Comparative Evaluation of Different Methods for Assessing Stallion Sperm Membrane Integrity

Abstract

Comparative evaluation of three different methods for assessing stallion sperm-membrane integrity, including the eosin staining technique, the fluorochrome staining (SYBR-14 + PI) method, and the hypo-osmotic test, has been made in order to reveal the most efficient method of measurement for this item. The stallion sperm showed high coefficients of correlation between sperm motility and intact membrane proportion with all the methods of measurement. The best coincidence result was attained with the eosin staining technique, assessed by a correlation coefficient of 0.91. This technique has the advantages of simplicity, accessibility, and efficiency. Accurate assessment requires performing a method of subtracting a number of unstained damaged sperm cells, which are nonfunctional, from a total number of unstained spermatozoa. The proportion of motile sperm does not coincide with the proportion of sperm intact membranes during the stallion-semen storage process according to all the methods of measurement. A significant sperm count remains with intact cell membranes at the loss of total motility at the end of a storage process. This indicates that the sperm cells become immotile because of layout of the energetic material in flagellar mitochondria, which is not associated with membrane integrity. Therefore, it is recommended to assess the stallion sperm membranes with the use of fresh or thawed sperm. It is suggested to use assessment of membrane integrity in clarifying the sperm motility, particularly, in especially doubtful cases.