title: Sperm sex-sorting and preservation for managing the sex ratio and genetic diversity of the southern white rhinoceros (Ceratotherium simum simum).
abstract: White rhinoceros ejaculates (n=9) collected by electroejaculation from four males were shipped (10°C, 12h) to develop procedures for the production of chilled and frozen-thawed sex-sorted spermatozoa of adequate quality for artificial insemination (AI). Of all electroejaculate fractions, 39.7% (31/78) exhibited high quality post-collection (≥70% total motility and membrane integrity) and of those, 54.8% (17/31) presented reduced in vitro quality after transport and were retrospectively determined to exhibit urine-contamination (≥21.0μg creatinine/ml). Of fractions analyzed for creatinine concentration, 69% (44/64) were classified as urine-contaminated. For high quality non-contaminated fractions, in vitro parameters (motility, velocity, membrane, acrosome and DNA integrity) of chilled non-sorted and sorted spermatozoa were well-maintained at 5°C up to 54h post-collection, whereby >70% of post-transport (non-sorted) or post-sort (sorted) values were retained. By 54h post-collection, some motility parameters were higher (P<0.05) for non-sorted spermatozoa (total motility, rapid velocity, average path velocity) whereas all remaining motion parameters as well as membrane, acrosome and DNA integrity were similar between sperm types. In comparison with a straw method, directional freezing resulted in enhanced (P<0.05) motility and velocity of non-sorted and sorted spermatozoa, with comparable overall post-thaw quality between sperm types. High purity enrichment of X-bearing (89±6%) or Y-bearing (86±3%) spermatozoa was achieved using moderate sorting rates (2540±498X-spermatozoa/s; 1800±557Y-spermatozoa/s). Collective in vitro characteristics of sorted-chilled or sorted-frozen-thawed spermatozoa derived from high quality electroejaculates indicate acceptable fertility potential for use in AI.
authors.affiliation: SeaWorld and Busch Gardens Reproductive Research Center, SeaWorld Parks and Entertainment, 2595 Ingraham St, San Diego, CA 92109, USA. Electronic address: justine.obrien@seaworld.com.
authors.forename: J K
authors.initials: JK
authors.lastname: O'Brien
authors.affiliation: Center for Conservation and Research of Endangered Wildlife, Cincinnati Zoo and Botanical Garden, Cincinnati, OH 45220, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Roth
authors.affiliation: Center for Conservation and Research of Endangered Wildlife, Cincinnati Zoo and Botanical Garden, Cincinnati, OH 45220, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Stoops
authors.affiliation: Busch Gardens Tampa, SeaWorld Parks and Entertainment, Tampa, FL 33612, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Ball
authors.affiliation: SeaWorld and Busch Gardens Reproductive Research Center, SeaWorld Parks and Entertainment, 2595 Ingraham St, San Diego, CA 92109, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Steinman
authors.affiliation: SeaWorld and Busch Gardens Reproductive Research Center, SeaWorld Parks and Entertainment, 2595 Ingraham St, San Diego, CA 92109, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Montano
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
authors.forename: C C
authors.initials: CC
authors.lastname: Love
authors.affiliation: SeaWorld and Busch Gardens Reproductive Research Center, SeaWorld Parks and Entertainment, 2595 Ingraham St, San Diego, CA 92109, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Robeck
mesh_terms: D000818:Animals; D005260:Female; D014644:Genetic Variation; D008297:Male; D010527:Perissodactyla / Q000235:genetics* / Q000502:physiology*; D012662:Semen Preservation / Q000662:veterinary*; D012743:Sex Preselection / Q000662:veterinary*; D012744:Sex Ratio
keywords: CASA; DNA integrity; Directional freezing; Rhinoceros; SCSA; Sex-sorting