title: Addition of oxytocin to semen extender improves both sperm transport to the oviduct and conception rates in pigs following AI.
abstract: Oxytocin (OXT) contained in boar semen is known to produce uterine contraction; therefore, we hypothesized that the co-injection of OXT with sperm would improve artificial insemination (AI) using liquid or frozen-thawed boar sperm. We initially examined whether OXT added to semen extender improved sperm transport to the oviduct. Although the addition of OXT did not affect the fresh or frozen-thawed sperm motility or acrosomal integrity, it significantly increased the number of sperm in the oviduct at 6 h after AI injection with OXT, as compared with the control (P < 0.05). Moreover, some sperm were observed in the sperm reservoir of the isthmus in the OXT treatment group, whereas few sperm were observed in the control. When OXT was added to the semen extender immediately prior to AI, the conception rates were significantly higher in both fresh semen and frozen-thawed semen than in the control group (P < 0.05: liquid, 87.5% vs. 70.5%; frozen-thawed, 89.8% vs. 75.0%). From these results, we concluded that the addition of OXT to the semen extender assisted in sperm transportation from the uterus to the oviduct, which resulted in improved reproductive performance.
authors.affiliation: Smaller Livestock and Environment Section, Livestock Research Institute, Oita Prefectural Agriculture, Forestry and Fisheries Research Center, Bungo-ono, Oita, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Okazaki
authors.forename: Erena
authors.initials: E
authors.lastname: Ikoma
authors.forename: Tukasa
authors.initials: T
authors.lastname: Tinen
authors.forename: Teiichi
authors.initials: T
authors.lastname: Akiyoshi
authors.forename: Manabu
authors.initials: M
authors.lastname: Mori
authors.forename: Hisanori
authors.initials: H
authors.lastname: Teshima
mesh_terms: D000818:Animals; D015925:Cryopreservation; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D007315:Insemination, Artificial / Q000379:methods*; D008297:Male; D010057:Oviducts; D010121:Oxytocin / Q000008:administration & dosage* / Q000494:pharmacology*; D012662:Semen Preservation; D013076:Sperm Count; D013083:Sperm Transport / Q000187:drug effects*; D013268:Stimulation, Chemical; D013552:Swine / Q000502:physiology*; D014590:Uterine Contraction / Q000187:drug effects; D014599:Uterus
chemical_list: D010121:Oxytocin
keywords: artificial insemination; cryopreservation; oxytocin; pig; sperm