Objective evaluation of spermatozoa motility as influenced by fresh blood serum and normal saline

In order to investigate the effect of fresh blood serum and normal saline on the motility of ejaculated spermatozoa, semen samples were collected from 7 fertile males, aged 25-39 yrs. Each sample was divided into 5 aliquots: one aliquot remained undiluted, and fresh blood serum from fertile men and normal saline were added to the others to produce 1:1 and 3:1 dilutions. Spermatozoal motility was evaluated objectively, every hour and for 4 h after ejaculation, by the multiple exposure photography method. It was found that serum from fertile men as well as normal saline caused a significant increase of spermatozoal velocity. However, spermatozoal velocity under the influence of serum from fertile men changed with time in a different way than in the undiluted aliquot and those diluted with normal saline. Thus, the beneficial effect of fresh blood serum on spermatozoal velocity, cannot only be attributed to the lowering of seminal viscosity and the reduction of sperm concentration caused by dilution, but to various substances present in blood serum.