The Relationship Between Sperm Concentration and Fertilization in vitro of Mouse Eggs

Abstract

A 300 fold range of epididymal sperm concentrations (0.3-90 x 10⁵/ml) has been tested to determine whether there is a relationship between sperm concentration and level of fertilization achieved in vitro of mouse eggs. While very low concentrations (0.3-1.25 x 10⁵/ml) resulted in relatively low fertilization (43-64 percent), those in the range of 2.5-90 x 10⁵/ml gave fertilization rates of 80-94 percent. Consistently high results were obtained with sperm counts above 30 x 10⁵/ml and there was no evidence of reduction in fertility with very high sperm concentrations. Likewise, no observable minimum was found; acceptable rates of fertilization were achieved with a mean sperm:egg ratio of 417:1.