Laboratorio de Biotecnología de la Reproducción Animal, Facultad de Ciencias Agropecuarias, Universidad de Cuenca, EC010205, Cuenca, Ecuador.
Veterinary Reproduction Group, Department of Animal Medicine and Surgery, University of Cordoba, 14014, Cordoba, Spain.
Cryobiology. 2024 Jun;115:104884. doi: 10.1016/j.cryobiol.2024.104884. Epub 2024 Mar 7.
l-carnitine (LC) transports fatty acids to the mitochondria for energy production, reducing lipid availability for peroxidation through β-oxidation. This research examines the effect of LC supplementation to two skimmed milk-based extenders on the cryosurvival of chilled (5°C) and frozen-thawed Peruvian Paso horse spermatozoa .An initial experiment determined the optimal LC concentration (0, 1, 5, 10, 25, and 50 mM) when added to INRA-96® and UHT (skimmed milk + 6% egg yolk) extenders, using nine ejaculates from three stallions chilled for up to 96 h. Subsequently, the effect of 25 mM LC supplementation (the optimal concentration) on chilling (INRA-96) and freezing (INRA-Freeze®) extenders was evaluated using eight pooled samples from sixteen ejaculates (2 ejaculates/pool) from four stallions. Results indicated that all LC concentrations produced significantly higher values (P<0.05) for kinematic variables (total [TM] and progressive motilities, curvilinear [VCL] and straight-line [VSL] velocity, and beat-cross frequency [BCF]), and the integrity of plasma/acrosome membranes (IPIA) compared to non-supplemented chilled sperm samples for up to 96 h with both extenders. Moreover, the use of 25 mM LC was more efficient (P<0.05) in preserving the post-chilled values of velocity, BCF, and IPIA for the long term than lower LC concentrations (1-10 mM). Post-thaw values of total motility, the amplitude of lateral head displacement (ALH), and IPIA were significantly improved (P<0.05) when INRA-Freeze extender was supplemented with 25 mM LC. In conclusion, supplementation of l-carnitine to skimmed milk-based extenders enhanced kinematic variables and protected the membrane integrity in chilled and frozen-thawed Peruvian Paso horse spermatozoa.
左旋肉碱（LC）将脂肪酸转运到线粒体进行能量产生，通过β-氧化减少脂质的过氧化可用度。本研究探讨了 LC 补充剂对两种脱脂奶基稀释剂对冷却（5°C）和冷冻解冻秘鲁 Paso 马精子的冷冻保存效果。初始实验确定了添加到 INRA-96®和 UHT（脱脂奶+6%蛋黄）稀释剂中的最佳 LC 浓度（0、1、5、10、25 和 50 mM），使用来自三只种马的九个精液样本，在冷却至最多 96 h 时进行。随后，使用来自四只种马的十六个精液样本（2 个样本/池）的八个混合样本评估了 25 mM LC 补充（最佳浓度）对冷却（INRA-96）和冷冻（INRA-Freeze®）稀释剂的影响。结果表明，所有 LC 浓度都显著提高了运动学变量（总运动[TM]和前向运动、曲线速度[VCL]和直线速度[VSL]、鞭打频率[BCF]）和质膜/顶体膜完整性（IPIA）的数值（P<0.05），与未添加的冷却精子样本相比，在两种稀释剂中最多可达到 96 h。此外，与较低 LC 浓度（1-10 mM）相比，使用 25 mM LC 更有效地（P<0.05）保存长期冷却后速度、BCF 和 IPIA 的值。补充 25 mM LC 后，总运动、侧向头部位移（ALH）幅度和 IPIA 的解冻后值显著提高（P<0.05）。综上所述，在脱脂奶基稀释剂中添加左旋肉碱增强了运动学变量，并保护了冷却和冷冻解冻的秘鲁 Paso 马精子的膜完整性。
