Vitality and Acrosomal Integrity of Buffalo Spermatozoa Frozen in Straws Using Different Rates of Thawing

S. I. KOLEV

Buffalo Research Institute with Biotechnology Centre, BG-9700 Shoumen, Bulgaria

Abstract

KOLEV, S. I., 2000. Vitality and acrosomal integrity of buffalo spermatozoa frozen in straws using different rates of thawing. Bulg. J. Agric. Sci., 6: 477-480

The aim of the study was to determine the effect of different regimes of thawing on motility and acrosomal integrity of buffalo spermatozoa frozen in straws. Fifteen ejaculates from mature buffalo bulls – Bulgarian Murrah breed were tested. Semen was extended in PG₂₀ extender containing as exocryoprotector high molecular polyethylen glycol (kD 20000) and packaged in straws. After freesing and one year storage in liquid nitrogen at – 196 ⁰C semen was thawed at water bath temperatures of 30, 38 and 75 ⁰C for motility and acrosomal integrity. The thawing of spermatozoa at 38⁰C for 30 s resulted in higher % motility and intact acrosomes of spermatozoa while regime 38 ⁰C for 15 s was found to be the next in order of merit. Reduction of motility and percentage of intact acrosomes was most evident when spermatozoa were thawed at 75⁰C for 9 s.

Key words : spermatozoa, buffalo, thawing rate