EVALUATION OF BOVINE SPERMATOZOAL MORPHOLOGIC FEATURES AFTER STAINING OR FIXATION

  • 1 January 1976
    • journal article
    • research article
    • Vol. 37  (9) , 1053-1057
Abstract
Two experiments were conducted to evaluate effects of 3 stains and 2 fixatives on morphologic features of bovine spermatozoa. In experiment 1, the morphologic features of acrosomes of raw and incubated, extended spermatozoa were evaluated after staining with Hancock''s, Blom''s or Wells-Awa''s stains or after fixation with buffered glutaraldehyde. Evaluations were done of stained smears by bright field microscopy and of fixed, unstained preparations, by differential interference contrast microscopy, using wet mounts. Raw semen samples from 1st ejaculates of 80 bulls were evaluated. The percentage of spermatozoa with intact acrosomes averaged 83.5% in unstained preparations fixed in glutaraldehyde, compared with averages of 68.1, 74.5 and 67.4% for smears stained with Hancock''s, Blom''s or Wells-Awa''s procedures (P < 0.01). Procedures preparing stained smears appeared to be detrimental to acrosomes. Although counts for other acrosomal abnormalities differed (P < 0.01) in each treatment, patterns were inconsistent. With incubated, extended spermatozoa from 57 bulls, glutaraldehyde-fixed, unstained samples had more (55%) intact acrosomes (P < 0.01) than did samples stained with Hancock''s or Blom''s procedures (24.0 and 34.7%, respectively), but the former were not significantly different from Wells-Awa-stained smears (49.3% intact acrosomes). In experiment 2, several morphologic characteristics of spermatozoa from 15 1st ejaculates of 7 bulls were evaluated after staining with Hancock''s or Blom''s stains or after fixation in buffered glutaraldehyde or buffered-formol saline fixatives. Higher counts (P < 0.01) of head abnormalities were found in wet, unstained fixed preparations (4.83, 4.47, 7.87 and 7.93%, respectively, for Hancock''s Blom''s, glutaraldehyde and formol saline methods). There were more (P < 0.05) separated heads on stained, dry smears (1.43, 1.23, 0.47 and 0.47%, respectively, for Hancock''s, Blom''s, glutaraldehyde and formol saline procedures). Fixation with buffered glutaraldehyde resulted in higher counts (P < 0.01) of proximal protoplasmic droplets (2.47, 1.03, 0.67 and 1.43%, respectively, for glutaraldehyde, Hancock''s, Blom''s and formol saline procedures). Although not significant, the same trend was observed for distal protoplasmic droplets. Spermatozoal morphologic features were relatively uniform in the middle 3rd of each prepared slide, whereas more (P < 0.01) separated heads and abnormal midpieces and feqer (P < 0.01) normal spermatozoa were observed on the end at which the smearing process was initiated. Location within slides did not influence evaluation of morphologic characteristics of spermatozoa in fixed, wet seminal preparations. Two morphologic examinations of the same samples were done 8 days apart; differences (P > 0.05) were not observed, with the exception of higher (P < 0.05) counts of distal protoplasmic droplets at the 2nd reading. Highest repeatabilities in evaluation of morphologic features were obtained by counting 400 spermatozoa on wet preparations of unstained, fixed semen samples and using differential interference phase contrast microscopy as compared to evaluation of stained, dry smears and using bright field microscopy. [Evaluation of spermatozoal morphologic features is a diagnostic aid in assessing a bull''s breeding soundness.].

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