title: Supplemental effect of varying L-cysteine concentrations on the quality of cryopreserved boar semen.
abstract: Cryopreservation is associated with the production of reactive oxygen species, which leads to lipid peroxidation of the sperm membrane and consequently a reduction in sperm motility and decreased fertility potential. The aim of this study was to determine the optimal concentration of L-cysteine needed for cryopreservation of boar semen. Twelve boars provided semen of proven motility and morphology for this study. The semen was divided into four portions in which the lactose-egg yolk (LEY) extender used to resuspend the centrifuged sperm pellet was supplemented with various concentrations of L-cysteine to reach 0 mmol L(-1) (group I, control), 5 mmol L(-1) (group II), 10 mmol L(-1) (group III) and 15 mmol L(-1) (group IV). Semen suspensions were loaded in straws (0.5 mL) and placed in a controlled-rate freezer. After cryopreservation, frozen semen samples were thawed and investigated for progressive motility, viability using SYBR-14/EthD-1 staining and acrosome integrity using FITC-PNA/EthD-1 staining. There was a significantly higher (P < 0.01) percentage of progressive motility, viability and acrosomal integrity in two L-cysteine-supplemented groups (group II and group III) compared with the control. There was a biphasic effect of L-cysteine, with the highest percentage of progressive motility, viability and acrosomal integrity in group III. In conclusion, 5 or 10 mmol L(-1) was the optimum concentration of L-cysteine to be added to the LEY extender for improving the quality of frozen-thawed boar semen.
authors.affiliation: Semen Laboratory, Faculty of Veterinary Science, Mahidol University, Phuttamonthon, Nakorn-pathom 73170, Thailand. vskkk@mahidol.ac.th
authors.forename: Kampon
authors.initials: K
authors.lastname: Kaeoket
authors.forename: Panida
authors.initials: P
authors.lastname: Chanapiwat
authors.forename: Padet
authors.initials: P
authors.lastname: Tummaruk
authors.forename: Mongkol
authors.initials: M
authors.lastname: Techakumphu
mesh_terms: D000177:Acrosome / Q000187:drug effects; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation; D003545:Cysteine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects; D034421:Sus scrofa; D013552:Swine
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D003545:Cysteine