title: Improvement of boar sperm cryosurvival by using single-layer colloid centrifugation prior freezing.
abstract: The aim of this experimental study was to evaluate the effectiveness of sperm selection using single-layer centrifugation (SLC) prior to freezing on the sperm cryosurvival of boar ejaculates. Twenty-four sperm rich ejaculate fractions (SREF), collected from 24 boars (one per boar), were divided into two groups according to their initial semen traits: standard (n = 15) and substandard (n = 9). Semen samples from each SREF were split in two aliquots, one remained untreated (control samples) and the other was single-layer centrifuged (500 g for 20 min) using 15 mL of Androcoll-P Large (SLC samples). The yield of total, motile (assessed by CASA) and viable (cytometrically evaluated after staining with H-42, propidium iodide (PI) and FITC-PNA) sperm after SLC was higher (P < 0.05) in standard than substandard semen samples. The semen samples were cryopreserved using a standard 0.5-mL straw freezing protocol. Post-thaw sperm motility and viability (assessed at 30 and 150 min post-thawing) were higher (P < 0.05) in SLC than in control samples, regardless of the initial semen traits of the ejaculates. Additionally, thawed spermatozoa from SLC samples were more resistant (P < 0.05) to lipid peroxidation (BIOXYTECH MDA-586 Assay Kit) than those from control samples, regardless of the initial semen traits of the ejaculates. The SLC-treatment also influenced the functionality of thawed spermatozoa undergoing an in vitro capacitation process. The percentage of viable sperm showing high membrane fluidity (assessed with merocyanine 540) was lower (P < 0.05) in the SLC than in the control samples, regardless of the initial semen traits of the ejaculates. Thawed viable spermatozoa of SLC samples generated less (P < 0.05) reactive oxygen species (assessed with CM-H(2)DCFDA) than those of control samples in the substandard ejaculates. These findings indicate that the sperm selection before freezing using SLC improves the freezability of boar sperm.
authors: Department of Medicine and Animal Surgery, Faculty of Veterinary Science, University of Murcia, E-30100 Murcia, Spain.
authors: M J
authors: MJ
authors: Martinez-Alborcia
authors: J M
authors: JM
authors: Morrell
authors: I
authors: I
authors: Parrilla
authors: I
authors: I
authors: Barranco
authors: J M
authors: JM
authors: Vázquez
authors: E A
authors: EA
authors: Martinez
authors: J
authors: J
authors: Roca
mesh_terms: D000818:Animals; D002462:Cell Membrane; D002498:Centrifugation / Q000379:methods / Q000662:veterinary*; D003102:Colloids; D015925:Cryopreservation / Q000662:veterinary*; D005615:Freezing; D008297:Male; D008315:Malondialdehyde; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*
chemical_list: D003102:Colloids; D008315:Malondialdehyde