Short-term storage of tiger salamander (Ambystoma tigrinum) spermatozoa: The effect of collection type, temperature and time

Amanda B Gillis; Emmet L Guy; Andrew J Kouba; Peter J Allen; Ruth M Marcec-Greaves; Carrie K Kouba

doi:10.1371/journal.pone.0245047

Short-term storage of tiger salamander (Ambystoma tigrinum) spermatozoa: The effect of collection type, temperature and time

PLoS One. 2021 Jan 11;16(1):e0245047. doi: 10.1371/journal.pone.0245047. eCollection 2021.

Authors

Amanda B Gillis¹, Emmet L Guy¹, Andrew J Kouba², Peter J Allen², Ruth M Marcec-Greaves³, Carrie K Kouba¹

Affiliations

¹ Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS, United States of America.
² Department of Wildlife, Fisheries, and Aquaculture, Mississippi State University, Mississippi State, MS, United States of America.
³ National Amphibian Conservation Center, Detroit Zoological Society, Royal Oak, MI, United States of America.

Abstract

The aims of this project were to characterize tiger salamander (Ambystoma tigrinum) spermatozoa motility over time, when excreted as either milt or spermic urine prior to packaging into a spermatophore, and to determine the effect of temperature on sperm motility. A split-plot design was utilized to assess the motility of the two pre-spermatophore sample types at two temperatures, 0°C and 20°C (n = 10 for each treatment). Spermiation was induced through exogenous hormone treatment of luteinizing hormone releasing hormone analog in order to collect both milt and spermic urine, which were evaluated for motility, divided into two separate aliquots, and subsequently stored in either an ice-bath (0°C) or on the benchtop (20°C). The decay rate of sperm motility was assessed by reevaluating subsamples at 0.5, 1, 2, 3, 5, 7, and 24 hours following the initial assessment. Results showed that sperm stored at 0°C had significantly higher progressive, non-progressive, and total motility for both sperm collection types over time. An interaction was found between collection type and time, with milt exhibiting lower initial motility that was more sustainable over time, compared to spermic urine. For both milt and spermic urine, motility decreased rapidly with storage duration, indicating samples should be used as soon as possible to maximize motility for in-vitro fertilization and cryopreservation. This is the first study to describe the differences in sperm motility between milt and spermic urine from an internally fertilizing caudate and demonstrates the benefits of near freezing temperatures on sperm longevity.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Ambystoma*
Animals
Cryopreservation / methods*
Male
Semen Preservation / methods*
Specimen Handling
Sperm Motility / physiology*
Spermatozoa*
Temperature
Time Factors

Grants and funding

This work was sponsored by the Institute of Museum and Library Services (IMLS) National Leadership Grant (# MG-30-17-0052-17; imls.gov; CKV, AJK, RMMG) and is a contribution of the Mississippi Agricultural and Forestry Experiment Station (mafes.msstate.edu) and the material is based upon work supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch project under the accession number W3173 (nifa.usda.gov). In addition, the study was partially supported by the USDA-ARS Biophotonics Initiative grant #G00003581.(ars.usda.gov; CKV). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.