豚精液の凍結保存に関する研究

Abstract

It was reported3, 4, 6) that boar spermatozoa were very sensitive to glycerol, so that glycerol should be used at low level as the freeze protective agent of boar semen. In the previous report2), it was suggested that rapid freezing and rapid thawing were necessary conditions when glycerol level was low. However, it is difficult to thaw the large volume of frozen semen rapidly. To solve this problem, aluminum which has good thermal conductivity was tried as a material of packaging container for freezing boar semen.Schematic representation of the aluminum foil and packaging container was presented in Figure 1. The package was stable against freezing and thawing process. Semen was frozen in the shape of thin plate, hence rapid thawing was expected ecause of its large surface area as well as the good thermal conductivity of aluminum.Semen was diluted with honey-yolk diluent1). Frozen semen was thawed at 38°C through the three experiments.In experiment 1, effects of aluminum packaging container on post thawing motility were examined comparing with glass ampule and pellet (Table 1). The samples (Al-package and glass ampule) were frozen with Linde BF-3R biological freezer. The post thawing motility of spermatozoa frozen in the aluminum package was superior to the glass ampule and as good as the pellet.In experiment 2, different freezing methods were compared (Table 2).The best result was obtained in the samples frozen by placing the aluminum package on horizontal dry ice.In experiment 3, the influences of semen volume in aluminum package on post thawing motility were examined (Table 3). The motility decreased as the volume of semen was increased.From these data it is concluded that aluminum package is available for the container of freezing boar semen.