冷冻稀释液中添加大豆卵磷脂对梅花鹿冻融精子质量的影响

【目的】 探究在冷冻稀释液中添加大豆卵磷脂代替10%卵黄对梅花鹿精液冷冻保存效果的影响,为梅花鹿人工授精体系的完善提供参考。【方法】 采用电刺激法采集梅花鹿精液,以精液冷冻稀释液中分别添加1%、2%、3%、4%和5%大豆卵磷脂代替10%卵黄作为试验组,添加20%卵黄作为对照组,分别进行各组精液冷冻保存。5 d后,进行精液解冻,检测解冻后各组精子的活力、质膜完整率、顶体完整率、线粒体活性、存活时间,筛选合适浓度的大豆卵磷脂。选取4~5岁健康雌性梅花鹿,肌肉注射300 IU孕马血清促性腺激素（PMSG）和0.4 mg氯前列醇钠进行同期发情处理,发情后第20 h用20%卵黄组与筛选出的大豆卵磷脂组冻精进行人工输精,输精后30 d使用B超检测仪检测妊娠情况,统计妊娠率。【结果】 与对照组相比,1%大豆卵磷脂组冻融后的精子活力、向前活动力、快速前进活力、活率、质膜完整率、顶体完整率及线粒体活性均显著提高（P<0.05）;随着稀释液中大豆卵磷脂浓度的增加,其冻融后精子活力、向前活动力、快速前进活力、活率、质膜完整率、顶体完整率以及线粒体活性呈下降趋势,精子存活时间也随浓度的增加而减少。1%大豆卵磷脂组冻融精子人工授精梅花鹿的妊娠率为61.11%,高于对照组、2%和3%大豆卵磷脂组,但差异均不显著（P>0.05）。【结论】 在梅花鹿精子冷冻稀释液中添加1%大豆卵磷脂替代10%卵黄,能有效提高梅花鹿冻融精子的质量,为进一步筛选新型梅花鹿精液冷冻稀释液提供理论基础。     

辅酶Q10对绒山羊精液冷冻保存效果的影响

旨在探讨辅酶Q10对绒山羊精液冷冻保存效果的影响。利用添加不同浓度辅酶Q10(4、40、400?滋g/mL)的精液冷冻稀释液对绒山羊精液样本进行冷冻保存,待冷冻精液解冻后,采用流式细胞仪和计算机辅助精液分析系统(CASAS)分别检测不同精液样本的精子活率、质膜完整率、顶体完整率、DNA完整率、线粒体膜电位和细胞内ROS水平。结果表明,当冷冻稀释液中添加浓度为40μg/mL辅酶Q10时,经历冷冻—解冻过程的绒山羊精液样本的精子活率、质膜完整率、顶体完整率均显著高于对照组(P<0.05);在冷冻稀释液中添加浓度为40μg/mL或400μg/mL的辅酶Q10均能显著提高线粒体膜电位并降低细胞内ROS水平(P<0.05)。综上所述,在冷冻稀释液中添加40μg/mL的辅酶Q10能够显著提高绒山羊精子抗氧化能力和冷冻保存效果。     

五种糖类对犬精液冷冻保存效果的研究

选取8只身体健康、性欲旺盛的比格公犬,采集其精液,对鲜精进行质量检测,主要包括颜色、射精量、精子活率、活力和pH。选取精子活率达到70%以上犬精液用于后续精液冷冻试验。分别将含有葡萄糖、果糖、蔗糖、乳糖和海藻糖的精液稀释液与精液按照1∶2的比例进行稀释。经冷冻解冻后,进行活率、活力、质膜完整性和顶体完整性的精子质量检测。通过对新鲜精液进行品质检测,结果显示5只合格用犬的平均射精量为2.85 mL,密度为2.01×10~8个/mL,pH为6.56。含有果糖的冷冻稀释液中精子活率和活力最高,分别达59.90%和54.00%;其次是添加葡萄糖和乳糖的稀释液中活率较高,分别为59.21%和56.73%,且两组稀释液中精子解冻后活力均为52.00%。进一步评估精子解冻后质膜完整率,结果显示葡萄糖和果糖组显著高于其他组,分别达48.73%和49.52%;而蔗糖添加组精子质膜完整率最低,为42.21%。稀释液中添加果糖的精子解冻后顶体完整率显著高于其他组,而添加蔗糖组顶体完整率最低。在比格犬的精液冷冻保存中,添加果糖的冷冻稀释液能显著提高精子的活率和活力,从而达到提高冻精质量的效果。     

添加低剂量大豆卵磷脂稀释液低温保存绵羊精液的优化研究

本实验旨在探讨添加低剂量大豆卵磷脂稀释液对绵羊精液低温保存效果。实验一采用6个浓度(0%、0.25%、0.5%、0.75%、1.0%、1.25%)大豆卵磷脂替代TRIS专利稀释液中卵黄低温保存绵羊精液,在第0、1、4、7、10、12、18天检测精子活率、顶体完整率;实验二选用实验一中最优添加组(0.5%组)和TRIS专利稀释液制成粉剂低温保存绵羊精液,在保存第0、1、4、7、10、12天对精子活率和顶体完整率进行测定,并在保存第10天对绵羊进行人工授精。结果表明:实验一中,0%组从第1天精子活率低于其他组(P<0.05),0.25%组精子活率观测值从第10天开始低于0.25%以上浓度组(P<0.05),0.5%、0.75%、1.0%、1.25%组保存第10天精子活率均大于50%,0.5%组保存第18天精子活率高于1.0%、1.25%组(P<0.05);各组顶体完整率缓慢下降,各时间点均无显著性差异;实验二中,0.5%组与TRIS组在各时间点的精子活率、顶体完整率与受胎率均无显著性差异,保存第10天精子活率均高于50%;0.5%组受胎率为65.49%,略低于TRIS组67.65%(P>0.05)。本实验条件下,绵羊精液低温保存稀释液中添加0.5%大豆卵磷脂替代卵黄效果最佳。     

新西兰兔精液冷冻保护剂的筛选

本试验的目的是分析在新西兰兔精液冷冻保存稀释液中分别添加不同浓度的海藻糖、透明质酸、维生素E(Ve)、超氧化物歧化酶(SOD)对兔精液冷冻保存效果的影响,以冻后精子活率、质膜完整性、顶体完整率等作为质量评定指标,筛选出效果较好的新西兰兔精液的冷冻保护剂种类及浓度。结果表明,精液冷冻保存稀释液中添加3种浓度的海藻糖均未提高兔精液冷冻后的精子活率、质膜完整率和顶体完整率(P0.05);添加0.5%和1%的透明质酸提高了兔精液冷冻后的精子活率(P0.05),但各组间质膜完整率和顶体完整率无显著差异;添加2 g/L Ve提高了兔精子4℃平衡后的活率、冷冻后精子活率、质膜完整率和顶体完整率(P0.05);添加4 000 IU的SOD提高了兔精子4℃平衡后的活率、冷冻后精子活率、质膜完整率和顶体完整率(P0.05)。结果证实,在新西兰兔精液冷冻保存稀释液中添加适宜浓度的Ve和SOD可提高兔精液冷冻后的精子活率、质膜完整率和顶体完整率。     

大豆卵磷脂与卵黄在山羊精液冷冻过程中的联合作用研究

试验旨在探究在山羊精液冷冻保存过程中单独使用大豆卵磷脂(SL)、卵黄(EY)及其联合使用的效果。以20%EY(V/V)和2%SL(m/V)为对照,在山羊冻精基础稀释液中分别添加10%EY+2%SL、20%EY+1%SL、20%EY+2%SL,冷冻解冻后分别对精子活率、精子活力、质膜完整率、顶体完整率和线粒体活性进行检测,同时利用试剂盒检测活性氧(ROS)、丙二醛(MDA)、超氧化物歧化酶(SOD)含量变化。结果表明:当冷冻稀释液中联合添加10%EY+2%SL,解冻后该组的精子活力、精子活率、质膜完整率、顶体完整率和线粒体活性与20%EY和2%SL对照组无显著性差异,较20%EY+1%SL和20%EY+2%SL联合添加组显著提高;与20%EY和2%SL组相比,联合添加10%EY+2%SL组精子解冻后ROS和MDA含量和SOD活性无显著性差异,但精子抗氧化能力较另外2个联合添加组显著提高。综上,山羊精液冷冻基础稀释液中添加SL可替代或者部分替代EY,EY和SL的联合添加对山羊冻精无协同作用,20%EY联合添加不同浓度的SL则会加大对冷冻精子的氧化损伤。     

新疆驴冷冻精液的研究

试验旨在探究新疆驴冷冻精液的最佳稀释保护液与处理方法。以假阴道采集新疆驴精液,并用5种不同稀释保护液稀释冷冻后,选取其中较为理想的稀释液作为对照组,再通过分别添加4%、5%、6%、8%甘油处理试验,最后再选用添加甘油后冷冻效果最优的稀释液为对照来进行离心浓缩试验。结果表明：①5号稀释液冷冻—解冻精液后,其活力、顶体完整率要显著高于其他4种稀释液（P<0.05）;②以5号稀释液为对照组,添加6%甘油(7号稀释液)冷冻后,精子的活力、顶体完整率要显著高于添加4%、5%、8%甘油组（P<0.05）;③以7号稀释液为对照组,通过离心浓缩,精液在冷冻后其活力和精子顶体完整率都显著提高（P<0.05）。结果提示,将驴精液用6%葡萄糖、2%乳糖、6%甘油为主的稀释液稀释,并经500 r/min离心浓缩10 min处理后,其冷冻效果最好。     

冷冻稀释液和抗氧化剂对金华猪精液冷冻效果的影响

为了探究不同冷冻稀释液及抗氧化剂对金华猪精液冷冻效果的影响,试验通过手握法采集健康的20月龄纯种金华猪公猪精液,采用两种常用的商品冷冻稀释液(A、B)稀释精液,然后液氮冻存1 d,解冻后测定精液精子活力、顶体完整率和质膜完整率指标,筛选最适金华猪精液冷冻保存的稀释液;在最适冷冻稀释液中添加20,30,40,50μmol/L表没食子儿茶素没食子酸酯(epigallocatechin gallate, EGCG),以未添加EGCG和上述添加EGCG的冷冻稀释液稀释金华猪精液,然后液氮冷冻保存精液1 d,解冻后测定精液精子活力、顶体完整率、质膜完整率及抗氧化指标[包括活性氧(reactive oxygen species, ROS)、丙二醛(malondialdehyde, MDA)含量及超氧化物歧化酶(superoxide dismutase, SOD)和过氧化氢酶(catalase, CAT)活性],筛选EGCG的最适添加量。结果表明：两种商品冷冻稀释液的精子活力、顶体完整率、质膜完整率差异不显著(P>0.05),但考虑到价格成本,选择B冷冻稀释液作为后续试验的冷冻稀释液。随着EG...     

附睾尾液对绵羊精液冷冻保存的影响

实验旨在研究冷冻稀释液中添加附睾尾液（Cauda Epididymal Fluid,CEF）对绵羊精液冷冻保存的影响。利用假阴道法收集4只湖羊精液并混合,以附睾尾液中总蛋白为基准,在冷冻稀释液中分别添加不同浓度CEF(0、140、280、420μg/mL)。精液经过冷冻后投入液氮保存,解冻后检测精子活力、运动参数,以及质膜完整率、顶体完整率、线粒体膜电位、37℃精子存活时间等指标。结果表明：冷冻-解冻后280μg/mL CEF组的精子活力、前向运动、平均路径速度、直线运动速度、直线度、线性度、头部横向位移幅度均显著高于其他各组（P<0.01）,曲线运动速度高于其他各组（P<0.05）;精子质膜完整率、顶体完整率也高于其他各组（P<0.05）;JC-1染色结果显示,280μg/mL CEF组精子线粒体膜电位高于其他各组（P<0.05）;280μg/mLCEF组精子在37℃环境下可存活14h,较对照组精子能多存活4h。可见,在冷冻稀释液中添加适量CEF可以提高精液的冷冻效果。     

褪黑素对绒山羊精液冷冻保存效果的影响

为了研究褪黑素对绒山羊精液冷冻保存效果的影响,在冷冻稀释液中外源补充不同浓度(0.125,0.250,0.500,1.000 mg/mL)的褪黑素进行冷冻试验,冷冻解冻采用计算机辅助精液分析系统(CASAS)和流式细胞仪分别检测精子活率、质膜完整率、顶体完整率以及精子细胞中活性氧(ROS)的含量。结果表明:在冷冻稀释液中添加褪黑素能够显著降低精子细胞中ROS的含量,而且在冷冻稀释液中添加浓度为0.500 mg/mL的试验组绒山羊精子活率(53.3%)、质膜完整率(44.6%)、顶体完整率(77.9%)均显著高于空白对照组(47.8%、36.3%和53.2%)(P0.05)。说明在绒山羊精液冷冻稀释液中添加0.500 mg/mL褪黑素能够显著提高绒山羊精子抗氧化能力和冷冻保存效果。     

Cryopreservation of Dog Semen in a Tris Extender with 1% or 2% Soya Bean Lecithin as a Replacement of Egg Yolk

Egg yolk is usually included in extenders used for preservation of dog semen. Lecithin is an interesting animal‐protein free alternative to egg yolk for semen preservation. The aim of our study was to evaluate soya bean lecithin for cryopreservation of dog semen. Five ejaculate replicates were divided in three equal parts, centrifuged and each pellet diluted with one of the three Tris‐based extenders containing 20% egg yolk, 1% soya bean lecithin or 2% soya bean lecithin. Extended semen was loaded in 0.5‐ml straws, cooled and diluted a second time and frozen in liquid nitrogen vapours. Sperm motility parameters (CASA), acrosome integrity (FITC‐PNA/PI) and sperm membrane integrity (C‐FDA) were evaluated 5 min post‐thaw and after 2 and 4 h of incubation. Total motility was significantly better in the egg yolk extender than in any of the lecithin‐based extender and was better in the 1% lecithin extender than in the 2% lecithin extender. Sperm membrane integrity was significantly better in the egg yolk extender than in any of the lecithin‐based extenders but did not differ significantly between the 1% and 2% lecithin extenders. Acrosome integrity was significantly better in the egg yolk extender than in the 2% lecithin extender but did not differ between the egg yolk extender and the 1% lecithin extender or between the two lecithin extenders. In conclusion, egg yolk was superior to lecithin in our study. The extender with 1% lecithin preserved sperm motility better than the extender with 2% lecithin.     

Optimization of Ram Semen Cryopreservation Using a Chemically Defined Soybean Lecithin‐Based Extender

The purpose of the present study was to investigate the effects of a chemically defined soybean lecithin‐based semen extender as a substitute for egg yolk‐based extenders in ram semen cryopreservation. In this study, 28 ejaculates were collected from four Zandi rams in the breeding season and then pooled together. The pooled semen was divided into six equal aliquots and diluted with six different extenders: (i) Tris‐based extender (TE) containing 0.5% (w/v) soybean lecithin (SL0.5), (ii) TE containing 1% (w/v) soybean lecithin (SL1), (iii) TE containing 1.5% (w/v) soybean lecithin (SL1.5), (iv) TE containing 2% (w/v) soybean lecithin (SL2), (v) TE containing 2.5% (w/v) soybean lecithin (SL2.5) and (vi) TE containing 20% (v/v) egg yolk (EYT). After thawing, sperm motility and motion parameters, plasma membrane and acrosome integrity, apoptosis status and mitochondrial activity were evaluated. The results shown that total and progressive motility (54.43 ± 1.33% and 25.43 ± 0.96%, respectively) were significantly higher in SL1.5 when compared to other semen extenders. Sperm motion parameters (VAP, VSL, VCL, ALH and STR) were significantly higher in SL1.5 compared to other extender, with the exception of SL1 extender. Plasma membrane integrity (48.86 ± 1.38%) was significantly higher in SL1.5 when compared to other semen extenders. Also, percentage of spermatozoa with intact acrosome in SL1.5 (85.35 ± 2.19%) extender was significantly higher than that in SL0.5, SL2.5 and EYT extenders. The results showed that the proportion of live post‐thawed sperm was significantly increased in SL1.5 extender compared to SL0.5, SL2 and EYT extenders. In addition, SL1, SL1.5 and SL2.5 extenders resulted in significantly lower percentage of early‐apoptotic sperm than that in EYT extender. There were no significant differences in different semen extenders for percentage of post‐thawed necrotic and late‐apoptotic spermatozoa. Also, the results indicated that there are slight differences for percentage of live spermatozoa with active mitochondria between extenders. In conclusion, SL1.5 extender was better than other extenders in most in vitro evaluated sperm parameters.     

大豆卵磷脂对马精液冷冻保存的效果研究

为探索适宜浓度的大豆卵磷脂(soybean lecithin,SL)代替卵黄(egg yolk,EY)对马精液冷冻保存的效果,本试验分别以5%卵黄(V/V)和10%、20%、30%大豆卵磷脂(m/V)作为精液的冷冻保护剂冷冻解冻马精液,解冻后分别对精子细胞的运动参数、精子细胞膜的完整性、精子细胞脂质氧化物丙二醛的值和线粒体膜完整性进行检测。结果发现,精液冷冻解冻后,5%卵黄和10%、20%、30%大豆卵磷脂对精子的总运动精子数无显著影响(P>0.05),但30%大豆卵磷脂具有最大的原地摆动精子数和最小的直线前进精子数(P<0.05),其他运动参数差异不显著(P>0.05);20%大豆卵磷脂代替卵黄后具有最高的质膜完整性,同时产生最少的脂质氧化物丙二醛;线粒体膜电位经流式细胞仪检测时,30%大豆卵磷脂活精子高膜电位数最高,但与20%大豆卵磷脂之间差异不显著(P>0.05)。试验结果表明,20%大豆卵磷脂能够代替卵黄作为冷冻保护剂用于马精液的冷冻保存。     

Comparison of in vitro and in vivo fertilizing potential of buffalo bull semen frozen in egg yolk‐, soya bean lecithin‐ and liposome‐based extenders

The objective of this study was to compare different extenders for post‐thaw in vitro sperm function and in vivo fertility of buffalo semen. Accordingly, sperm of 30 ejaculates extended in egg yolk (TRIS with 20% egg yolk; EY), two soya lecithin‐based (SL‐1; AndroMed^® and SL‐2; Bioxcell^®) and a liposome‐based extender (LS; OptiXcell^®) were tested. The post‐thaw semen was evaluated for computer‐assisted sperm analysis (CASA), sperm viability, membrane and acrosome integrity, DNA integrity and acrosome reaction and first service pregnancy rate (FSPR) in a fixed‐time artificial insemination programme. Total motility and VCL were the only CASA‐based parameters that exhibited significantly higher (p < .05) percentage in LS among these extenders. Post‐thaw percentage of acrosome integrity (55.9 ± 1.4, 58.1 ± 2.0, 55.8 ± 2.0, 56.6 ± 2.3) and DNA integrity (68.8 ± 2.0, 69.2 ± 2.3, 71.3 ± 2.1, 69.1 ± 2.1) did not differ (p > .05) in EY, SL‐1, SL‐2 and LS extender, respectively. However, a variable response in terms of efficacy of different extenders for sperm viability and plasma membrane integrity was observed. Assessment of inducibility of acrosome reaction showed significant differences between extenders (51.9 ± 2.1, 44.3 ± 2.4, 46.1 ± 2.3 and 58.1 ± 3.1%, respectively, for EY, SL‐1, SL‐2 and LS). Furthermore, field trials revealed significantly higher (p < .05) FSPR of LS‐extended semen as compared to that for EY, SL‐1 and SL‐2 extender (46.3%, 41.2%, 31.2% and 29.7%, respectively). It is concluded that the liposome‐based extender is more effective than egg yolk‐ and soya lecithin‐based extenders and may be used for cryopreservation of buffalo semen in the future.     

Studies on the Effect of Supplementing Boar Semen Cryopreservation Media with Different Avian Egg Yolk Types on in Vitro Post-thaw Sperm Quality

Fertility after insemination of cryopreserved boar semen is currently below that of fresh semen. In an attempt to improve the post-thaw motility and acrosome integrity of boar sperm, semen was frozen using an adapted Westendorf method in which the chicken egg yolk was replaced by either duck or quail egg yolk. The different composition of the yolk types, particularly the amount of cholesterol, fatty acids and phospholipids, were thought to potentially afford a greater level of protection to sperm against damage during freezing and thawing. Sperm frozen in medium containing chicken egg yolk displayed higher motility immediately after thawing, but there was no difference in the motility of sperm frozen with different types of egg yolk 3 or 6 h after thawing and maintenance at 37 degrees C. Sperm frozen in media containing chicken or duck egg yolk had a higher proportion of intact acrosomes immediately after thawing than sperm frozen in medium containing quail egg yolk, but 6 h after thawing and maintenance at 37 degrees C the sperm that had been frozen in medium containing chicken egg yolk had a higher proportion of intact acrosomes than the sperm frozen in media containing duck or quail egg yolk. Analysis of the composition of the different yolk types showed that the basic components of the yolks were similar, but the ratios of fatty acids and phospholipid classes differed. Duck egg yolk had more monounsaturated fatty acids (MUFA) than chicken egg yolk, which had more MUFA than quail egg yolk. Duck egg yolk contained more phosphotidylinositol (PI) than chicken or quail egg yolks and quail egg yolk contained more phosphotidylserine than either chicken or duck egg yolks. The differences in post-thaw motility and acrosome integrity of boar sperm when frozen in media containing the different types of egg yolk may be due to the variation in composition.     

AMPK激活剂在绵羊精液冷冻保存中的作用研究

旨在研究AMPK激活剂二甲双胍（metformin，Met）和阿卡地新（acadesine，AICAR）对绵羊精液冷冻保存效果的影响。本研究首先在冷冻基础稀释液中分别添加不同浓度（0、100、200、300、400、500 μmol·L^-1）的Met和AICAR，冷冻解冻后根据精子活力、运动性能和结构完整性指标筛选出最佳的添加浓度（400 μmol·L^-1 Met、200 μmol·L^-1 AICAR）；然后分别使用不同的冷冻稀释液（对照组：稀释液；Met组：含400 μmol·L^-1 Met的稀释液；AICAR组：含200 μmol·L^-1 AICAR的稀释液）冷冻精液，解冻后检测精子中AMPK蛋白表达、顶体酶活性、代谢指标、线粒体功能以及抗氧化酶活性。结果表明，稀释液中添加400 μmol·L^-1 Met和200 μmol·L^-1AICAR均可显著提高解冻后精子活力、运动性能及精子结构完整性（P<0.05），其中400 μmol·L^-1 Met组精子总活力达43.20%，顶体完整率为91%，质膜完整率为46%。与对照组相比，Met组和AICAR组解冻后精子中AMPK磷酸化水平显著升高（P<0.05）；顶体酶活性显著提高（P<0.05）；丙酮酸水平显著下降（P<0.05），乳酸脱氢酶活性、乳酸以及ATP含量均显著升高（P<0.05）；与对照组相比，Met和AICAR组稀释液更有利于维持线粒体膜电位（P<0.05），提高ATP酶（P<0.05）以及抗氧化酶的活性（P<0.05）。添加适当浓度的AMPK激活剂可以提高绵羊精液冷冻保存的效果。     

Study on the Role of AMPK Activator in Cryopreservation of Sheep Semen

This study aimed to investigate the effects of AMPK activators metformin (Met) and acadesine (AICAR) on sheep semen cryopreservation. Firstly, Met and AICAR with different concentrations (0, 100, 200, 300, 400, 500 μmol·L^-1) were added into the frozen diluent. After freezing and thawing, the optimal concentration (400 μmol·L^-1 Met, 200 μmol·L^-1 AICAR) were selected based on sperm motility, motion performance and membrane integrity; Secondly, the collected semen was froze using different frozen diluents (control group:diluent; Met group:diluent + 400 μmol·L^-1 Met; AICAR group:diluent + 200 μmol·L^-1 AICAR). After thawing, the sperm AMPK protein expression, acrosomal enzyme activity, metabolic index, mitochondrial function and antioxidant enzyme activity were examined. The results showed that the addition of 400 μmol·L^-1 Met and 200 μmol·L^-1 AICAR could significantly improve sperm motility, motion performance and membrane integrity(P<0.05) after thawing. In 400 μmol·L^-1 Met group, the total sperm motility, acrosome integrity rate and plasma membrane integrity rate were 43.20%, 91% and 46%, respectively. Compared with the control group, the level of AMPK phosphorylation in the sperm of the Met and AICAR groups was significantly increased after thawing (P<0.05), the acrosome enzyme activity of sperm was significantly increased(P<0.05); the pyruvate level was significantly decreased (P<0.05), the lactate dehydrogenase activity, lactic acid content, and ATP content were significantly increased(P<0.05). Compared with the control group, the dilution of Met group and AICAR group was more conducive to maintain mitochondrial membrane potential (P<0.05), increase ATPase and antioxidant enzyme activity (P<0.05). The addition of appropriate concentrations of Met and AICAR could improve semen quality of cryopreservation in sheep.     

Comparison of Different Glycerol and Egg Yolk Concentrations Added to Tris‐based Extender for the Collared Peccaries (Tayassu tajacu) Semen Freezing

This study aimed to evaluate various concentrations of egg yolk (5, 10, or 20%) in combination with different concentrations of glycerol (3% or 6%) added to a Tris‐based extender on the post‐thaw characteristics of sperm obtained from Tayassu tajacu. For this purpose, semen from 10 sexually male mature collared peccaries was collected by electroejaculation and evaluated for sperm motility, vigour, viability, morphology and functional membrane integrity. The ejaculates were initially extended in Tris‐fructose plus egg yolk (5%, 10% or 20%). After cooling, the semen was added to Tris‐egg yolk plus glycerol (6% or 12%), resulting in a final concentration of 3% or 6% glycerol of the extender. Straws were frozen using liquid nitrogen and thawed in a water bath at 37°C for 30 s. The frozen–thawed semen was evaluated as reported for fresh semen. After thawing, a significant decrease was verified for sperm motility and vigour, for all the samples in comparison with fresh semen. However, no differences were evidenced among treatments for any sperm characteristics evaluated (p > 0.05), except for the combination between 10% egg yolk and 6% glycerol, which provided the worst preservation of functional membrane integrity (p < 0.05). The interactions between higher concentrations of egg yolk (20%) and glycerol (6%) and also between lower concentrations of the same substances (5% egg yolk and 3% glycerol) added to the Tris‐based extender negatively affected the preservation of the normal sperm morphology after thawing (p < 0.05). In conclusion, the use of Tris‐based extender added to 10% or 20% egg yolk plus 3% glycerol is recommended for effective sperm cryopreservation in collared peccaries.