EFFECT OF BOVINE SPERM SEPARATION BY EITHER SWIM-UP OR PERCOLL METHODON SUCCESS OF IN-VITRO FERTILIZATION AND EARLY EMBRYONIC-DEVELOPMENT

Citation
Jj. Parrish et al., EFFECT OF BOVINE SPERM SEPARATION BY EITHER SWIM-UP OR PERCOLL METHODON SUCCESS OF IN-VITRO FERTILIZATION AND EARLY EMBRYONIC-DEVELOPMENT, Theriogenology, 44(6), 1995, pp. 859-869
Citations number
32
Categorie Soggetti
Veterinary Sciences
Journal title
ISSN journal
0093691X
Volume
44
Issue
6
Year of publication
1995
Pages
859 - 869
Database
ISI
SICI code
0093-691X(1995)44:6<859:EOBSSB>2.0.ZU;2-6
Abstract
The objectives of these experiments were to characterize separation of frozen-thawed bovine spermatozoa on a Percoll gradient and then to co mpare sperm separation by either a swim-up or Percoll gradient procedu re for the ability of spermatozoa to fertilize oocytes in vitro. The P ercoll gradient was a 45 and 90% discontinuous gradient. Initial exper iments found that centrifugation of semen on the Percoll gradient for 15 min at 700 g was sufficient to obtain optimal recovery of motile sp ermatozoa. Most of the nonmotile spermatozoa were recovered at the int erface of the 45 and 90% Percoll layers, while the motile spermatozoa were primarily in the sperm pellet at the bottom of the gradient. When frozen-thawed semen from each of 7 bulls was separated by swim-up, a mean+/-SEM of 9%+/-1 of the motile spermatozoa were recovered after th e procedure. In contrast, more spermatozoa were recovered after Percol l gradient separation (P<0.05), with 40%+/-4 of the motile spermatozoa recovered. The effect of separation procedure on in vitro fertilizati on found swim-up separated spermatozoa penetrated a mean+/-SEM of 74%/-5 of the oocytes, while fewer oocytes were penetrated by Percoll sep arated spermatozoa at 52%+/-8 (P<0.05). There was no effect of the sep aration procedure on the rates of polyspermy as measured by sperm/pene trated ova, with a mean+/-SEM of 1.25+/-.09 for swim-up separated sper matozoa and 1.14+/-.07 for Percoll separated spermatozoa (P>0.05). A c arry over of Percoll into the fertilization medium with the Percoll se parated spermatozoa was found not the cause for the decreased penetrat ion of oocytes by these spermatozoa. In 2 of 3 bulls tested, the decre ased penetration of oocytes by Percoll separated spermatozoa could be overcome by increasing the sperm concentration during fertilization fr om 1 x 10(6) to 5 x 10(6)/ml. When development of embryos fertilized b y either swim-up or Percoll separated spermatozoa was compared for the semen from 2 bulls, a difference in cleavage rate was found in favor of swim-up separated spermatozoa (P<0.05), but there was no effect of separation procedure on development (Day 7) to the morula + blastocyst or blastocyst stage (P>0.05). The disadvantages of the Percoll proced ure could easily be overcome and the procedure was faster and yielded a six-fold greater recovery of motile spermatozoa than the swim-up met hod.