Individual variability in post-thaw sperm survival in a captive koala population

Zee, Y. P., Holt, W. V., Nicolson, V., Pyne, M. and Johnston, S. D. (2009) Individual variability in post-thaw sperm survival in a captive koala population. Cryobiology, 59 1: 69-74. doi:10.1016/j.cryobiol.2009.04.010


Author Zee, Y. P.
Holt, W. V.
Nicolson, V.
Pyne, M.
Johnston, S. D.
Title Individual variability in post-thaw sperm survival in a captive koala population
Journal name Cryobiology   Check publisher's open access policy
ISSN 0011-2240
Publication date 2009-08-01
Sub-type Article (original research)
DOI 10.1016/j.cryobiol.2009.04.010
Open Access Status
Volume 59
Issue 1
Start page 69
End page 74
Total pages 6
Editor David E Pegg
Place of publication United States
Publisher Academic Press
Language eng
Subject C1
969999 Environment not elsewhere classified
060803 Animal Developmental and Reproductive Biology
Abstract This study documented the extent of individual animal variation with respect to two proven methods of sperm cryopreservation in a captive population of 22 koalas. Semen samples were collected by electroejaculation, diluted in Tris-citrate glucose and equilibrated to 4 °C before being further diluted and frozen in media containing a final concentration of either 14% (v/v) glycerol or 12.5% (v/v) dimethylacetamide (DMA). There were significant differences in post-thaw survival of spermatozoa from different animals that were independent of pre-freeze semen quality. Glycerol proved to be a better cryoprotectant than DMA in terms of maintaining motility, plasma membrane integrity and high mitochondrial membrane potential; however, there was no difference between cryoprotectants with regards to their ability to prevent chromatin relaxation. While a positive correlation was observed between motility and mitochondrial membrane potential, both before and after cryopreservation, the slopes of the pre-freeze regression lines of these relationships were significantly altered following cryopreservation, suggesting that the efficiency of energy generation by the mitochondria was lowered by the freeze-thaw process. Based on a cluster analysis of the post-thaw semen viability parameters, the koalas in this study could be divided into two distinct groups; Cluster 1 had significantly higher sperm viability compared to the other cluster, regardless of the cryoprotectant used. The unpredictability of assessing post-thaw survival from pre-freeze koala semen parameters requires further investigation but is likely to be associated with variation in ejaculate composition or inherent genetic differences between animals.
Keyword Marsupial
Phascolarctos-cinereus spermatozoa
MMP
Mitochondria
ATP
Cryodamage
Cryo-sensitivity
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
 
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Created: Thu, 03 Sep 2009, 17:48:10 EST by Mr Andrew Martlew on behalf of School of Animal Studies