The hypo-osmotic swelling test : an assay of cell membrane integrity and quality of frozen thawed buffalo semen

Abstract

Frozen-thawed semen from IO buffalo bulls was subjected to hypo-osmotic swelling test (HOSn by
incubating for 60 minutes at 37°C in a fructose/sodium citrate solution with an osmolarity of 100 mOsm kg-1• On
examination with a phase-contrast microscope (x400), a proportion of cells with intact membranes were found
swollen characterized by bending, coiling or shortening of the tail. Some of these cells showed non-progressive
flickering of the middle piece. Of the 10 :bulls, one which had the lowest mean value for swollen spermatozoa
following HOST also had the lowest fertility. It is concluded that the HOST could be useful in evaluating fertility
of buffalo bulls in conjuction with other semen analysis parameters. Further studies should involve separate
assessment of both inactive and active swollen cells and their relationship to fertility.