首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 797 毫秒
1.
试验以Ⅹ期种蛋为实验材料,研究了蛋清抽取量和蛋壳钙质开口对Ⅹ期鸡胚体外发育的影响.试验结果表明:(1)在小头抽取1mL和3mL蛋清后,其孵化率分别为37.9%和50.0%,抽取1mL蛋清组的孵化率显著低于抽取3mL的蛋清组(P<0.05).(2)Ⅹ期鸡胚大头顶端蛋壳钙质层开直径为0.5cm的圆孔后,孵化率仅为15.0%,较对照组(70.0%)明显下降(P<0.01).从发育过程看,开口组鸡胚的死亡主要集中在孵化15d之后,而且死亡鸡胚主要表现为气室显著增大,胚体体积明显缩小,质地变硬.据此推测,开口组鸡胚的死亡可能主要是鸡胚在孵化过程中水分丧失所致.  相似文献   

2.
试验以3日龄种鸡胚蛋为实验材料,通过在小头抽取不同量的蛋清和在大头顶端开3种直径分别为0.5、1.0、1.5em圆孔的方法对3日龄鸡胚原壳体外培养进行研究。结果表明:(1)抽取9ml蛋清后,鸡胚的发育受到的影响最大,孵化率为33.3%,明显低于3“和6ml组(P〈0.01);抽取3ml和6ml蛋清对3日龄鸡胚的影响较小(P〉0.05),孵化率分别为74.3%和76.5%。(2)在小头抽取6ml蛋清后再在大头顶端开直径分别为0.5、1.0、1.5cm的圆孔,以开孔直径为0.5cm孵化率最高,随着开孔直径增大,鸡胚的孵化率呈现极显著下降的趋势。  相似文献   

3.
通过原壳体外培养和抽蛋清的方法,就胚龄、蛋清抽取量对鸡胚发育的影响进行了研究。结果表明:①0日龄鸡胚抽取1mL、3mL和6mL蛋清后,其孵化率分别为38.6%,30.35%和8.6%。抽取蛋清1mL组(P<0.01)和3mL组种蛋(P<0.05)的孵化率明显优于抽取6mL组。②对3日龄鸡胚,抽取9mL蛋清后,鸡胚的发育受到的影响最大,其孵化率仅为33.3%,明显低于3mL和6mL组(P<0.01);而抽取3mL和6mL蛋清对3日龄鸡胚的影响较小,其孵化率仍高达74.3%和76.5%。③抽取6mL蛋清并在大头顶端开直径为1.0cm的圆孔进行鸡胚原壳体外培养获得成功,3日龄鸡胚的孵化率为18.5%。  相似文献   

4.
在孵化生产中经常出现鸡胚啄壳前死亡的现象,死亡率高达12%。现将发生该现象的原因及预防措施介绍如下: (一)鸡胚死亡的原因 1.鸡胚嘴尖离壳较远,发育好的鸡胚头部都弯曲于翅膀下,且蛋壳内大部分空间被胚体所占有,导致种胚头部活动极为有限,只能作横向短距离运动。此外,胚胎由尿囊呼吸过渡到肺呼吸,需氧量增多,致使蛋内严重缺氧。因此,嘴尖离壳远的和一些活动力差的鸡胚就不可能啄破蛋壳得到氧气,致使发育正常的鸡胚啄壳前被闷死(见图1)。  相似文献   

5.
将发育至第X期的鸡胚转和代用蛋壳内,分为4组分别添加蛋清至满或空余一定气室,正立或倒置孵化,观察鸡胚发育至“蚊虫珠”期胚胎的比较。结果发现鸡胚仅在代用蛋壳气室充盈无气泡、并与壳膜充分接触量,85%(34/40)的鸡胚能发育至“蚊虫珠”期。  相似文献   

6.
1.将72小时的家鸡胚胎移至无壳培养或“代用”蛋壳中,以研究培养这些鸡胚至“出雏”的可能性。 2.在孵育的前半期摇晃鸡胚培养可促进鸡胚生长。 3.移至鸡的或其他禽的“代用”蛋壳中的鸡胚都成功地“出雏”。 4.在代用蛋壳中可形成正常的绒毛尿囊膜,从而能形成有功能的蛋白囊并实现蛋壳的重吸收。 5.在“代用”蛋壳中生长的鸡胚略小于对照鸡胚,但其他方面均正常。 6.本技术为遗传工程实验提供了机会。  相似文献   

7.
旨在为小鼠和猪多能性干细胞嵌合体制作提供参考,探讨胚胎干细胞(Embryonic stem cells或Embryonic germ cells,ES/EG)显微注射及受体胚胎发育时期等对胚胎发育的影响。对小鼠ES细胞和猪EG细胞分别进行研究:(1)将小鼠ES细胞分别注入小鼠桑椹胚和囊胚,比较不同发育时期受体胚胎体外培养的发育率和孵化率,以及注射胚胎和未注射胚胎体外培养的发育率和孵化率。结果表明,显微注射后的桑椹胚体外培养发育率和孵化率分别为94.7%和70.2%,囊胚率分别为84.6%和80.8%,注射后桑椹胚体外培养发育率极显著高于囊胚(P0.01),但注射后囊胚体外培养孵化率极显著高于桑椹胚(P0.01);未注射胚胎(注射胚胎)的体外培养发育率和孵化率分别为96.6%(89.9%)和67.8%(75.2%),未注射胚胎发育率极显著高于注射胚胎(P0.01),但注射胚胎孵化率极显著高于未注射胚胎(P0.01)。(2)将猪EG细胞分别注入猪桑椹胚、早囊、囊胚及孵化囊胚,比较不同发育时期受体胚胎移植后妊娠率以及注射胚胎和未注射胚胎体外培养的孵化率,并对猪EG细胞显微注射针和固定针的规格进行了探讨。结果表明,显微注射的桑椹胚、早囊及囊胚移植后妊娠率为67%,而显微注射的孵化囊胚移植妊娠率为0,桑椹胚、早囊及囊胚移植后受体母猪妊娠率极显著高于孵化囊胚(P0.01),由桑椹胚、早囊及囊胚注射后移植获得了两头嵌合体仔猪;显微注射和未显微注射的猪胚胎其孵化率分别为47.54%和72.97%,未注射胚胎孵化率极显著高于注射胚胎(P0.01)。确定猪EG嵌合体制作过程中,注射针外径约为30μm,内径约为25μm;固定针外直径约为130~150μm,内径约为40μm。嵌合体制作时,胚龄宜早不宜迟,桑椹胚显微注射更易操作,而且导入的时期较早,ES/EG细胞在嵌合体组织中可以有很高的贡献率,故选择桑椹胚进行注射。在本试验条件下,显微注射对小鼠胚胎发育影响不大,对猪胚胎影响较大,说明猪胚胎显微注射条件需要进一步优化。  相似文献   

8.
大雁的蛋壳比鸡鸭鹅等一般家禽的蛋壳厚而且硬,在正常孵化条件下,胚胎出壳困难,孵化率只有50%-60%。为了探讨提高大雁种蛋孵化率的有效方法.太试验共分为软化蛋壳助产组、敲破蛋壳助产组和对照组3个组,3组种蛋的数量相等.重量、大小和形态等相关形状差异不显著。预试期25天。预试期统一进行了种蛋消毒、预热、温湿度控制、翻蛋、照蛋和凉蛋等操作。预试期结束后,软化蛋壳的操作方法是:将6%的醋酸溶液喷洒在蛋壳表面,以喷湿整个蛋表面不滴漏为宜,每天1次,直至破壳。敲破蛋壳助产技术要领是:先清洗消毒手和剪刀等接触胚蛋及雏雁的用品.将尿囊血管已经枯萎、内壳膜发黄的胚蛋用剪刀等在蛋钝部轻轻打开,拨开蛋壳1/3左右.并用手将雏雁的头轻轻拉出,放入出雏器内令其自行出壳。试验结果.软化蛋壳助产组和敲破蛋壳助产组的孵化率分别是95.1%和95.0%.分别比对照组的59.8%提高了35_3%和35.2%,差异极显著。软化蛋壳助产组和敲破蛋壳助产组的孵化率差异不显著。  相似文献   

9.
在代用蛋壳中孵化鸡胚   总被引:19,自引:3,他引:16  
本实验将正常孵化72h的鸡胚转移到代用蛋壳内培养。鸡胚的存活率在第10d和第18d时分别是100%和90%(23/25)。孵化率为52%(13/25)。  相似文献   

10.
试验对牛胚胎体外生产技术中的体外受精液、精卵共育时间、血清和培乔液等影响早期胚胎体外发育的因素进行了研究。以BO(Brackett & Oliphant)和BM(BO:成熟培养液=3:2)作为受精液,受精卵的囊胚发育率分别为26.0%和15.0%;精卵共育时间以9-12h为宜;受精卵在含血清FBS或OCS培养液中的专胚发育率分别为26.4%或29.9%,明显高于在无血清培养基中的囊胚发育率(10.3%);TCMl99、mBECMaa、mSOFaa3种胚胎培养液均能支持受精卵的体外发育,在其中培养受精卵囊胚发育率分别为18.O%、30.7%和29.2%。试验结果表明:精卵于BM受精液中共育9~12h后,将假定受精卵置于添加5%OCS的mBECMaa或mSOFaa培养液中培养,能显著提高体外生产胚胎的囊胚发育率。  相似文献   

11.
试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。  相似文献   

12.
Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.  相似文献   

13.
14.
1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.  相似文献   

15.
Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.  相似文献   

16.
Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.  相似文献   

17.
Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.  相似文献   

18.
Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.  相似文献   

19.
The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.  相似文献   

20.
<正>1.INTRODUCTION Ensuring transportation network security is one Of the most daunting challenges confronting homeland security agencies today.Significant research has been dedicated.To model and analyze the vulnerability of transportation systems,while notably fewer studies propose specific strategies for deploying defensive technologies to safeguard these systems.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号