title: Relationship between non-return rate and chromatin condensation of deep frozen bull spermatozoa.
abstract: This study analyzes the relationship between chromatin condensation and field fertility, expressed as 90 days non-return rate (NRR), of bulls actively used by AI studs. Frozen-thawed semen from five bulls (six ejaculates per bull, three straws per ejaculate), that showed a non-return rate between 60 and 80%, were analyzed to assess sperm chromatin condensation and stability. The chromatin condensation was determined by flow cytometry using propidium iodide as fluorochrome, and the chromatin stability was evaluated by inducing its decondensation with SDS and EDTA. Coefficient of variation among replicates was less than 7% and 5% for chromatin condensation and stability, respectively. No correlation was present between chromatin condensation and NRR. However, significant correlation was found between chromatin stability and NRR. Chromatin stability was higher (P < 0.05) in those bulls that showed higher fertility. The results obtained in this study conclude that assessment of stability could be a valuable tool for routine evaluation and identification of ejaculates with high levels of sperm chromatin abnormalities and to detect animals of higher reproductive potential.
authors.affiliation: Departamento de Reproducción Animal, INIA, Ctra dela Coruña Km 5,9, Madrid 28040, Spain.
authors.forename: Ninoska
authors.initials: N
authors.lastname: Madrid-Bury
authors.forename: José Félix
authors.initials: JF
authors.lastname: Pérez-Gutiérrez
authors.forename: Sonia
authors.initials: S
authors.lastname: Pérez-Garnelo
authors.forename: Pedro
authors.initials: P
authors.lastname: Moreira
authors.forename: Belén
authors.initials: B
authors.lastname: Pintado Sanjuanbenito
authors.forename: Alfonso
authors.initials: A
authors.lastname: Gutiérrez-Adán
authors.forename: Julio
authors.initials: J
authors.lastname: de la Fuente Martínez
mesh_terms: D000818:Animals; D002417:Cattle; D002843:Chromatin / Q000187:drug effects / Q000648:ultrastructure*; D015925:Cryopreservation / Q000662:veterinary*; D004492:Edetic Acid / Q000494:pharmacology; D005298:Fertility; D005434:Flow Cytometry / Q000662:veterinary; D005456:Fluorescent Dyes; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D011419:Propidium; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013094:Spermatozoa / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D002843:Chromatin; D005456:Fluorescent Dyes; D011419:Propidium; D012967:Sodium Dodecyl Sulfate; D004492:Edetic Acid