MEASUREMENT OF THE SPERM MOTILITY INDEX VIA THE SPERM QUALITY ANALYZER AND ITS RELATIONSHIP TO OTHER QUALITATIVE SPERM PARAMETERS

Sperm parameters such as the concentration and percentage of motile sp ermatozoa are commonly used to assess semen quality. The sperm quality analyzer (SQA) is a device that detects variations in the optical den sity of motile spermatozoa, providing a sperm motility index (SMT) tha t is based on various sperm parameters including the concentration, mo rphology and acrosomal status of motile spermatozoa. The relationship between SMI values of frozen-thawed bovine spermatozoa undergoing swel ling in a hypoosmotic medium (100 mOsm/L) and other sperm parameters w ere evaluated. Frozen semen specimens from 3 bulls were thawed and was hed with Ham's F-10 supplemented with 3% BSA and split into 3 (0.2 mL) aliquots. The aliquots were diluted with 1.0 mL of Ham's F-10 (Aliquo t 1), isotonic sodium citrate (Aliquot 2), and hypotonic sodium citrat e (Aliquot 3). The osmotic pressure of the media used for dilution of Aliquots 1 and 2 was 300 mOsm/L, while that for Aliquot 3 was 100 mOsm /L. Following dilution, the aliquots were incubated for 30 min and man ually assessed at 5-min intervals for the percentage and grade of moti lity (Grades 0 to 4) as well as for the percentage of swollen spermato zoa. Sperm samples were simultaneously evaluated by SQA to obtain the SMI values at the same 5-min intervals during the 30-min incubation. S ignificant correlations were observed between SMI values and other spe rm parameters in Aliquot 3 (P<0.05). The results indicated that the SM I values obtained from frozen-thawed bovine spermatozoa exposed to a 1 00 mOsm/L diluent, which causes optimal swelling of spermatozoa, are h ighly correlated to other sperm parameters. The SQA unit, as applied i n this study, can be used for rapid and reliable screening of sperm sa mples.