Benchmarks defining high-quality sperm in the common marmoset (Callithrix jacchus)

Area of Science:

• Primate reproductive biology
• Nonhuman primate models in biomedical research

Background:

• Common marmosets are valuable research models due to their small size and rapid reproduction.
• Assisted reproductive techniques (ART) are crucial for maximizing the utility of captive marmosets, including genetically modified individuals.
• Standardized methods for sperm manipulation, storage, and sharing are needed.

Purpose of the Study:

• To identify characteristics of high-quality marmoset semen samples.
• To validate a simple method for selecting high-quality sperm for assisted reproduction.

Main Methods:

• Computer-assisted sperm analysis (CASA) was used to evaluate sperm quality in 44 marmoset samples.
• The swim-up method was tested for its efficacy in selecting high-quality sperm.

Main Results:

• High-quality semen samples were defined by specific thresholds for volume (≥ 30 µL), sperm count (≥ 10^7/ejaculate), total motility (≥ 35%), and normal morphology (≥ 5%).
• Sperm selected using the swim-up method showed significantly improved progressive motility and normal morphology compared to unselected sperm.
• Statistically supported reference values were established for evaluating marmoset semen quality.

Conclusions:

• Robust reference values for marmoset semen analysis were established.
• A validated swim-up method aids in selecting optimal sperm for assisted reproduction.
• These standards will facilitate consistent practices for sharing marmoset sperm internationally for research and reproduction.