Comparison of the longevity of motility of stallion spermatozoa incubated at 38 degrees C in different capacitating media and containers

This study was designed to compare the effects of different media and containers on longevity of motility of spermatozoa during in vitro incubation at 38 degrees C in either air or 5% CO2 atmosphere. Three ejaculates were collected from each of 4 stallions. The media tested were skim milk-glucose, modified Krebs/Ringer and Hank's salts solution for incubation in an air atmosphere, and modified Krebs/Ringer and Brackett and Oliphant (BO) defined medium for incubation in a 5% CO2 atmosphere. All samples were incubated in 5-mL borosilicate glass tubes filled with 3 mL of extended spermatozoa, 5-mL borosilicate tubes filled with 6 mL (topped) of extended spermatozoa, 35-mm Petri dishes filled with 3 mL of extended spermatozoa, and 35-mm Petri dishes with 200-microL microdroplets of extended spermatozoa under sterile mineral oil. For all treatments, individual samples were removed at 2, 4, 6 and 12 h of incubation to determine the percentage of motile cells. Overall, spermatozoa incubated in Petri dishes in both 3-mL and microdroplet treatments had significantly higher motility than those incubated in glass tubes (P<0.01). At 6 and 12 h of incubation in Petri dishes, progressive motility was significantly higher for spermatozoa extended in the Hank's salts solution than in the other media. Both the medium and container used significantly affected the longevity of motility of spermatozoa incubated at 38 degrees C.