title: Increasing storage time of extended boar semen reduces sperm DNA integrity.
abstract: There is an extensive use of artificial insemination (AI) in the pig industry. Extended liquid boar semen may be used for insemination for up to 5 days after collection. The objective of this study was to determine the changes in sperm quality, when boar semen was extended and stored at 18 degrees C for up to 72 h post-collection. The study included three ejaculates from five boars, for each of the four breeds: Duroc, Hampshire, Landrace and Danish Large White (n=60 ejaculates). The sperm chromatin structure assay (SCSA) showed an increase in DNA fragmentation index (DFI) after 72 h of incubation (P<0.001), with no differences between breeds (P=0.07). For two Hampshire boars, all ejaculates had a large increase in DFI after 24 h of incubation. The standard deviation of DFI (SD-DFI) differed between breeds, with the SD-DFI for Hampshire being significantly greater than for the other breeds. The SD-DFI did not change during the 72 h of storage. Sperm viability was determined using SYBR-14 and propidium iodide in combination with flow cytometry. The sperm viability did not differ between breeds (P=0.21), but a difference in viability during storage (P<0.001) was detected. In conclusion, the SCSA cytogram patterns were consistent for different ejaculates within boars and storage of extended boar semen at 18 degrees C for 72 h significantly decreased the integrity of sperm DNA.
authors.affiliation: Department of Large Animal Sciences, Veterinary Reproduction and Obstetrics, The Royal Veterinary and Agricultural University, Dyrlaegevej 68, 1870 Frederiksberg C, Denmark. gbh@kvl.dk
authors.forename: Gry B
authors.initials: GB
authors.lastname: Boe-Hansen
authors.forename: Annette K
authors.initials: AK
authors.lastname: Ersbøll
authors.forename: Torben
authors.initials: T
authors.lastname: Greve
authors.forename: Preben
authors.initials: P
authors.lastname: Christensen
mesh_terms: D000165:Acridine Orange / Q000737:chemistry; D000818:Animals; D002843:Chromatin / Q000502:physiology; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D004247:DNA / Q000502:physiology*; D005434:Flow Cytometry / Q000662:veterinary; D005456:Fluorescent Dyes / Q000737:chemistry; D008297:Male; D009930:Organic Chemicals; D012661:Semen / Q000502:physiology*; D012662:Semen Preservation / Q000009:adverse effects / Q000662:veterinary*; D013076:Sperm Count / Q000662:veterinary; D013094:Spermatozoa / Q000502:physiology*; D018709:Statistics, Nonparametric; D013552:Swine / Q000502:physiology*
chemical_list: D002843:Chromatin; D005456:Fluorescent Dyes; D009930:Organic Chemicals; C093207:SYBR-14; D004247:DNA; D000165:Acridine Orange