of zygotes, the study shows progress in donkey embryo production, suggesting further investigations to enhance the efficiency of the process.

Objective of the research

• Given that in vivo (within the living body) embryo production in equids (a family that includes horses and donkeys) is limited, the researchers aimed to establish conditions for in vitro embryo production in donkeys.

Methodology

• The first step involved collecting donkey cumulus-oocyte complexes (COCs) through transvaginal ultrasound-guided aspirations OPU from adult cyclic donkeys.
• These collected COCs were then subjected to in vitro maturation in a specific medium for different time lengths.
• This was followed by a preincubation period with oviductal fluid for thirty minutes, then a coincubation period with frozen-thawed donkey semen treated with a substance called procaine for eighteen hours.
• Culture incubation for 30 hours in a specific medium followed the procedural steps above.
• In total, five OPU sessions resulted in 92 COCs collected from 193 follicles with an average of 4.2 COCs per donkey.

Findings and Conclusions

• All the COCs expanded after over 24 hours of in vitro maturation. Metaphase 1 oocytes were observed after 30 hours in vitro maturation and 44% of them reached Metaphase 2 after 34 hours.
• However, only 15% of these oocytes contained two pronuclei after coincubation with donkey spermatozoa, with none of them developing further after 48 hours post-IVF. Some parthenogenetic activation was observed, suggesting that procaine may be ineffective for IVF treatment of donkey sperm.
• Nevertheless, the study has successfully established the conditions required for OPU in donkeys, achieving high recovery rates. The researchers also described for the first time the IVM chronology of donkey oocytes.
• Based on these findings, the experts recommend further studies to create more effective conditions for IVF and the development of donkey zygotes.