X-sperm enrichment of bovine semen by percoll density gradient method and its effect on fertility of semen, sex ratio and conception rate
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Date
2017-08
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present research work was conducted to investigate the effect of percoll density gradient method of X-sperm semen enrichment on fertility of semen, conception rate and sex ratio. Semen samples collected by artificial vagina method from two cross-bred bovine bulls with mass motility of
˃
+3 and progressive motility
˃
70% were considered for the study. Fresh semen was centrifuged twice in percoll density gradient medium composed of 90%, 70% and 50% percoll gradients with dense layer at bottom and lighter layer at top at 500xg for 15 minutes at 22-24ºC. X-spermatozoa enriched semen pellet after 2nd centrifugation was diluted in EYC dilutor and used for AI within 48 hours of semen collection. The effect of percoll density gradient on semen quality (fertility) was revealed by evaluating various seminal parameters like volume, pH, motility, viability, concentration, metabolic activity (MBRT), membrane integrity (HOST) and acrosomal integrity at three stages; before centrifugation (stage I), after 1st centrifugation (stage II) and after 2nd centrifugation (stage III) respectively. The pregnancy rate was detected at 45-60 days post AI. The sex of fetus was detected at 60-80 days post AI by locating the position of genital tubercle with the help of ultrasonography. There was non-significant (P
˃ 0.05) change observed in pH and mass motility of semen at all three stages. The volume, progressive motility, concentration and HOST reactive sperms significantly decreased at stage
ІІ
and stage
І ІІ
compared to stage І
with no significant difference between stage
ІІ and stage
ІІ І . The percent live
sperms were significantly (P<0.05) higher at stage І
compared to stage
ІІ
and stage
І ІІ . There was
also significant decrease (P<0.05) in percent live sperms at stage
ІІІ compared to stage
ІІ
. The
time taken to reduce methylene blue at stage
ІІ І and stage
ІІ
was significantly (P<0.05) higher
compared to stage І
. There was non-significant effect on percent of spermatozoa with intact acrosomal membrane and fully damaged acrosomal membrane at all three stages however, partially damaged acrosomal membrane sperms were significantly (P<0.05) decreased at Stage
ІІ
and Stage
ІІІ compared to Stage І
with non-significant difference found between stage
І І and
stage
І І І . The conception rate significantly (P<0.05) decreased with X-enriched semen compared to non-sexed liquid semen. However, it was significantly (P<0.05) higher compared to the conception rate with sexed semen from flow cytometry. The female sex ratio of calves significantly (P<0.05) increased to 66.66% with X- sperm enriched semen compared to the male percentage of 33.33% with sexed semen and female percentage of 46.15% with non-sexed semen. In conclusion, centrifugation of fresh bovine semen twice in percoll density gradient medium did not affect the sperm quality much but, resulted in decrease in conception rate as compared to nonsexed semen and deviation of 66.66% sex ratio towards female calves.
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