Time-lapse imaging and developmental competence of donkey eggs after ICSI: Effect of preovulatory follicular fluid during oocyte in vitro maturation.

This research explores the effect of using preovulatory follicular fluid (PFF) during the in vitro maturation of donkey (jenny) eggs, specifically in relation to their maturation rate, cell expansion and embryo development after Intracytoplasmic Sperm Injection (ICSI). The study found that supplementing the maturation process with donkey PFF or fetal bovine serum (FBS) supports nuclear maturation and early preimplantation embryo development.

Objective of the Research

• The objective of this study was to examine the impact of supplementing in vitro maturation with preovulatory follicular fluid (PFF) obtained from female donkeys (known as jennies) on the developmental competence of donkey eggs.
• The researchers aimed to test whether the practice could increase the success rate of the in vitro maturation process, with a focus on nuclear maturation rates, cumulus cell expansion, and post-ICSI embryo development.
• Underpinning the research is the increasing importance of assisted reproductive technologies in maintaining the genetic diversity of donkey species and breeds, some of which are considered endangered.

Methodology

• The researchers compared the effects of using fetal bovine serum (FBS) and donkey PFF during in vitro maturation.
• Time-lapse imaging was conducted following the ICSI of donkey and horse oocytes.
• The team conducted eight ovum pick-up sessions from five jennies, yielding a total of 45 cumulus-oocyte complexes (COCs).

Findings

• Contrary to their hypothesis, the researchers found that donkey COCs matured in culture media supplemented with either FBS or donkey PFF showed no significant differences in nuclear maturation rates and early preimplantation embryo development post-ICSI.
• While the cumulus cells of the PFF group showed lower expansion, this did not seem to affect overall maturation and development.
• ICSI embryos from donkeys exhibited similar morphokinetics to those extracted from horses after ICSI.

Significance

• This study is the first to report on ICSI, time-lapse imaging and in vitro blastocyst production in the donkey.
• The findings suggest that both FBS and donkey PFF can effectively supplement the in vitro maturation process, offering potential routes to preserving the genetic diversity of threatened donkey species and breeds.