COMPARISON OF ASSESSMENT OF FOWL SPERM VIABILITY BY EOSIN-NIGROSIN AND DUAL FLUORESCENCE (SYBR-14 PI)/

The kinetics of fowl sperm viability/mortality following short-term an d long-term in vitro storage were studied using 2 different staining m ethods: eosin/nigrosin (observed under light microscopy) and SYBR-14/P I(dual fluorescence). Based on data obtained at 0, 30 min and at 2, 4 and 24 h (T0, T30, T2, T4, and T24) after in vitro storage (4 degrees C, agitated) of fresh or frozen-thawed semen, the dual association SYB R-14/PI was more effective than eosin/nigrosin (P<0.05) staining for t he detection of sperm viability/mortality at early stages (30 min) in nonfrozen ejaculates stored above 0 degrees C. In cryopreserved prepar ations, the 2 techniques were comparable for assessing viable spermato zoa immediately after thawing, but higher percentages (P<0.05) of nonv iable spermatozoa were detected by the SYBR-14/PI procedure for up to 4 h of in vitro storage post thawing (4 degrees C, agitated). Finally, comparable results were observed between the 2 techniques 24 h after beginning in vitro storage post thawing. It is concluded that the dual association SYBR-14/PI procedure is more effective (or, at least, mor e rapid) than eosin/nigrosin staining for the assessment of sperm viab ility/mortality in both fresh and cryopreserved samples of fowl semen. However. in the latter case, the thawing stage needs to be followed b y a period of in vitro storage lasting at least 4 h to allow for easie r discrimination between viable and nonviable populations of spermatoz oa; (C) 1998 by Elsevier Science Inc.