Boar Fertility and Sperm Chromatin Structure Status

Date: 5-28-2009

Didion BA, Kasperson KM, Wixon RL, Evenson DP. . J Androl. 2009 May 28. [Epub ahead of print

CAPSULE: Pig sperm DNA fragmentation rate is highly correlated with pregnancy rate AND the number of pigs born per litter.  This animal model system suggests that not only does an increased level of sperm DNA fragmentation reduces the pregnancy rate but also that DNA fragmentation causes early embryo death as has been observed in humans. 

Little information exists about boar sperm chromatin quality and fertility within a commercial setting. The objective of this report is to provide information about boar sperm chromatin integrity and its relationship to fertility. The Sperm Chromatin Structure Assay (SCSA) was used retrospectively to characterize sperm from 18 sexually mature boars having fertility information. Boar fertility was defined by farrowing rate (FR) and average total number of pigs born (ANB) per litter of gilts and sows mated to individual boars. Fertility data was compiled for 1867 matings across the 18 boars. The SCSA uses flow cytometry to evaluate the structural integrity of sperm nuclear DNA. The SCSA parameters measured in this retrospective analysis were the %DNA Fragmentation Index (%DFI) and Standard Deviation of DFI (SD DFI). The %DFI and SD DFI showed the following significant negative correlations with FR and ANB; %DFI vs. FR r = -0.55, p<0.01; SD DFI vs. FR r = -0.67, p<0.002; %DFI vs. ANB r = -0.54, p<0.01; and SD DFI vs. ANB r = -0.54, p<0.02. Although more information is required to better understand the relationship between DFI and boar fertility, this report suggests that the SCSA assay may be an important assay for identification of boars having potential for lowered fertility

DPE: this animal model is shown here because of the importance of sperm DNA fragmentation seen in a multiparous animal resulting not only in a lower pregnancy rage but a lower number of pigs/litter.  It is suggested that eggs were fertilitized by normal and DFI high sperm and the latter resulting in embryo deaths.  This can be related to human fertilization, embryo transfer and resulting embryo death due to damaged sperm DNA.