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1.
The aim of this study was to evaluate the viability in the effect of open pulled straw (OPS) vitrification procedure of sheep embryos after direct transference. Embryos were produced in vivo and cryopreserved in slow freezing or OPS vitrification. The survival rates of cryopreserved embryos were compared to non-frozen standard pattern. In a first set of experiments, embryos at morula and blastocyst stages were dived in ethylene glycol (1.5 M) and frozen in an automatic freezer. After being thawed, they were directly or indirectly transferred to ewes recipient. A second group of embryos were drawn into OPS and plunged into liquid nitrogen after being exposed at room temperature for 1 min and 45 s in 10% EG plus 10% dimethyl sulphoxide (DMSO), then again for 30 s in 20% EG + 20% DMSO + 0.5 M sucrose. After being warmed, embryos were also directly transferred using a French mini straw as the catheter for the transplantation process or after in vitro dilution of cryoprotectants (two-step-process). No significant difference was observed among fresh, frozen or vitrified embryos on pregnancy rate (50.0%, 38.6% and 55.8%). However, when we evaluated only the direct transference, the pregnancy rate of OPS vitrified embryos was higher than that of frozen embryos (57.1% vs 34.8%) (p = 0.07). In addition, vitrified morulae had a higher pregnancy rate than the one with frozen embryos (64.0% vs 38.9%) (p = 0.07). Finally, our results indicate that OPS vitrification technique in association with direct transference improves the viability of sheep embryos with potential applications to field conditions.  相似文献   

2.
An in vitro infectivity assay was used to examine five cryoprotectants for their suitability for preserving Theileria parva sporozoites. All five were capable of preserving T. parva sporozoites through freezing, the optimal concentrations being 7.5% for glycerol, 5% for dimethyl sulphoxide (DMSO), poly (vinylpyrrolidone) (PVP) and poly(ethylene glycol) (PEG), and 2.5% for hydroxyethyl starch (HES). When the five cryoprotectants were compared at their optimal concentrations, using a modification of the standard method of stabilate preparation, glycerol was significantly better than the others (p<0.05). Measurement of the effects of each cryoprotectant on the osmolality of the media revealed that glycerol and DMSO elevated the osmolality significantly (p<0.05). Resuscitation of glycerol-preserved sporozoites required the presence of glycerol in the diluent to maintain infectivity. Studies on the effects of equilibration time in glycerol on the infectivity of sporozoites showed that those frozen immediately after mixing (2 min) were as infective as those frozen after 60 min of equilibration.  相似文献   

3.
The embryos were frozen and thawed in Cassou minipaillette by a rapid method. Embryos with cryoprotective agent (glycerol, 1.5 M) were placed directly into the freezing medium at the temperature of -6 to -7 degrees C, frozen after seedling at the temperature decrease by 0.3 to 0.5 degrees C per minute to the temperature of -32 degrees C and then transferred directly into liquid nitrogen. They were thawed in a bath warm 20 to 37 degrees C. After thawed the cryoprotective agent was evacuated in 1.1 M sucrose. The best-quality embryos were selected for freezing. Out of these 366 thawed so far, with average survival of 74.31%. The total of the 268 thawed embryos were transferred ipsilaterally, by a non-surgical method, to 190 synchronised heifers, out of which 105 (55.26%) got in calf. Rapid freezing method based on 1.5 M of glycerol and thawing at the presence of 1.1 M sucrose proved effective and suitable for practice, as not only sufficient reviviscence of embryos and their survival in womb are guaranteed, but also a substantial shortening of the freezing as well as thawing process.  相似文献   

4.
1. The effects of various cryoprotectants (glycerol, dimethyl‐sulphoxide (DMSO), methylformamide and ethylene glycol) of the same molarity on preserving the morphology of frozen and thawed fowl spermatozoa (especially midpiece and acrosome) were examined under the light (LM) and scanning electron microscope (SEM) to determine the most suitable.

2. Under LM, the mean respective increases in sperm deformity in semen diluted with ethylene glycol, methylformamide, glycerol and DMSO were 4·5, 4·9, 5·0 and 6·5 percentage points.

3. Under SEM, the mean respective increases in acrosomal deterioration in semen diluted with glycerol, ethylene glycol, DMSO and methylformamide were 6·6, 8·8, 13·1 and 31·2 percentage points.

4. From these results, it appears that glycerol is superior to ethylene glycol DMSO and methylformamide as a cryoprotectant.

  相似文献   

5.
哺乳动物胚胎冷冻保存效果受冷冻保护剂、冷冻方法、解冻方法等多种因素影响,其中冷冻方法是一个关键性因素.目前胚胎冷冻方法主要有常规慢速冷冻法和玻璃化冷冻法两种.常规慢速冷冻法是指利用甘油、乙二醇等做冷冻保护剂通过缓慢降温的方式进行胚胎冷冻;玻璃化冷冻法是指利用高浓度的冷冻保护剂通过快速降温的方式进行胚胎冷冻.与常规慢速冷冻法相比,玻璃化冷冻法简化了操作过程,大大缩短了操作时间,不需昂贵的程序控制冷冻仪.  相似文献   

6.
Cryosurvival of cells is reduced if the cooling rate used is suboptimal. If cells cool too rapidly, intracellular water will freeze, causing intracellular ice crystals. However, if spermatozoa are cooled too slowly, excessive cellular dehydration occurs, causing irreversible damage to cellular compartments. In addition, cryoprotectants are added to the freezing diluent to protect cells from damage during cryopreservation. This study was conducted to determine the optimal cooling rate for stallion spermatozoa frozen in the presence of three different cryoprotectants. Spermatozoa were frozen in a skim milk, egg yolk diluent containing 4% glycerol, and ethylene glycol or dimethyl formamide at 10 different cooling rates ranging from 5°C/min to 50°C/min. The percentage of viable spermatozoa was higher for spermatozoa cooled at 10°C/min than at 50°C/min (P < .05). Spermatozoa frozen using glycerol as the cryoprotectant had higher percentages of motile and progressively motile spermatozoa compared with spermatozoa frozen using the other two cryoprotectants (P < .05). In conclusion, the cryosurvival of stallion spermatozoa is similar when cooling rates of 5°C/min to 45°C/min are used, and when 4% cryoprotectant is used, glycerol is a more effective cryoprotectant than ethylene glycol or dimethyl formamide.  相似文献   

7.
鸡胚精原干细胞体外保存能力的研究   总被引：4，自引：1，他引：4  
采用二酶3步法获取孵化第19 d的鸡胚精原干细胞（SSCs）,比较在快速冷冻条件下3种冷冻保护剂（DMSO、乙二醇、甘油）在3个浓度5%、10%、15%条件下对鸡胚精原干细胞的冷冻保存效果进行研究。结果显示：（1）当DMSO的浓度为5%、10%及15%时,复苏后细胞存活率分别为73.1%、88.6%和74.8%,三者差异显著（P〈0.05）;而10%DMSO保存精原干细胞的存活率、复苏后培养细胞生长和集落形成均显著高于其它2个浓度;当乙二醇浓度为5%、10%和15%时,复苏后细胞存活率分别为69.4%、83.1%和65.2%,三者差异显著（P〈0.05）;复苏后无论饲养层存在与否,SSCs均能增殖,但未有AKP阳性集落生成;当甘油浓度为5%、10%、15%时,复苏后细胞存活率均小于15%,三者差异不显著（P〉0.05）;复苏后细胞存活时间极短,仅存活12 h左右;（2）当在10%DMSO浓度条件,复苏后SSCs在有饲养细胞层的条件下,培养5 d形成集落,表明10%DMSO是鸡胚精原干细胞适宜的冷冻保护剂。  相似文献   

8.
采用两步酶解和差异贴壁法分离、纯化鸡精原干细胞(SSCs),比较了6种冷冻保护液对其冷冻保存效果,结果表明:FBS浓度为10%时,10%DMSO与10%甘油解冻后细胞存活率分别为54.05%和37.49%,差异显著(P<0.05);以10%DMSO为冷冻保护剂时,FBS浓度从10%增加到20%,解冻后细胞存活率分别为54.05%和69.06%,差异显著(P<0.05);在冷冻液Ⅰ基础上,添加3种不同浓度的蔗糖溶液,解冻后细胞存活率分别为52.49%、47.65%和51.94%,三者之间差异不显著(P>0.05),且与冷冻液Ⅰ组差异也不显著(P>0.05);将解冻后细胞接种饲养层上培养,除甘油组外,SSCs均能增殖并形成AKP阳性集落,但10%DMSO加上20%FBS组细胞增殖速度和集落数优于其他组合,表明10%DMSO加上20%FBS为鸡SSCs最佳冷冻保护剂。  相似文献   

9.
The chemical toxicity of cryoprotectants to porcine embryos was examined by the evaluation of survival and DNA damage after exposure to cryoprotectants. Porcine blastocysts were exposed to 10% of ethylene glycol (EG), 1,2-propanediol (PD) or glycerol (GLY) for 1 h at room temperature (23-25 degrees C) and then cultured in vitro for 24 h. The survival rates of blastocysts exposed to PD and GLY were significantly lower than those of control blastocysts in which the embryos were exposed to carrier solution without cryoprotectants. Significantly more DNA-fragmented nuclei occurred in the cryoprotectant-exposed blastocysts, compared with the control blastocysts. Moreover, the indices of DNA-fragmented nuclei in the blastocysts without blastocoele re-formation after culture were significantly higher than those with blastocoele re-formation, irrespective of the exposure treatment. These results indicate that the exposure of porcine blastocysts to cryoprotectant decreases the survival rates and increases the DNA-fragmented nuclei in embryos.  相似文献   

10.
This study assessed the effects of cryoprotectant concentration during equilibration on the efficiency of bovine blastocyst vitrification and the expression of selected developmentally important genes. In vitro produced bovine blastocysts were equilibrated in either 7.5% ethylene glycol (EG) + 7.5% DMSO (Va group) or in 2% EG + 2% DMSO (Vb group) then vitrified on Cryotop® sheets in 16.5% EG + 16.5% DMSO + 0.5M sucrose. After warming, embryos were cultured for 48 hr. Re‐expansion, hatching, and the numbers of total and membrane damaged cells were compared among vitrified groups and a control. There was no significant difference between the vitrified groups in survival, cell numbers and the extent of membrane damage. Vitrification increased the number of membrane‐damaged cells in both groups, however, in a greater extent in the Vb group. Vitrification increased (p < .05) the expression of the HSP70 gene in Va but not in Vb embryos. The expression of IGF2R, SNRPN, HDAC1, DNMT3B, BAX, OCT4, and IFN‐t genes were the same in control and vitrified groups. In conclusion, the concentration of cryoprotectants during equilibration did not affect survival rates; however, normal cell numbers could be maintained only by equilibration in 15% cryoprotectants which was associated with increased HSP70 expression.  相似文献   

11.
The effect of addition of linoleic acid-albumin (LAA) to culture medium before freezing on the survival rate of bovine 16-cell embryos after freezing-thawing was investigated. Embryos were incubated in CR1aa containing LAA (0.25 mg/ml) for 4 days after insemination. A conventional slow cooling method was used, in which embryos were cooled at a rate of 0.3 degrees C/min to -30 degrees C in medium supplemented with 1.5 M ethylene glycol and 0.2 M trehalose. The developmental rate to the blastocyst stage of thawed embryos that had been cultured with LAA-containing medium before freezing was higher than that of these cultured without LAA (P<0.05). However, with fresh, non-frozen, embryos that were incubated under the same culture conditions (with and without LAA), no such difference was found.  相似文献   

12.
Movement of water and cryoprotectants through the plasma membrane needs to be accelerated for successful cryopreservation of zebrafish oocytes/embryos, which are much larger than their mammalian counterparts. Aquaporin-3 is a water/solute channel that can transport not only water but also various cryoprotectants. In this study, we attempted to increase the permeability of immature zebrafish oocytes at stage III to water and cryoprotectants by exogenous expression of rat aquaporin-3. Immature zebrafish oocytes were injected with rat aquaporin-3 cRNA and cultured for 5-12 h. Permeability to water and cryoprotectants was then determined based on changes in the volumes of the oocytes in a hypertonic sucrose solution and various cryoprotectant solutions at 25 C. The permeability to water of the aquaporin-3 cRNA-injected oocytes was three times higher than that of intact and water-injected oocytes. The permeability of the aquaporin-3 cRNA-injected oocytes to ethylene glycol, glycerol, propylene glycol, and DMSO was also 2-4 times higher than that of intact oocytes. Thus, the permeability of immature zebrafish oocytes to water and cryoprotectants was enhanced by exogenous expression of aquaporin-3. Cryopreservation of teleost oocytes may be realized through a further increase in permeability.  相似文献   

13.
In the present study, mouse blastocysts were employed to investigate the feasibility and efficiency of stepwise in-straw dilution and direct transfer using the open pulled straw (OPS) method. In experiment I, the effects of various vitrification solutions (VS) on embryo survival were examined. After thawing, the expanded blastocyst rates (97.59 and 95.05%) and hatching rates (80.48 and 78.95%) achieved in the EDFS30 [15% ethylene glycol (EG), 15% dimethyl sulfoxide (DMSO), Ficoll, and sucrose] and EFS40 [40% EG, Ficoll, and sucrose] groups were no different from those (96.15% and 83.33%) of the control group. However, the rates in the EFS30 [30% EG, Ficoll, and sucrose] (87.80 and 55.43%) and EDFS40 [20% EG, 20% DMSO, Ficoll, and sucrose] (95.69 and 70.97%) groups were significantly lower than those (96.15 and 83.33%) of the control group (P<0.05). In the experiment II, the effects of the volume of VS in the OPS on the survival of embryos after in-straw thawing were investigated. When the length of the VS in the column was less than 1 cm, the in vitro viability of embryos thawed by stepwise in-straw dilution was no different among the experimental and control groups. The embryos could be successfully thawed by immersing the OPS in 0.5 M sucrose for 3 min and then 0.25 M sucrose for 2 min. In experiment III, the effect of immersion time of the OPS in diluent (PBS) on the viability of vitrified embryos was investigated. After in-straw thawing, OPSs were immersed immediately in 1 ml PBS for 0 to 30 min. When the immersion time of the OPSs in PBS was less than 12 min, in vitro development of the in-straw thawed embryos was no different from that of the controls. In experiment IV, in-straw thawed blastocysts were directly transferred to pseudopregnant mice to examine their in vivo developmental viability. The pregnancy (91.67%) and birth rates (42.42%) of embryos in-straw thawed and directly transferred were no different from those of the unvitrified controls (90.90 and 40%) and embryos thawed by the conventional method (84.61 and 46.94%). These results demonstrate that mouse embryos vitrified with OPS could be successfully thawed by stepwise in-straw dilution and transferred directly to a recipient and that this method might be a model for field manipulation of vitrified embryos in farm animals.  相似文献   

14.
Improving pregnancy rates associated with the use of cryopreserved human oocytes would be an important advance in human assisted reproductive technology (ART). Vitrification allows glasslike solidification of a solution without ice crystal formation in the living cells. We have attempted to improve the survival rates of oocytes by a vitrification technique using bovine models. In vitro matured oocytes with or without cumulus cells were vitrified with either 15.0% (v/v) ethylene glycol (EG) + 15% (v/v) dimethylsulfoxide (DMSO) + 0.5 M sucrose or 15% (v/v) EG + 15% (v/v) 1,2-propanediol (PROH) + 0.5 M sucrose, using 'Cryotop' or 'thin plastic sticker', respectively. The oocyte survival rates after vitrifying-warming, and the capacity for fertilization and embryonic development were examined in vitro. The rate of embryonic development to blastocyst was significantly higher (P<0.05) in the oocytes vitrified with 15% (v/v) EG + 15% (v/v) PROH + 0.5 M sucrose than in the oocytes vitrified with 15% (v/v) EG + 15% (v/v) DMSO + 0.5 M sucrose (7.4% +/- 4.1 vs. 1.7% +/- 3.0, respectively). Oocytes vitrified without cumulus cells had a higher survival rate after thawing and a superior embryonic developmental capacity compared with oocytes vitrified with cumulus cells. Prolonged pre-incubation time after thawing adversely affected the rates of embryonic cleavage and development. These results indicate that in vitro matured bovine oocytes can be vitrified successfully with the mixture of the cryoprotectants, EG + PROH, the absence of cumulus cells for vitrification does not affect oocyte survival rate after warming, and vitrified and warmed oocytes do not require pre-incubation before in vitro fertilization.  相似文献   

15.
The present study was conducted to examine post-thaw in vitro developmental competence of buffalo embryos cryopreserved by cytoskeletal stabilization and vitrification. In vitro produced embryos were incubated with a medium containing cytochalasin-b (cyto-b) in a CO2 incubator for 40 min for microfilament stabilization and were cryopreserved by a two-step vitrification method at 24℃ in the presence of cyto-b. Initially, the embryos were exposed to 10% ethylene glycol (EG) and 10% dimethylsulfoxide (DMSO) in a base medium for 4 min. After the initial exposure, the embryos were transferred to a 7 µl drop of 25% EG and 25% DMSO in base medium and 0.3 M sucrose for 45 sec. After warming, the embryos were cultured in vitro for 72 h. The post-thaw in vitro developmental competence of the cyto-b-treated embryos did not differ significantly from those vitrified without cyto-b treatment. The hatching rates of morulae vitrified without cyto-b treatment was significantly lower than the non-vitrified control. However, the hatching rate of cyto-b-treated vitrified morulae did not differ significantly from the non-vitrified control. This study demonstrates that freezing of buffalo embryos by cytoskeletal stabilization and vitrification is a reliable method for long-term preservation.  相似文献   

16.
Although embryo cryobanking was applied to Syrian golden and to Campbell's hamsters, no attempt has been made at freezing embryos in Djungarian hamsters. Four‐cell stage embryos were flushed from the reproductive ducts of pregnant females before noon of the third‐day post coitum and frozen in 0.25‐ml straws according to standard procedures of slow cooling. A mixture of permeating (ethylene glycol) and non‐permeating (sucrose) cryoprotectants was used. The thawing was performed by incubating at RT for 40 s followed by 40 s in a water bath at 30.0°C. Most (66.7%) of the non‐frozen four‐cell embryos developed up to the morula stage in rat one‐cell embryo culture medium (R1ECM). The use of hamster embryo culture medium (HECM) yielded fewer morulas (18.2%) during the same 24‐h period of culture. The rate of embryo's surviving the freezing–thawing procedures, as estimated by light microscopy, was 60.7–68.8%. After 24‐h culturing in R1ECM, 64.7% of frozen–thawed four‐cell embryos developed and all of them reached the morula stage. Supplementation of R1ECM with GM‐CSF (2 ng/ml) improved the rate of Djungarian hamster frozen–thawed embryo development: 100% of the four‐cell stage embryos developed, 50% of them achieved the morula stage, and 50% developed even further and reached the blastocyst stage within 24 h of culturing. This study reports the world's first successful transfer of frozen–thawed Djungarian hamster embryos yielding term pups. Taken together, the results of this study demonstrate the possibility of applying some key reproductive technologies, that is, embryo freezing/cryopreservation and in vitro culture, to Djungarian hamsters.  相似文献   

17.
Two-cell stage and blastocyst stage mouse embryos were equilibrated in a medium containing 7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO) for 8–15 min. Vitrification was performed in a medium containing 0.5 M sucrose and either 15% EG + 15% DMSO, 17.5% EG + 17.5% DMSO, or 20% EG + 20% DMSO for 30 s. They were then placed either on a hemi-straw (HS) or a hollow fiber vitrification (HFV) device and vitrified by cooled air inside a 0.5-ml straw. In two-cell embryos, a 100% survival rate was obtained from all groups except the 20% HS group (P > .05). All vitrified two-cell groups showed similar rates of blastocyst development to that of fresh control group (P > .05), except 17.5% and 20% HFV groups, which were significantly lower than the other groups (P < .05). In the blastocyst embryos, the HFV groups were divided into two subgroups (non-collapsed; HFV-NC and collapsed; HFV-C blastocyst). Re-expansion rate in 15% HFV-NC, 17.5% HFV-NC, and 15% HFV-C groups was reduced (P < .05), whereas the rest were similar to control. In conclusion, we established a simplified, reliable, and closed system for HFV vitrification applying hemi-straw, which does not require skilled practitioners.  相似文献   

18.
Cryopreservation of Sheep Primordial Follicles   总被引：3，自引：0，他引：3  
The aim of this study was to evaluate the efficiency of 1 M dimethylsulphoxide (DMSO), ethylene glycol (EG), propylene glycol (PROH) and glycerol (GLY) to cryopreserve primordial follicles. The first evaluation was performed soon after cryopreservation and the second evaluation after 4 days of in vitro culture, using the cryoprotectants that allowed the higher results (higher follicular survival rate) after cryopreservation. The results after follicular isolation (control) and cryopreservation using 1 M DMSO, EG, PROH and GLY showed that the mean number (+/- SEM) of live follicles per millilitre was 3204 (100%) +/- 319.27, 2798 (87%) +/- 239.14, 2492 (78%) +/- 345.8, 448 (14%) +/- 46.3 and 208 (7%) +/- 75.26, respectively. Higher follicular survival was reported when DMSO and EG were used. Control follicles and follicles cryopreserved with these two cryoprotectants were cultured and the percentage of follicular survival was 55% (control), 42% (EG) and 34% (DMSO). Similar results were found between control and follicles cryopreserved with EG. In conclusion, 1 M EG is the most effective cryoprotectant to preserve primordial follicles isolated from ovaries of sheep.  相似文献   

19.
My research awarded includes contributions to cryopreservation and sexing of bovine embryos produced in vitro and in vivo, as follows; (1) In vivo-derived morulae and blastocysts were cryopreserved in the presence of 10% glycerol, and the embryos were transferred into recipients after two-step dilution of glycerol in straw, with a practically acceptable pregnancy rate. (2) The survival rate of 16-cell stage embryos frozen in the medium with ethylene glycol was higher than that with DMSO or 1,2-propanediol. Addition of linoleic acid-albumin to culture medium enhanced the survival rate of post-thaw bovine 16-cell stage in vitro-produced (IVP) embryos. (3) Polarization of cytoplasmic lipid droplets by centrifugation of 2-cell stage embryos was found effective to increase freezing tolerance in 16-cell stage embryos developed from the centrifuged embryos, because blastomeres of 16-cell stage embryos were mostly lipid-free. (4) The usefulness of gel-loading tip (GL-Tip) as a container for ultra-rapid vitrification was demonstrated in IVP embryos from 2-cell to blastocyst stages, with a higher in vitro survival than the conventional two-step freezing. (5) PCR analysis for sexing of in vivo-derived Day-7 embryos indicated that male embryos developed faster and graded higher than female embryos. But such correlation between genetic sex and embryonic development was not found in IVP embryos obtained from individual cows. (6) Addition of 0.1-1.0% deproteinized hemodialysate product from calf blood to culture medium increased the producing efficiency of demi-embryos with good quality. Female embryos rather than male embryos required a longer time to repair after bisection. (7) In vivo-derived bovine embryos after biopsy for sexing by PCR analysis and subsequent vitrification using GL-Tips are available to practical use in the field. (8) Introduction of primer extension preamplification-PCR and purification of DNA product before standard sexing PCR of biopsy samples from Day 3-4 in vitro-derived embryos allowed accurate sex determination, and Day-7 blastocysts developed from Day 3-4 embryos were cryopreserved by GL-Tip vitrification without a loss of their viability. Thus the field application of bovine embryo transfer is in part supported by improvements of technologies in embryo cryopreservation and sex pre-determination.  相似文献   

20.
牛体外受精胚胎一步脱防冻剂冷冻方法的研究   总被引：8，自引：1，他引：7  
为了研究适合于牛体外受精胚胎的一步除防冻剂的冷冻方法，特进行两个试验。试验１分别用１．５Ｍ甘油＋０．２５Ｍ蔗糖、１．５Ｍ乙二醇和１．５Ｍ丙二醇作防冻剂冷冻体外受精后第７天，已发育至囊胚阶段的牛胚胎。使胚胎降温至－７℃后，植冰，然后以０．３℃／分的速率降温至－３０℃，立即将胚胎投入液氮中冷冻保存。在３７℃水中解冻胚胎后，使其直接在含１５％胎犊血清（ＦＣＳ）的磷酸缓冲液（ＰＢＳ）中脱去防冻剂。经体外培养７２ｈ后，３组胚胎的孵化率分别为７７．２７％（１０２／１３２）、７３．２４％（１０４／１４２）、４７．９０％（５７／１１９），第１、２组的孵化率极显著高于第３组（Ｐ＜０．０１），说明用１．５Ｍ丙二醇溶液冷冻的胚胎，在解冻后不宜直接在ＰＢＳ中脱防冻剂。试验２比较用不同浓度（１．０Ｍ０１．５Ｍ，２．０Ｍ）的乙二醇和不同投液氮温度（－２５℃，－３０℃，－３５℃）冷冻胚胎的效果。结果表明乙二醇浓度和投液氮温度对胚胎孵化率均无显著影响（Ｐ＞０．０５），各组胚胎的孵化率变动于７４．４４％－８５．４８％之间。  相似文献   

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