棘头梅童鱼精子超低温冷冻保存研究

为保护和利用棘头梅童鱼种质资源,以常用无机盐及葡萄糖配制的5种溶液(依次编号A、B、C、D、E)作为稀释液,不同体积分数的DMSO作为抗冻剂,采用2 mL冻存管和两步降温的方式,对棘头梅童鱼精子的超低温冷冻保存技术进行了研究,并利用人工养殖黄姑鱼的成熟卵子对冻存3年的棘头梅童鱼冷冻精子的授精能力进行检验。结果表明,以E溶液为稀释液、10%DMSO为抗冻剂、两步降温方式冷冻保存的棘头梅童鱼精子在37℃水浴解冻后复活率较高,为(76.67±10.41)%^82.33±4.62%;以上述方法冻存3年的棘头梅童鱼冷冻精子与人工养殖黄姑鱼的成熟卵子杂交,受精率达到(20.26±4.12)%。     

人工养殖西伯利亚鲟精子超低温冷冻保存研究

研究了人工养殖西伯利亚鲟精子的生物学特征及超低温冷冻保存方法。西伯利亚鲟的产精量为113.67±39.86 ml,精子密度为(6.49±3.10)×108/ml,精子活力为(85.4±9.5)%,精子寿命为353±23 s。精子密度与精子快速运动时间、精子寿命之间均存在线性相关,用方程分别表示为:y=1.0384x+1.5089(R2=0.7325);y=2.9069x+74.289(R2=0.6967)。结果表明精子密度可作为一项精子质量评价的标准。通过比较西伯利亚鲟精子在不同稀释液、不同抗冻剂和抗冻剂浓度、降温速率、解冻温度下的保存效果,结果表明:配方2作为稀释液,18%甲醇作为抗冻剂,二步法超低温(-196℃)冷冻保存精子,40℃水浴解冻取得最好的冻后活力,解冻后活力为(51.8±5.8)%。西伯利亚鲟授精的最佳精卵比为106∶1。在此精卵比下用冻精授精分别得到了(72.3±3)%的受精率和(52.9±4.1)%的孵化率,其中受精率与鲜精没有显著性差异,孵化率与鲜精有显著差异(P<0.05)。     

鱼类精子超低温冷冻保存技术及其应用

鱼类精子的超低温冷冻保存对鱼类种质资源保护、低温生物学、遗传育种和水产养殖业都具有重要的意义。鱼类精子超低温冷冻保存技术主要包括冷冻保存方法、抗冻保护液、降温、解冻速率、冷冻保存温度、抗冻剂去除等过程。本文就鱼类精子超低温冷冻保存技术及其应用进行了综述。     

条纹锯鮨精液超低温冷冻保存研究

为建立条纹锯鮨精液超低温冷冻保存方法,实验采用计算机辅助精子分析系统(CASA)分析了采用6种抗冻保护剂(GLY[甘油]、DMSO[二甲基亚砜]、PG[丙二醇]、EG[乙二醇]、METH[甲醇]、DMA[二甲基乙酰胺])在4种浓度(5%、10%、15%、20%,v/v)下对条纹锯鮨精液的冷冻保存效果。结果发现,以HBSS为稀释液,采用程序降温仪分步降温冷冻保存条纹锯鮨精液,37℃水浴解冻后的精子中,15%PG作为抗冻保护剂的精子运动率最高,达到(93.1±0.9)%,与鲜精差异不显著(P0.05),15%PG作为抗冻保护剂的精子水浴解冻后精子的运动速度最高,平均直线速度、平均曲线速度、平均路径速度分别达到了(88.3±0.3)μm/s、(76.2±0.5)μm/s、(86.7±0.7)μm/s,与鲜精差异不显著(P0.05)。在不同种类及不同浓度抗冻保护剂保护下,15%PG作为抗冻保护剂的精子解冻后1 min内运动率变化与鲜精差异不显著(P0.05)。研究表明,15%PG为条纹锯鮨最佳抗冻保护剂,可用于条纹锯鮨精液的超低温冷冻保存。     

不同稀释液对香港牡蛎精子冷冻保存效果的研究

分别以生理盐水、柠檬酸钠-甘氨酸液、海水、KCl-NaCl溶液、Hank’s液、D-Hank’s液为稀释液,不同浓度二甲基亚砜(dimethylsulfoxide,DMSO)及海藻糖为抗冻剂,研究超低温冷冻保存香港牡蛎(Crassostrea hongkongensis)精子方法及不同浓度含氨海水对复苏精子的激活效果,以筛选出最适宜精子冷冻保存的稀释液和抗冻剂及其浓度。结果显示,柠檬酸钠-甘氨酸液为稀释液复苏后精子成活率最高,为(82.90%±0.19%);其次是生理盐水(77.57%±0.49%)、D-Hank’s液(72.22%±0.36%)、Hank’s液(70.00%±0.28%)。氨海水终浓度为0.0313%时,复苏后精子活力最强,柠檬酸钠-甘氨酸溶液为稀释液精子活力为(61.25%±3.06%),生理盐水为稀释液精子活力为(68.70%±0.74%)。以生理盐水为稀释液、DMSO浓度为14%冷冻保存时,复苏精子存活率最高,含海藻糖精子存活率为(86.91%±3.14%),不含海藻糖精子存活率为(81.81%±3.68%),以柠檬酸钠-甘氨酸液为稀释液、DMSO浓度为12%时,复苏后精子存活率最高,含海藻糖的为(79.62%±1.95%),不含海藻糖的为(70.58%±2.41%)。     

云纹石斑鱼精子冷冻保存

以云纹石斑鱼精液为实验材料,对精子稀释液、抗冻剂种类和适宜浓度、冷冻保存液进行了筛选。结果表明,利用9g/L NaCl、10g/L KHCO3和10%小牛血清配制而成的稀释液EM1-2适宜于云纹石斑鱼精子冷冻保存,以2ml冷冻管为精子容器,在60L液氮生物保存罐中冷冻保存精子,冷冻解冻精子活力可达56.67%±5.77%,要优于TS-2、ES1-3和其他EM系列稀释液冷冻保存精子活力。利用EM1-2为基础液对抗冻保护剂进行筛选,结果显示,10%~20%的二甲基亚砜(DMSO)和1-2-丙二醇(PG)冷冻保存后精子活力无显著差异(P0.05),其中15%的DMSO和10%PG冷冻保存精子效果最优,解冻后精子活力分别可达54.52%±7.81%和57.24%±3.69%。利用冷冻保存1年的精液与云纹石斑鱼卵进行受精,受精率和孵化率均达到80%以上,与新鲜精子无显著性差异(P0.05)。本研究表明,利用EM1-2配制15%的DMSO或10%的PG可用于冷冻保存云纹石斑鱼精液。在此基础上,建立了精子冷冻库,保存精子130ml,为人工繁育和杂交育种提供了丰富的精子源。     

云纹石斑鱼精子冷冻保存

以云纹石斑鱼精液为实验材料,对精子稀释液、抗冻剂种类和适宜浓度、冷冻保存液进行了筛选。结果表明,利用9g/L NaCl、10g/L KHCO3和10%小牛血清配制而成的稀释液EM1-2适宜于云纹石斑鱼精子冷冻保存,以2ml冷冻管为精子容器,在60L液氮生物保存罐中冷冻保存精子,冷冻解冻精子活力可达56.67%±5.77%,要优于TS-2、ES1-3和其他EM系列稀释液冷冻保存精子活力。利用EM1-2为基础液对抗冻保护剂进行筛选,结果显示,10%~20%的二甲基亚砜(DMSO)和1-2-丙二醇(PG)冷冻保存后精子活力无显著差异(P0.05),其中15%的DMSO和10%PG冷冻保存精子效果最优,解冻后精子活力分别可达54.52%±7.81%和57.24%±3.69%。利用冷冻保存1年的精液与云纹石斑鱼卵进行受精,受精率和孵化率均达到80%以上,与新鲜精子无显著性差异(P0.05)。本研究表明,利用EM1-2配制15%的DMSO或10%的PG可用于冷冻保存云纹石斑鱼精液。在此基础上,建立了精子冷冻库,保存精子130ml,为人工繁育和杂交育种提供了丰富的精子源。     

瓦氏黄颡鱼精子的生理特性及其超低温冷冻保存的初步研究

对瓦氏黄颡鱼(Pelteobagrus vachelli)精子在不同盐度和pH下的精子活力进行观察,同时研究了精子在4种不同稀释液与2种不同浓度抗冻剂组成的保存液中的超低温冷冻保存,并开展了冻精的授精实验。结果表明,瓦氏黄颡鱼精子浓度为(2.035±0.179)×1012cell·mL-1,在盐度为5.8、pH为7.17时,精子的活力都高达95%。以A液作为稀释液、10%甲醇作为抗冻剂时,冷冻保存精子效果最好,解冻后精子活力为(81.7±0.9)%。用解冻后的精子进行人工授精,获得的受精率为(88.4±2.1)%,孵化率为(74.0±0.8)%;而鲜精受精率为(91.0±0.8)%,孵化率(82±1.6)%,冻精与鲜精均无显著性差异。人工授精实验证明了解冻后的精子能正常用于该鱼的人工繁殖。     

祁连山裸鲤精液保存的研究

<正>本实验采用多种精子稀释液分别在冷冻前和冷冻后进行激活,结果表明祁连山裸鲤精子在D-15与Kurokura-1中活力较好,达到了(72±5)%,较为接近鲜精的活力。利用10%抗冻剂(DM)来进行裸鲤精液的超低温保存研究,发现D-15保存后的精子活力较高,达到了(35±5)%。     

珍珠龙精子超低温保存的初步研究

为研究适合珍珠龙精子的短期超低温保存方法,比较了不同保存液、保护剂、降温方式、解冻方式对珍珠龙(Scleropages jardini)精液超低温保存后精子活力的影响,初步解释了经超低温短期保存后珍珠龙精子活力明显较鲜精低的原因.结果显示:采用Ringer's液作为保存液,以浓度为16％的二甲亚砜作为保护剂,选取五步法超低温冷冻保存精子[精子缓慢降温至-150℃→液氮面上3 cm(约-170℃),停留4min→液氮面(约-190℃),停留1 min→液氮],40℃水浴解冻,可取得最好的冻后活力,解冻后精子的活力为(36.7±4.1)％.     

鲤、鲢、鳙精子低温短期保存研究

本文对鲤(Cygrinus carpio)、鲢(Hypophthalmichthys molitrix)和鳙(Aristichthys nobilis)精液在2—4℃的短期保存进行了实验研究。筛选出了几种较为理想的稀释保护液配方;确定了精液与稀释液的适宜稀释比例为1:1;研究了抗冻剂二甲亚砜(DMSO)对低温保存条件下精于活力的影响,确定了DMSO的适宜添加浓度为6％左右。鲤精在2—4℃保存10天,活力仍高达70％,少数精子存活时间长达12天;鲢和鳙精子在2—4℃保存7天后活力仍高达60％,达到了生产应用的水平。为水产养殖和鱼类育种研究提供了一种简便易行的精液短期保存技术。     

A Strategy for Sperm Cryopreservation of Atlantic Salmon,Salmo salar,for Remote Commercial‐scale High‐throughput Processing

Sperm cryopreservation is an essential tool for long‐term storage of genetic resources for aquaculture fishes. The goal of this study was to develop an efficient and streamlined protocol for high‐throughput processing for sperm cryopreservation in Atlantic salmon, Salmo salar. The objectives were to evaluate: (1) osmolality of blood serum for determining extender osmolality, (2) effects of extenders for fresh sperm dilution and refrigerated storage, (3) effects of methanol and dimethyl sulfoxide (DMSO) on fresh sperm motility, and (4) motility and fertility after thawing. In this study, sperm samples were collected at a hatchery site in Canada and shipped to a freezing site located 2200 miles (3550 km) away in the USA. Evaluation of three extenders indicated that Mounib solution was suitable for diluting dry sperm for sample processing. Ten percent of methanol or DMSO was less toxic to sperm cells than was 15% within 30 min. Further testing with methanol at 5, 10, and 15%, and sperm solution : extender dilutions (v:v) of 1:1, 1:3, and 1:19 (at concentrations of 5 × 10⁷, 3 × 10⁸, and 1 × 10⁹ cells/mL) indicated that methanol at 5 and 10% showed less toxicity to fresh sperm within 1 h at sperm:extender dilutions of 1:1 and 1:3. Post‐thaw motility of sperm cryopreserved with 10% methanol was significantly higher than that with 10% DMSO, and fertility reflected those results (0–1% in DMSO vs. 38–55% in methanol). Further evaluation of sperm cryopreservation with 10 and 15% methanol at sperm dilution ratios of 1:1, 1:3, and 1:19 indicated that post‐thaw motility in 10% methanol was significantly higher than that in 15% methanol, and post‐thaw fertility in 10% methanol at 1:1 and 1:3 dilution ratios had fertilization rates similar to that of fresh sperm controls. Sperm samples from 12 males cryopreserved with 10% methanol showed male‐to‐male variation in post‐thaw motility (0–36%). Overall, a simplified standard protocol was established for cryopreservation of shipped sperm of Atlantic salmon using extender without egg yolk and yielded satisfactory post‐thaw motility and fertilization rates. This procedure can be readily adopted by aquaculture facilities to take advantage of high‐throughput cryopreservation capabilities at remote service centers. Most importantly, this approach lays the groundwork for an alternative commercial model for commercial‐scale production, quality control, and development of industrial standards. Control of male variability and sperm quality remain important considerations for future work.     

Cryopreservation of sperm in farmed blacklip abalone (Haliotis rubra Leach, 1814)

This study developed a technique of sperm cryopreservation using liquid nitrogen (LN) vapour in farmed blacklip abalone Haliotis rubra through evaluating the following five key factors: (1) cryoprotectant agent (CPA) toxicity; (2) cooling temperature; (3) thawing temperature; (4) sperm to egg ratio and (5) sugar addition, using sperm motility or fertilization rate as quality assessment indicators. The results demonstrated that 6% dimethyl sulfoxide (DMSO) was the best single CPA for sperm cryopreservation in this species. The highest post‐thaw sperm motility was achieved when sperm were exposed to LN vapour for 10 min at 5.2 cm above the LN surface and thawed at 60°C and recovered at 16°C in seawater baths. Post‐thaw sperm motility was found to be significantly higher when 6% DMSO was used in combination with 1% or 2% glucose than 6% DMSO alone. Further evaluation of fertilization rate between these CPAs showed that 6% DMSO+2% glucose achieved the highest fertilization rate of 70% at a sperm to egg ratio of 10 000:1.     

Cryopreservation of sea cucumber Apostichopus japonicus (Selenka) sperm

A simple and convenient method for the cryopreservation of sea cucumber Apostichopus japonicus (Selenka) sperm was tested in the present study. The highest motility (76.7±2.9%) of post‐thawing sperm was obtained in 15% dimethyl sulphoxide (DMSO) with a 1:9 dilution (semen volume to DMSO volume) when 0.5 mL semen–DMSO mixture was frozen at 6 cm above liquid N₂ in a closed styrofoam box. After thawing, sperm cryopreserved in glycerol almost lost motility entirely. Although there was no significant difference in percentage of motile sperm between 15% and 20% DMSO, the duration of sperm motility of 15% DMSO group was longer than that of 20% DMSO group. The motility of post‐thawing sperm enhanced when the dilution ratio of semen increased from 1:1 to 1:9. Morphological changes such as the loss of mitochondria, swollen plasma membrane and broken or rolled‐up tails were observed in post‐thawing sperm using an eosin–nigrosin staining. The fertility of cryopreserved sperm was significantly lower than that of unfrozen sperm. The 10‐fold increase in sperm to egg ratio resulted in double fertility for cryopreserved sperm, and about 70% fertility relative to the control.     

双斑东方鲀精子冷冻保存方法探究

双斑东方鲀(Takifugu bimaculatus)在福建已形成较大规模的养殖产业,但其精卵成熟同步率低、自然交配受精率低等繁殖特点已成为养殖规模化发展的最大制约因素。而精子超低温冷冻保存技术作为直接保存细胞遗传物质的一种有效方法,为双斑东方鲀规模化人工繁育问题的解决提供了方案。研究以复苏后的精子活力为选择指标,开展双斑东方鲀精子冷冻保存方法的研究,对抗冻剂、基础液、精子稀释浓度和降温程序等几个关键影响因素进行了筛选,获得了双斑东方鲀精子的最适冷冻方法:以含5%二甲亚砜(DMSO)的MPRS溶液与精子按1∶1比例稀释,样品在4℃冰箱中平衡30 min,液氮上方10 cm处熏蒸5 min,再下降到5 cm处熏蒸5 min,之后投入液氮。按此方法保存的双斑东方鲀精子在解冻激活后,其活力可达(83±3)%,与相应卵子受精,可得到平均70%的孵化率,可以满足双斑东方鲀规模化人工繁育的需求。研究结果也可为其他东方鲀鱼类的相关研究提供参考。     

Cryopreservation of Persian sturgeon (Acipenser persicus) sperm: effects of cryoprotectants,antioxidant, membrane stabilizer,equilibration time and dilution ratio on sperm motility and fertility

Three experiments were performed to develop protocols for cryopreservation of Persian sturgeon Acipenser persicus, sperm. In the first experiment, sperm from six males was individually split in three subsamples and cryopreserved using Modified Tsvetkova's extender (mT) supplemented with dimethyl sulfoxide (DMSO), methanol (MeOH), glycerol (Gly) and ethylene glycol (EG) at concentration of 5%, 10%, 15% and 20%. In the second set of experiments, the effects of six equilibration times (0, 5, 10, 20, 40 and 60 min) and dilution ratios (volume sperm: volume extender 1:0.5, 1:1, 1:2, 1:3, 1:5 and 1:10) and the additive advantage of bovine serum albumin (BSA; 0, 2.5, 5 and 10 mg mL^?1) and ascorbic acid (0, 2.5, 5 and 10 U mL^?1), on the post‐thaw survival of sperm (triplicate set of six fish) were evaluated. Then, sperm was diluted in 1:1 mT extender with 10 mg mL^?1 BSA with selected cryoprotectants (15% MeOH and 10% DMSO) for 5 min. After a month of storage in liquid nitrogen, post‐thawed sperm motility; fertilization and hatching rate and viability of derived larvae were measured (Exp.3). Evaluation of cryoprotectants efficiency showed that MeOH 15% and DMSO 10% were suitable for cryopreservation of Persian sturgeon sperm. Gly and EG resulted in very low post‐thaw motility rates even at lowest concentration. No significant difference was observed among the four different equilibration times (0, 5, 10, 20 min) (P > 0.05) although higher equilibration times than 20 min resulted low post‐thaw motility (P < 0.05). The motility of frozen–thawed sperm did not significantly change when dilution ratio was increased from 1:0.5 to 1:3 (P > 0.05). However, higher dilution ratios (1:5 and 1:10) reduced the percentage of motile sperm. Supplementation of the cryoprotectant solution with 10 mg mL^?1 BSA significantly improved post‐thaw motility (P < 0.05), but ascorbic acid did not improve post‐thaw motility (P > 0.05). The results of experiment 3 showed that the highest fertilization (30.2 ± 5.75) and hatching rates (28.2 ± 5.25) were observed when samples were frozen with 15% MeOH (P > 0.05). Our study indicates that the use of mT extender consisting of 10 mg mL^?1 BSA in 15% MeOH diluted with sperm at 1:1 ratio for 5 min can be recommended cryopreservation method for Persian sturgeon sperm.     

Transport and cryopreservation of sperm of the common snook, Centropomus undecimalis (Bloch)

Sperm were collected in Florida from wild common snook, Centropomus undecimalis (Bloch), and were shipped to Louisiana State University for analysis and cryopreservation. Threshold activation of sperm (10% motility) occurred at 370 mOsmol kg^?1, and complete activation occurred at 680 mOsmol kg^?1. These values were significantly different. Sperm samples stored at 1°C in Hanks' balanced salt solution (HBSS) or in 0.6% NaCl solution at 200 mOsmol kg^?1 retained motility for as long as 22 days. Mean motility remained above 50% for 9 days for sperm stored in HBSS and for 7 days for sperm stored in NaCl solution. Sperm exposed to 5% dimethyl acetamide (62±10%; mean±SD), 10% dimethyl sulphoxide (DMSO) (39±16%), 5% glycerol (26±5%) or 10% glycerol (6±2%) for 30 min had significantly lower motility than did unexposed sperm (89±9%). When used as a cryoprotectant, samples frozen with 5% or 10% DMSO or 5% methanol had significantly higher post‐thaw motility than did samples frozen with other cryoprotectants. Sperm cryopreserved with 10% DMSO (38±12%) had significantly higher post‐thaw motility than did sperm cryopreserved with 15% DMSO (19±10%) or 20% DMSO (4±4%). There were no significant differences in hatch rates of eggs fertilized with fresh sperm (54±29%) or cryopreserved sperm (41±35%). Survival to first feeding was not different between fish produced with fresh sperm (37±30%; range, 0–86%) or with thawed sperm (24±29%; 0–77%). Transport of sperm to a cryopreservation laboratory and back to a hatchery for thawing and use enabled collaboration between groups with specific expertise and provides a model for the application of cryopreservation by transport of fresh and frozen samples.     

High‐throughput Cryopreservation of Sperm from Sex‐reversed Southern Flounder,Paralichthys lethostigma

The Southern flounder, Paralichthys lethostigma, is a valuable aquaculture fish with established markets in the USA. All‐female production in this species is an important technology for aquaculture because the females usually have body sizes twice those of males at the same age, and sex‐reversed males (genotypic XX neomales) are used for all‐female production by crossing with genetically normal females. However, sperm volume from the neomales is usually small (<0.5 mL) and limits their application for all‐female fish production. Cryopreservation of sperm from these sex‐reversed neomales will provide access on demand with increased efficiency to extend the application of neomales. The goal of this study was to develop a protocol for cryopreservation of sperm from the Southern flounder by using an automated high‐throughput processing system. The objectives were to: (1) determine the effect of osmolality on activation of sperm motility; (2) evaluate the effect of extender solutions on sperm motility capacity; (3) evaluate the acute toxicity of cryoprotectants (dimethyl sulfoxide [DMSO], propylene glycol, and polyethylene glycol) on sperm motility, and (4) estimate the effect of cooling rate on sperm cryopreservation and post‐thaw fertilization. Sperm motility was activated when osmolality was 400 mOsmol/kg or higher. Of the three extender buffers tested, HEPES4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid (HEPES) at 300 mOsmol/kg resulted in better protection for sperm motility than did Hanks' balanced salt solution and Mounib solution at 300 mOsmol/kg during 7 d of refrigerated storage. After 30 min equilibration with the cryoprotectant of 15% DMSO, sperm motility was 24 ± 21% (fresh sperm motility without any cryoprotectants was 42%). After cooling at a rate of 20 C/min, post‐thaw sperm motility was 8 ± 5% and fertilization was 63 ± 40% evaluated at the 32–64 cell stage (5 × 10⁵ sperm per egg). Overall, a protocol was developed for sperm cryopreservation in the Southern flounder with high‐throughput processing, which provides a tool to preserve the valuable genetic resources from neomale flounders, and enables germplasm repository development for the Southern flounder.     

Cryopreservation of sperm from spotted wolffish

The effects of different concentrations of cryoprotectant (dimethyl sulfoxide; DMSO), cooling rate and straw size on the post-thaw motility of frozen sperm from spotted wolffish, Anarhichas minor, were studied. There was no significant difference in the post-thaw motility of sperm treated with three different concentrations of DMSO (10, 20 and 30%). Similarly, there was no significant difference in the post-thaw motility of spermatozoa when using different freezing rates (i.e. distance of straws from the surface of liquid N₂, 4.7, 5.5 and 7.1°C min⁻¹) and the straw size (0.5 and 1.0 ml) did not affect survival. The cryopreservation of sperm can be used to make up for the frequent lack of sperm and/or the unsynchronised timing of sperm production in spotted wolffish males and the ovulation time in females. The results show that sperm from spotted wolffish can be frozen to secure access to viable sperm, but further experiments are needed in order to reveal the effect of different parameters on the post-thawing mortality and define the optimum conditions for cryopreservation.