Coculture of bovine demiembryos prior to freezing.

Pregnancy rates after transfer of frozen/thawed bisected embryos, demiembryos, have until now been very low. In the present study it was attempted to improve the freezability rate of demiembryos by culturing them on a monolayer of bovine oviduct epithelial cells (BOEC) prior to freezing. The cultured frozen/thawed demiembryos showed a lower developmental rate than intact embryos. The pregnancy rate (23%) following transfer was not different from the pregnancy rate after transfer of unfrozen demiembryos (26%). The calving rate (4%), however, was significantly lower than the calving rate after transfer of fresh demiembryos (23%). Although the overall pregnancy rate achieved in this study was low, it can be concluded that a co-culture period upon BOEC prior to freezing does not improve the viability of frozen demiembryos.     

牛孤雌激活囊胚冷冻复苏后胚胎存活率和胚胎质量

使用2种不同的冷冻载体冷冻保存牛孤雌囊胚,并且使用差异染色的方法计数囊胚细胞数。结果显示,开放式毛细玻璃管(GMP)和冻精管(Straws)冷冻牛孤雌囊胚复苏后囊胚孵出率存在显著性差异(GMP法为70.29%,冻精管法为27.31%,P0.05)。差异染色结果显示,牛囊胚冷冻复苏后囊胚细胞数目为91.37,而对照组(正常孤雌囊胚)囊胚细胞数目为93.70,两者差异不显著(P0.05),并且前者内细胞团数(ICM)与滋养层细胞数(TE)比例为0.23,而后者为0.24,差异不显著(P0.05)。结果表明,GMP法更适合冷冻保存牛孤雌囊胚,并且其冷冻复苏后囊胚的孵出率达到70.29%。同时使用GMP冷冻囊胚对囊胚细胞的损伤较小。     

Effects of various cryoprotectants on the survival of mouse embryos cryopreserved by the quick freezing method

The effects of concentrations of glycerol, ethylene glycol or dimethylsulphoxide (DMSO) in the presence of either 0.25 M lactose or sucrose on the post-thaw survival of mouse quickly-frozen compacted morulae were studied. In this method, the embryos were directly frozen in liquid nitrogen (LN2) vapor at approximately -170 degrees C for 2 min before being plunged into LN2. High survival rates of frozen-thawed embryos were obtained when the freezing medium contained 3 M ethylene glycol with either 0.25 M lactose or sucrose (76.5 and 70.2%, respectively). When the embryos were frozen in glycerol, significantly high survival was obtained with 3 M glycerol + 0.25 M sucrose (73.5%, P less than 0.001). However, a freezing medium containing DMSO with either sugar gave lower survival rates. At a higher concentration of 4 M, ethylene glycol with 0.25 M lactose gave significantly higher survival rate than glycerol or DMSO (P less than 0.05). Significantly higher rates were obtained at 2 M with all 3 cryoprotectants when the freezing medium contained lactose rather than sucrose (P less than 0.05). This study showed that glycerol and ethylene glycol were effective cryoprotectants in the quick freezing of mouse embryos, while DMSO was less effective. In addition, the protective effects of these cryoprotectants are affected by their concentrations and the type of sugar used.     

浅析如何提高仔猪成活率

提高仔猪成活率,对养猪行业来说是最关键的一个环节,养好仔猪是培育优良种猪、生产肉猪、降低养猪成本的关键.由于哺乳仔猪生长发育快,生理上不成熟,造成难饲养,成活率低,因此,应认真做好哺乳仔猪的每一项管理工作.     

High in vitro survival rate of sheep in vitro produced blastocysts vitrified with a new method and device

Background: To advance the use of embryo vitrification in veterinary practice, we developed a system in which embryo vitrification, warming and dilution can be performed within a straw. Ovine in vitro produced embryos(IVEP)were vitrified at either early(EBs: n = 74) or fully expanded blastocyst stage(FEBs: n = 195), using a new device named "E.Vit", composed by a 0.25-m L straw with a 50-μm pore polycarbonate grid at one end. Embryos at each stage(EBs and FEBs) were vitrified by either Two-step(TS) or Multi-step(MS; 6 different concentrations of vitrification solutions) protocol. Non-vitrified embryos(n = 102) were maintained in in vitro culture as a control.Warming consisted of placing the straws directly into 1.5 m L tubes containing a TCM-199 solution with three decreasing concentrations of sucrose. Blastocyst re-expansion, embryo survival and hatching rate were evaluated at2, 24 and 48 h post warming. The number of apoptotic cells was determined by TUNEL assay.Results: Blastocyst re-expansion(2 h) after warming was higher(P 0.05) in FEBs group, vitrified with the MS and TS methods(77.90% and 71.25%, respectively) compared with the EBs group(MS: 59.38% and TS: 48.50%,respectively). Survival rates of vitrified FEBs after 24 h IVC were higher(P 0.001) in both methods(MS and TS) than vitrified EBs(MS: 56.25%; TS: 42.42%) and was higher(P 0.05) in the MS method(94.19%) compared with those in TS(83.75%). After 48 h of culture the hatching rate for FEBs vitrified in MS system(91.86%) was similar to control(91.89%), but higher than FEB TS(77.5%) and EBs vitrified in MS(37.5%) and TS(33.33%). Number of apoptotic cells were higher in EBs, irrespective of the system used, compared to FEBs. The number of apoptotic cells in FEBs vitrified with MS was comparable to the control.Conclusions: A high survival rate of IVP embryos can be achieved by the new "E.Vit" device with hatching rates in vitro comparable with control fresh embryos. This method has the potential for use in direct embryo transfer in field conditions.     

Effect of zearalenone on the growth of mouse embryos from blastocysts to the egg cylinder stage in vitro

Embryos were harvested at the blastocyst stage from nontreated outbred mice and were grown in vitro for 4 days. Embryos cultured in control medium hatched and grew to the egg cylinder stage. Purified zearalenone (ZEN) added to the culture medium at concentrations of 8.5 to 68 micrograms/ml decreased the number of embryos growing, with a 50% decrease in the number growing in 32 micrograms of ZEN/ml of medium. Embryos growing in ZEN had decreased numbers of cells derived from the inner cell mass, normal growth of the trophoblast, less cellular differentiation than was seen in control embryos, and increased numbers of phagosomes. Undifferentiated cells of the inner cell mass of control and treated embryos were of the same size, as determined by morphometric analysis. Addition of 25 micrograms of estradiol/ml of culture medium caused no decrease in number of embryos growing or in embryonic size. Saturation of culture medium with ZEN (68 micrograms/ml) did not inhibit the growth of a tissue culture line of goat synovial cells. Seemingly, ZEN at concentrations near saturation inhibited the growth of mouse embryos in vitro. This effect was not duplicated with similar concentrations of estradiol and was not manifested in culture-adapted cells.     

浅谈如何提高犊牛成活率

抓好犊牛的饲养管理,提高犊牛成活率,培养健康犊牛,是提高牛群质量、创建高产牛群的重要基础。提高犊牛成活率,无论对规模化养殖,还是个体养殖户来说,在发展生产、提高经济效益方面都具有十分重要的意义。     

The effects of vitrification after equilibration in different concentrations of cryoprotectants on the survival and quality of bovine blastocysts

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.     

如何提高雏鸭成活率

雏鸭一般指0－28日龄的鸭，雏鸭调节体温的能力和消化能力弱，抗病力差，敏感性高，但生长快，新陈代谢旺盛，育雏阶段的培育工作至关重要。     

Effects of resveratrol treatment on mitochondria and subsequent embryonic development of bovine blastocysts cryopreserved by slow freezing

This study evaluated the effects of cryopreservation by slow freezing on the mitochondrial function, DNA integrity, and developmental ability of bovine embryos and examined whether resveratrol treatment of the frozen‐thawed blastocysts improved embryonic viability. In vitro produced bovine embryos were subjected to slow freezing. After thawing, the ATP content and mitochondrial DNA integrity (mtDNA), determined by real‐time PCR targeting short and long mitochondrial sequences, was found to be lower in frozen‐thawed embryos than in fresh embryos, and mtDNA copy number was significantly reduced during the 24‐hr incubation post warming. Furthermore, immunostaining against double‐strand DNA revealed DNA damage in frozen‐thawed embryos. When frozen‐thawed embryos were incubated in the medium containing 0.5 µM resveratrol, SIRT1 expression, and survival rate of the embryos significantly improved compared with the vehicle‐treated embryos. In addition, cell‐free mtDNA content in medium was higher in case of resveratrol‐treated embryos than of vehicle‐treated embryos. In conclusion, slow freezing affects mitochondrial integrity and function in the blastocysts. In the frozen‐thawed embryos, mitochondria were removed during post‐thawing incubation and resveratrol enhanced the process, resulting in improved survivability of the embryos.     

提高仔兔成活率的技术措施

通过对种公、母兔的严格选种及培育，并根据仔兔的生理特点，从闭眼期、开眼期和断乳期提出严格细致的日常管理技术措施，达到提高仔兔成活率的目的。     

如何提高我省桑树嫁接成活率

湖南省桑树嫁接一般多采用袋接与撕皮根接。对于如何提高嫁接苗的成活率 ,要认真抓好以下几个方面的关键技术。1　加强接穗管理1 .1　及时剪取接穗近年来 ,湖南省气温最低的天气一般在1 2月中旬 ,广东桑、早生桑等休眠期短的桑品种 ,发芽时间比往年要略为提早 ,2 0 0 1年我所栽植的苗 33在 1 2月下旬就已开始萌动。因此要随时注意观察 ,一定要抢在萌动前将穗条采下来贮藏 ,才能保证嫁接的成活率。1 .2　合理贮藏穗条用于嫁接的穗条 ,要经过一定时间的适当贮藏 ,使穗条的含水率控制在合理的范围内 ,才有利于提高嫁接苗的成活率。据统计 ,穗条…     

提高仔猪成活率“十要点”

<正>一、产仔准备为了确保初生仔猪和母猪健康,应在产前做好充足的准备,待产母猪在预产前一周进入产仔舍时,产仔舍应清洁、卫生、干燥而且空气新鲜、温度和湿度适宜,为此应搞好以下工作。1.设施、设备和其他用具的检修和消毒。预产10天前严格检修产仔舍墙壁、房顶、门窗、通风口等并通过相应的方式严格清扫、清洗、消毒,以做到既保持产仔舍内清洁卫生又防止贼风入侵,同时也为以后温度和湿度调控打下坚实基础。2.妊娠母猪进入产仔舍。待产母猪应在预产期前一周进入产仔舍,为此应在预产前8～9天通过增温     

提高仔猪成活率的技术措施

初生仔猪因体温调节机能尚未健全,主动免疫系统发育及功能不健全,尚不能主动抵抗病原微生物的侵袭,胃肠消化能力差及患缺铁性贫血而极易死亡。据统计,约20％～25％的仔猪死于断奶前。为提高仔猪成活率,可采取以下措施。