BRIEF RESEARCH REPORT article
Front. Mar. Sci.
Sec. Marine Biotechnology and Bioproducts
Volume 12 - 2025 | doi: 10.3389/fmars.2025.1621496
This article is part of the Research TopicGenomic Cell Preservation in Aquatic Animals: With Emphasis on CryopreservationView all 5 articles
Effect of reduced osmolality in glucose-based extenders on the postthaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa
Provisionally accepted
Aleksandra Krasilnikova1*
Michele Di Iorio1
Emanuele Antenucci2
Stefano Esposito2
Nicolaia Iaffaldano2
Martin Psenicka1- 1Faculty of Fishery and Protection of Waters, University of South Bohemia, Vodňany, Czechia
- 2Department of Agricultural, Environmental and Food Sciences, University of Molise, Campobasso, Italy
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The current study aimed to compare the effects of decreasing osmolality in extenders containing methanol alone versus a methanol-ethylene glycol combination on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa. Milt was collected from mature males in the Biferno River, Southern Italy, and cryopreserved using a control cryomedium (150 mM glucose with 7.5% methanol) and experimental variants with reduced glucose (100 mM, 50 mM) paired with methanol alone or combined with 2.5% ethylene glycol. Samples were cryopreserved in 0.25 mL straws with a final sperm concentration of 3.0 × 10 9 sperm/mL, corresponding to 750 × 10 6 sperm/straw. Sperm motility and kinematic parameters of Mediterranean brown trout were assessed for fresh sperm and post-thaw samples cryopreserved in various cryomedia. Fresh sperm exhibited robust motility (89.0 ± 8.4%) and curvilinear velocity (VCL, 121.2 ± 22.4 µm/s), while the control cryomedium preserved motility at 65.9 ± 12.9% and VCL at 117.6 ± 26.1 µm/s; the experimental 100 mM glucose with 7.5% methanol and 2.5% ethylene glycol treatment yielded comparable motility (65.6 ± 11.6%) but reduced VCL (81.5 ± 16.1 µm/s, p < 0.05). Other treatments showed diminished efficacy, particularly at 50 mM glucose. These findings reveal that a hypotonic extender with methanol-ethylene glycol synergy sustains motility after cryopreservation despite lower glucose levels, demonstrating that the osmotic threshold of extender can be lowered to 100 mOsm/kg without compromising salmonid sperm function. This approach offers a practical tool for conserving S. cettii, supporting broader restoration efforts amid escalating environmental pressures.
Keywords: Cryopreservation, sperm, Cryomedium, Mediterranean brown trout, motility
Received: 01 May 2025; Accepted: 23 Jun 2025.
Copyright: © 2025 Krasilnikova, Di Iorio, Antenucci, Esposito, Iaffaldano and Psenicka. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Aleksandra Krasilnikova, Faculty of Fishery and Protection of Waters, University of South Bohemia, Vodňany, Czechia
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