The Efficacy of Glucose and Electrolyte Solutions in Preserving the Structure of Fowl Spermatozoa after Freezing and Thawing

HARRIS et al.1), observing ultrastructural changes in rapidly frozen fowl spermatozoa, noted destructive effects on the acrosome, the midpiece, and the cytoplasmic membrane. Similar ultrastructural damages were seen by BAKST and SEXTON2) in frozen-thawed fowl and turkey spermatozoa under transmission and scanning electron microscopes. However, they gave little information on the possible mechanisms causing these ultrastructural changes. In our previous studies on morphological cryoinjury in fowl3) and Muscovy-drake spermatozoa4), we found increased incidences of crooked-necked spermatozoa (CNS), which were damaged at the mid-piece, under the light microscope (LM) and of abnormal acrosomes under the scanning electron microscope (SEM) after the freeze-thawing procedure. In experiments on preservation of fowl spermatozoa (both in various isotonic solutions and in various diluents adjusted to different osmotic pressures) at 5•Ž for 24hr, we speculated that the increased incidence of CNS might be due to high concentration of chloride ion in the media and that the acrosomal damage might be caused by increased osmotic pressure of media during the freezing process5,6). In order to test our speculations, we conducted the present study, examining under LM and SEM unfrozen and frozen-thawed fowl spermatozoa which were suspended in various salt solutions or in a non-electrolyte (glucose) solution.