219. Prevalence of sperm chromatin instability amongst bulls in a subtropical environment: a preliminary investigation
K. J. Hengstberger A , D. Sester B , D. Tutt C , R. G. Holroyd D , G. Fordyce D , S. D. Johnston A and M. J. D’Occhio AA School of Animal Studies, The University of Queensland, Gatton, QLD, Australia
B School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
C School of Molecular and Microbial Studies, The University of Queensland, St Lucia, QLD, Australia
D Queensland Department of Primary Industries and Fisheries, Rockhampton, QLD, Australia
Reproduction, Fertility and Development 17(9) 84-84 https://doi.org/10.1071/SRB05Abs219
Submitted: 26 July 2005 Accepted: 26 July 2005 Published: 5 September 2005
Abstract
During mammalian spermiogenesis nucleosomal histone proteins bound to DNA are replaced by protamines. The integrity and stability of the protamine-DNA association in sperm can be measured using the sperm chromatin structure assay (SCSA). The recent emergence of compelling information from assisted reproduction in humans of a relationship between sperm chromatin stability and the establishment and maintenance of pregnancy has led to considerable interest in production and recreational animals.1 The aim in the present study was to determine the incidence of sperm chromatin instability amongst bulls in a subtropical region of northern Australia, as a first step in evaluating whether sperm chromatin instability is a contributing factor to reproductive wastage in cattle. Semen was obtained from 565 Bos indicus and Bos indicus x taurus bulls from northern and central Queensland aged between 20 months and 10 years. Samples were subjected to standard semen evaluation2 and aliquots stored in liquid nitrogen until chromatin integrity was determined using the SCSA.3 Samples exposed to the SCSA for 0.5 min revealed 4.9% of bulls had a DFI >27% and this increased to 11.5% of bulls with DFI >27% when samples were exposed to the SCSA for 5 min. DFI was significantly correlated with sperm density, mass activity, motility and morphology. Location appeared to have a greater influence on DFI than genotype. Preliminary data from a small sample of bulls would suggest that a relatively high DFI can be repeatable for individual bulls. These findings indicate that sperm chromatin instability occurs in bulls in northern Australia although the prevalence might be considered to be relatively low. The relationship of sperm chromatin instability to the contribution of bulls to embryonic mortality requires further study and likewise the impact on reproductive wastage remains to be determined.
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(2) Fitzpatrick LA et al. (2002). Anim. Reprod. Sci. 71, 39.
(3) Evenson D and Jost L (2000). Methods Cell Sci. 22, 169.
