Liposome‑based extender consistently improves post-thaw semen quality in rams
Abstract
Cryopreservation of ram spermatozoa is essential for genetic improvement and germplasm conservation but remains limited by cryo-induced post-thaw deterioration. Conventional egg-yolkbased (EY) extenders suffer from biological variability and biosecurity concerns, motivating the development of chemically defined alternatives. This in vitro study compared a commercial liposome-based extender (LB; OptiXcell®, IMV Technologies) with an EY extender for ram semen cryopreservation using a split-ejaculate design across two independent experiments (42 ejaculates; contrasting management and seasonal conditions). Post-thaw quality was assessed by computer-assisted sperm analysis (CASA; total and progressive motility, VAP, VCL, VSL), flow cytometry (plasma membrane integrity, acrosome integrity, mitochondrial membrane potential), and the hypo-osmotic swelling test (HOST). LB-cryopreserved semen showed higher post-thaw total motility (Experiment I: 34.8 ± 4.2% vs 25.1 ± 3.5%; Experiment II: 40.8 ± 4.1% vs 34.3 ± 4.1%) and progressive motility, with velocity parameters significantly improved. A greater proportion of spermatozoa with intact plasma membranes (Experiment I: 41.9 vs 27.4%; Experiment II: 51.5 vs 37.0%) and preserved acrosomes was detected in LB-treated samples. Mitochondrial membrane potential was higher with LB in Experiment II only (73.5 ± 4.2% vs 59.3 ± 4.2%), reflecting the context-dependent sensitivity of this endpoint. No difference was detected by HOST. Despite inter-individual variability, 94% of ejaculates exhibited higher plasma membrane integrity and two-thirds showed higher total motility with LB. These findings indicate that chemically defined liposome-based extenders improve multiple in vitro indicators of ram sperm function, whilst in vivo fertility trials remain necessary to confirm reproductive relevance.
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BibTeX
@article{mazenod2026liposomebased,
title = {{Liposome‑based extender consistently improves post-thaw semen quality in rams}},
author = {Elodie Mazenod and Loris Commin and Florine Bontemps and Lionel Boyer and Samuel Buff and Elodie Pillet-Michelland},
journal = {Animal Reproduction Science},
year = {2026},
month = may,
doi = {10.1016/j.anireprosci.2026.108238},
url = {https://hal.science/hal-05797603v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Liposome‑based extender consistently improves post-thaw semen quality in rams
AU - Elodie Mazenod
AU - Loris Commin
AU - Florine Bontemps
AU - Lionel Boyer
AU - Samuel Buff
AU - Elodie Pillet-Michelland
PY - 2026
DA - 2026/05/14
JO - Animal Reproduction Science
DO - 10.1016/j.anireprosci.2026.108238
UR - https://hal.science/hal-05797603v1
AB - Cryopreservation of ram spermatozoa is essential for genetic improvement and germplasm conservation but remains limited by cryo-induced post-thaw deterioration. Conventional egg-yolkbased (EY) extenders suffer from biological variability and biosecurity concerns, motivating the development of chemically defined alternatives. This in vitro study compared a commercial liposome-based extender (LB; OptiXcell®, IMV Technologies) with an EY extender for ram semen cryopreservation using a split-ejaculate design across two independent experiments (42 ejaculates; contrasting management and seasonal conditions). Post-thaw quality was assessed by computer-assisted sperm analysis (CASA; total and progressive motility, VAP, VCL, VSL), flow cytometry (plasma membrane integrity, acrosome integrity, mitochondrial membrane potential), and the hypo-osmotic swelling test (HOST). LB-cryopreserved semen showed higher post-thaw total motility (Experiment I: 34.8 ± 4.2% vs 25.1 ± 3.5%; Experiment II: 40.8 ± 4.1% vs 34.3 ± 4.1%) and progressive motility, with velocity parameters significantly improved. A greater proportion of spermatozoa with intact plasma membranes (Experiment I: 41.9 vs 27.4%; Experiment II: 51.5 vs 37.0%) and preserved acrosomes was detected in LB-treated samples. Mitochondrial membrane potential was higher with LB in Experiment II only (73.5 ± 4.2% vs 59.3 ± 4.2%), reflecting the context-dependent sensitivity of this endpoint. No difference was detected by HOST. Despite inter-individual variability, 94% of ejaculates exhibited higher plasma membrane integrity and two-thirds showed higher total motility with LB. These findings indicate that chemically defined liposome-based extenders improve multiple in vitro indicators of ram sperm function, whilst in vivo fertility trials remain necessary to confirm reproductive relevance.
SN - 0378-4320
SN - 1873-2232
ER -