SELECTION OF BOVINE SPERMS FROM FROZEN-TH AWED SEMEN - COMPARISON OF 2 METHODS

The evaluation of methods for gamete selection is very important for i n vitro fertilization (IVF). Regarding the male gamete, a population o f viable, motile and normal spermatozoa free from seminal plasma conta minants must be selected. The objective of this study was to compare t wo sperm selection methods: repeated washing-centrifugation (LC) and m igration-sedimentation (MS). Frozen-thawed semen was used for all assa ys (n = 8). in aliquots, simultaneously for each technique. The basic medium utilized was described by Brackett and Oliphant, 1975 (BO). Aft er each method, sperms were assessed through the triple staining techn ique. Results obtained show that there are statistically significant d ifferences between MS and LC regarding motility: 68.3% vs 46.7% (p < 0 .05); viability: 74.6% vs 54.0% (p < 0.05); functional integrity: 67.8 % vs 52.5% (p < 0.05), and normal morphology: 98.5% vs 86.5% (p < 0.05 %). These results show that MS optimizes the selection of sperm cells.