title: In vitro and in vivo fertilization potential of cryopreserved spermatozoa from bull epididymides stored for up to 30 hours at ambient temperature (18 °C-20 °C).
abstract: The aims of this study were to compare the viability and in vivo and in vitro fertilization potential post-thaw sperm collected at different times postorchiectomy from bull epididymides (EP) at 18 °C to 20 °C, with those of semen collected by electroejaculation (EJ) from the same bulls. Semen samples were collected by EJ from 10 Zebu bulls and cryopreserved. A week later 20 epididymides from these bulls were obtained by orchiectomy and randomly divided into five groups (G) to be maintained at ambient temperature for 6, 12, 18, 24, and 30 hours before sperm recovery by retrograde flow. The sperm were cryopreserved, and post-thaw parameters were determined by both computer-assisted sperm analysis and morphologic analysis. In vitro fertilization of oocytes was performed to assess the cleavage rate, blastocyst rate, total number of cells, and hatching rate of embryos. The G30 sperm samples were also used for fixed time artificial insemination (FTAI) of Zebu heifers (n = 10). The results of post-thaw sperm viability showed that total and progressive motility and plasma membrane integrity were lower in sperm in which cryopreservation was delayed for 30 hours, showing a negative correlation of these parameters with delay before cryopreservation. In all groups, it was possible to obtain viable embryos, and embryos from G6 samples had more cells than the other groups. The greatest embryo production rates were observed in G6, G12 and G18 (27.2 to 32.2%) and it was significantly lower in G24 and G30 samples. For EJ, many individual variations were observed in embryo production potential between bulls. G30 samples, with only 5.2% of post-thaw progressive motility, were able to fertilize and produced a pregnancy. To the authors' knowledge, this is the first time in vitro embryos up to 8 days of development and a pregnancy after FTAI have been produced with sperm from bull epididymides that had been stored at 18 °C to 20 °C for up to 30 hours.
authors.affiliation: Department of Veterinary Medicine, Federal University of Paraná, Funcionários Street, 1540, 80035-050 Curitiba, Paraná, Brazil; Department of Technology, Postgraduate studies in Bioprocess Engineering and Biotechnology, Human and Animal Health, Federal University of Paraná, Curitiba, Parana, Brazil. Electronic address: melbertol@hotmail.com.
authors.forename: Melina Andrea Formighieri
authors.initials: MAF
authors.lastname: Bertol
authors.affiliation: Department of Veterinary Medicine, Federal University of Paraná, Funcionários Street, 1540, 80035-050 Curitiba, Paraná, Brazil; Department of Technology, Postgraduate studies in Bioprocess Engineering and Biotechnology, Human and Animal Health, Federal University of Paraná, Curitiba, Parana, Brazil.
authors.forename: Romildo Romualdo
authors.initials: RR
authors.lastname: Weiss
authors.affiliation: Department of Veterinary Medicine, Postgraduate studies in Animal Science, Pontifical Catholic University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: Luiz Ernandes
authors.initials: LE
authors.lastname: Kozicki
authors.affiliation: Department of Technology, Postgraduate studies in Bioprocess Engineering and Biotechnology, Human and Animal Health, Federal University of Paraná, Curitiba, Parana, Brazil.
authors.forename: Ana Claudia Machinski Rangel de
authors.initials: ACMR
authors.lastname: Abreu
authors.affiliation: Department of Veterinary Medicine, Postgraduate studies in Animal Science, Pontifical Catholic University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: João Filipi Scheffer
authors.initials: JFS
authors.lastname: Pereira
authors.affiliation: Department of Veterinary Medicine, Postgraduate studies in Animal Science, Pontifical Catholic University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: Jonathan Jesus
authors.initials: JJ
authors.lastname: da Silva
mesh_terms: D000818:Animals; D002417:Cattle; D015925:Cryopreservation / Q000662:veterinary*; D004822:Epididymis / Q000166:cytology*; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D007315:Insemination, Artificial / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D012662:Semen Preservation / Q000662:veterinary*; D013094:Spermatozoa / Q000502:physiology*; D013696:Temperature; D013997:Time Factors
keywords: Cryopreservation; Embryo; Epididymis; Fertilization; Sperm