Issue |
Reprod. Nutr. Dev.
Volume 42, Number 3, May-June 2002
|
|
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Page(s) | 217 - 226 | |
DOI | https://doi.org/10.1051/rnd:2002020 |
Reprod. Nutr. Dev. 42 (2002) 217-226
DOI: 10.1051/rnd:2002020
Comparison between glycerol and ethylene glycol for the cryopreservation of equine spermatozoa: semen quality assessment with standard analyses and with the hypoosmotic swelling test
Roberto Mantovania, Ada Rotab, Maria Elena Falomob, Lucia Bailonia and Leila Vincentica Department of Animal Science, University of Padua, Agripolis, 35020 Legnaro (PD), Italy
b Department of Veterinary Clinical Sciences, University of Padua, Italy
c Department of Animal Pathology, Faculty of Veterinary Medicine, University of Turin, Italy
(Received 4 February 2002; accepted 21 May 2002)
Abstract
The aims of this study were to compare glycerol (G) at customary
concentrations and ethylene glycol (EG) as cryoprotectants for
stallion semen in a skimmed milk (SM) extender, to test
different EG concentrations and to compare the results of manual
and computerized analysis with the hypoosmotic swelling (HOS) test.
Ejaculates from two stallions were collected over 3 weeks
(6 ejaculates per stallion), diluted in a SM based extender,
divided into 4 fractions, centrifuged and diluted again to a
concentration of 100
10
6 mL
-1 progressive motile spermatozoa
(PMS) in addition with the cryoprotectant (3% G, 3% EG, 6% EG, 9% EG).
Sperm motility was assessed both by microscopy (in raw and frozen-thawed
semen immediately after thawing) and with an HTM-IVOS analyzer
(Hamilton-Thorne Research, MA, USA), at 0, 1, 4, 6, and 12 h after
thawing and storage at 21 °C. Raw and frozen-thawed (0 h) semen
samples for G and EG at 3% were also submitted to the HOS test with
a 100 mOsm sucrose solution and were evaluated to detect the presence
of swollen tails. The higher EG concentrations (i.e. 6
significantly reduced the percentage of motile and PMS, immediately
after thawing. At the same concentration, i.e. 3%, G resulted in a
higher percentage of PMS than EG (36.2 vs. 30%,
P < 0.05), but at
12 h after thawing and storage at 21 °C, no significant differences
were detected between G and EG at 3%. The correlations between
progressive motility (assessed by direct microscope observation
or measured through the HTM analyzer) and the HOS test results
for 3%G and EG were
r = 0.61 and
r = 0.35, respectively. The HOS
test confirmed its suitability as a complementary method of analysis
for stallion semen. We conclude that with the SM extender used,
EG could substitute G as the cryoprotectant for stallion semen if
used at the same or lower concentration.
Key words: stallion / semen / cryoprotectant / glycerol / ethylene glycol
Correspondence and reprints: Roberto Mantovani
e-mail: roberto.mantovani@unipd.it
© INRA, EDP Sciences 2002