Effect of reduced osmolality in glucose-based extenders on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa

The current study aimed to compare the effects of decreasing osmolality in glucose-based 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 Bi...

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Main Authors: Aleksandra Krasilnikova, Michele Di Iorio, Emanuele Antenucci, Stefano Esposito, Nicolaia Iaffaldano, Martin Pšenička
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-07-01
Series:Frontiers in Marine Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2025.1621496/full
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author Aleksandra Krasilnikova
Michele Di Iorio
Emanuele Antenucci
Stefano Esposito
Nicolaia Iaffaldano
Martin Pšenička
author_facet Aleksandra Krasilnikova
Michele Di Iorio
Emanuele Antenucci
Stefano Esposito
Nicolaia Iaffaldano
Martin Pšenička
author_sort Aleksandra Krasilnikova
collection DOAJ
description The current study aimed to compare the effects of decreasing osmolality in glucose-based 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 × 109 spermatozoa/mL, corresponding to 750 × 106 spermatozoa/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.
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spelling doaj-art-04046bce51334f00a985303b30d320152025-08-20T03:18:01ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452025-07-011210.3389/fmars.2025.16214961621496Effect of reduced osmolality in glucose-based extenders on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoaAleksandra Krasilnikova0Michele Di Iorio1Emanuele Antenucci2Stefano Esposito3Nicolaia Iaffaldano4Martin Pšenička5Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, University of South Bohemia in České Budějovice, Vodňany, CzechiaDepartment of Agricultural, Environmental and Food Sciences, University of Molise, Campobasso, ItalyDepartment of Agricultural, Environmental and Food Sciences, University of Molise, Campobasso, ItalyDepartment of Agricultural, Environmental and Food Sciences, University of Molise, Campobasso, ItalyDepartment of Agricultural, Environmental and Food Sciences, University of Molise, Campobasso, ItalyFaculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, University of South Bohemia in České Budějovice, Vodňany, CzechiaThe current study aimed to compare the effects of decreasing osmolality in glucose-based 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 × 109 spermatozoa/mL, corresponding to 750 × 106 spermatozoa/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.https://www.frontiersin.org/articles/10.3389/fmars.2025.1621496/fullcryopreservationspermcryomediumMediterranean brown troutmotility
spellingShingle Aleksandra Krasilnikova
Michele Di Iorio
Emanuele Antenucci
Stefano Esposito
Nicolaia Iaffaldano
Martin Pšenička
Effect of reduced osmolality in glucose-based extenders on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa
Frontiers in Marine Science
cryopreservation
sperm
cryomedium
Mediterranean brown trout
motility
title Effect of reduced osmolality in glucose-based extenders on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa
title_full Effect of reduced osmolality in glucose-based extenders on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa
title_fullStr Effect of reduced osmolality in glucose-based extenders on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa
title_full_unstemmed Effect of reduced osmolality in glucose-based extenders on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa
title_short Effect of reduced osmolality in glucose-based extenders on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa
title_sort effect of reduced osmolality in glucose based extenders on the post thaw motility of mediterranean brown trout salmo cettii spermatozoa
topic cryopreservation
sperm
cryomedium
Mediterranean brown trout
motility
url https://www.frontiersin.org/articles/10.3389/fmars.2025.1621496/full
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