Multidimensional ejaculate-level variability in sperm quality in cynomolgus monkeys

Area of Science:

• Reproductive Biology
• Primate Research
• Spermatology

Background:

• Semen analysis is crucial for non-human primate management and research.
• Understanding ejaculate variability is key for accurate interpretation of male reproductive health.

Purpose of the Study:

• To characterize the variability of sperm quality across repeated ejaculates in cynomolgus monkeys.
• To assess the concordance of different semen parameters and their implications for reproductive status.

Main Methods:

• Collected repeated semen samples from individual cynomolgus monkeys.
• Evaluated samples using conventional semen analysis, computer-assisted sperm analysis (CASA), and functional assessments (viability, morphology, acrosome integrity/reaction).

Main Results:

• Observed substantial variability in progressive motility and sperm concentration across ejaculates.
• Found independent variation in kinematic parameters (e.g., amplitude of lateral head displacement) and motility percentages.
• Noted stable viability and morphology but higher variability in acrosome-related parameters.

Conclusions:

• Sperm quality parameters in cynomolgus monkeys are multidimensional and ejaculate-dependent, not fixed individual traits.
• Variability across ejaculates suggests single-sample assessment may not fully represent male reproductive status.
• These findings highlight the need for careful consideration of ejaculate variability in primate reproductive studies.