In vitro fertilization and embryo development in the marmoset monkey (Callithrix jacchus)

Area of Science:

• Reproductive Biology
• Primate Research
• In Vitro Fertilization

Background:

• Oocyte maturity and preincubation time are critical factors influencing fertilization and early embryo development in assisted reproductive technologies.
• Marmoset monkeys are valuable models for human reproductive studies due to their physiological similarities.

Purpose of the Study:

• To investigate the impact of oocyte maturity and preincubation duration on fertilization and subsequent embryo development in vitro in marmoset monkeys.
• To determine optimal preincubation conditions for maximizing fertilization and developmental potential of marmoset oocytes.

Main Methods:

• Oocytes were aspirated from preovulatory marmoset follicles and graded for maturity (Grade I-IV) based on cumulus expansion.
• Oocytes were subjected to varying preincubation periods (2-5h, 9-11h, 21-29h) before insemination with epididymal spermatozoa.
• Fertilization rates, polyspermy, and subsequent embryo development in vitro were assessed.

Main Results:

• Overall fertilization rate was 82%, with 2.3% polyspermy. Fertilization was lowest in Grade IV oocytes (60%) and with short preincubation (2-5h, 53%).
• Fertilization rate increased to 92% with 21-29h preincubation. Embryo development correlated with preincubation time, not oocyte maturity.
• Oocytes preincubated for 2-5h resulted in significantly fewer cells per embryo (P < 0.001) and showed delayed cleavage (100%).

Conclusions:

• Preincubation time is a more significant factor than initial oocyte maturity for successful in vitro fertilization and embryo development in marmosets.
• Extended preincubation (21-29h) significantly enhances fertilization rates and promotes better embryo cell proliferation.
• Understanding these parameters is vital for improving in vitro fertilization protocols in non-human primates.