Effects of Addition of Seminal Plasma to Semen Diluent on the Post-Thaw Motility and Abnormality of Cock Spermatozoa

Abstract

The present study was undertaken to examine the possibility that the seminal plasma might protect cock spermatozoa against damage during freezing and thawing.Semen was collected from 15 cocks by the method of abdominal massage and pooled. The pooled semen was diluted 1:3 with 5.7% glucose solution (supplemented 7% glycerol in the final concentration) containing egg yolk, seminal plasma or components of seminal plasma. The diluted semen was frozen using the pellet method and thawed at 37°C. Motility was scored from 0 to 5.The result obtained are as follows.1) The motility of spermatozoa frozen and thawed in the diluent with 15% egg yolk was similar to that in the diluent with 15% seminal plasma but significantly greater than that of the control frozen and thawed in the 5.7% glucose solution. The abnormality of spermatozoa frozen and thawed in the diluent with 15% egg yolk tended to be higher than when the diluent with 15% seminal plasma or the 5.7% glucose solution was used.2) Addition of low molecule fraction (M.W. 10, 000) from seminal plasma at any concentration used, the post-thaw motility of spermatozoa was markedly higher than the control and the abnormality of the frozen-thawed spermatozoa was significantly lower than the control.4) These results suggest that the addition of cock seminal plasma to diluents might exert more protective effect to the cock spermatozoa than addition of egg yolk during freezing and thawing, and that the favorable factor was included in the macromolecule fraction in seminal plasma.