REVEALING SURFACE CHANGES ASSOCIATED WITH MATURATION OF RAM SPERMATOZOA BY CENTRIFUGAL COUNTERCURRENT DISTRIBUTION IN AN AQUEOUS 2-PHASE SYSTEM

Centrifugal counter-current distribution (CCCD) in an aqueous two-phas e system was used to detect changes associated with maturation of ejac ulated ram spermatozao. Spermatozoa obtained form three successive eja culates of rams maintained in abstinence for one, two and three days w ere fractionated by CCCD. The results show that these ejaculates are r elatively enriched in a cell population which presents a very high enh anced affinity to the lower dextran-rich phase. This cell population i s not associated with loss of acrosomal integrity. In addition, it ten ds to disappear with longer abstinence periods, or after successive ej aculations at the same abstinence period, strongly suggesting that it is composed of immature cells. Therefore, phase partitioning can detec t surface changes accompanying sperm maturation and offers a new possi bility for sperm quality analysis.