Fertilization Potential of Cold-Stored Fowler's Toad (Anaxyrus fowleri) Spermatozoa: Temporal Changes in Sperm Motility Based on Temperature and Osmolality

ORCID

Arregui: https://orcid.org/0000-0002-4355-0155; CKouba: https://orcid.org/0000-0001-8466-6077

MSU Affiliation

College of Agriculture and Life Sciences; Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology; College of Forest Resources; Department of Wildlife, Fisheries and Aquaculture

Creation Date

2026-10-30

Abstract

Asynchrony of gamete release is problematic in amphibian captive breeding programs but can be overcome by short-term storage of spermatozoa. Hormonally induced sperm from the model species Anaxyrus fowleri were used to determine storage conditions for optimal fertilisation capacity. Sperm motility was measured over time, as a function of storage temperature (4°C or 22°C) and solution osmolality (7–40 mOsm/kg). Sperm at 40 mOsm/kg (spermic urine) stored at 4°C exhibited higher motility compared to 22°C. Also, sperm stored at 40 mOsm/kg retained higher motility compared to sperm stored below 15 mOsm/kg at both temperatures. Under optimal storage conditions (40 mOsm and 4°C) a 30% decrease in sperm motility occurred within 24 h, however, subsequent loss of sperm motility was lower (< 10%/day) for days 2–8 thereafter. Sperm samples stored for 1–8 days under optimal conditions were tested for fertilising capacity by conducting in vitro fertilisation trials. Sperm stored for 8 days yielded 48% neurula development, similar to sperm stored for 1 day, which produced 60% neurula development. Overall, sperm stored for up to 8 days at 4°C as spermic urine retained fertilising capacity and thus can be used to circumvent asynchronous gamete release in assisted breeding efforts for amphibians.

Keywords

amphibian, anuran, bufonid, captive breeding, embryo, human chorionic gonadotrophin, in vitro fertilisation, reproduction

Publication Date

11-1-2021

Publication Title

Reproduction, Fertility and Development

Publisher

CSIRO Publishing

First Page

461

Last Page

469

Rights

© 2022 The Author(s) (or their employer(s))

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Digital Object Identifier (DOI)

https://doi.org/10.1071/RD21037