Effect of Embryonic and Maternal Genotype on Embryo and Foetal Survival in Rabbit

The aim of this work was to study the influence of embryonic and maternal genotype of two lines of rabbits selected by growth rate (line R) and litter size at weaning (line A) on prenatal survival. Embryos were recovered at 48 h of gestation from R and A donors (39 and 35 does, respectively) and reciprocally transferred to the oviducts of recipient does to the R (n = 15) and A (n = 14) lines. Each recipient doe received six embryos from line R into one oviduct and six embryos from line A into the other. Recipient does were examined by laparoscopy to determine implantation rate on day 14 and slaughtered on day 25 of gestation to determine the number of live foetuses and the weight of foetuses and placentas. No differences were found between lines in fertilization rate and stage of embryo development at 48 h post‐insemination. Implantation rate was affected by both the embryonic and maternal genotype. While embryos from donor line A had the highest implantation rate (0.78 ± 0.032 vs 0.65 ± 0.036 for line R), recipient line R had a better implantation rate (0.78 ± 0.033 vs 0.64 ± 0.036 for line A). Foetal survival was affected by the embryonic genotype. Embryos from donor line A had a higher foetal survival rate than embryos from donor line R (0.65 ± 0.036 vs 0.53 ± 0.038, respectively) but lower foetal and placenta weights. In conclusion, while embryonic genotype influenced both implantation and foetal survival rate, R embryos had the lowest rates, maternal genotype affected the implantation rate and R recipients may show a greater uterine receptivity during implantation period. Moreover, it must be observed that foetal and placenta weights were significantly affected by embryonic genotype and heavier for R line.     

Embryonic Signals and Survival

The objective of this review is to give an overview of the signaling mechanisms between the conceptus and the mother before implantation. The interactions between the embryo and uterus are complex and essential for normal embryo development and implantation. Problems in the signaling mechanisms are thought to play a significant role in early embryonic mortality since a high rate of embryonic morality occurs during this period. This review will focus on the mechanisms involved in the development of the conceptus and the prevention of luteolysis. It is based primarily on what is known in ruminants but also refers to work in other species such as the mouse and primates.     

Foetal Growth in the Reindeer

In connection with reindeer, slaughter 348 foetuses were collected at different foetal developmental stages and studied together with 20 full-term newborn calves with respect to weight, crown-rump length, metacarpal bone length and appearance of ossification foci. On the basis of these measurements polynomial growth curves were constructed. Weight gain was most rapid during the last trimester of gestation, but total and metacarpal bone length gain showed only minor acceleration towards the end of pregnancy. Ossification was apparent at an age of about 6 weeks. Undernutrition during late winter was observed to retard the foetal growth.     

如何提高幼兔成活率

近来,笔者在养兔技术跟踪服务过程中,发现养兔专业户养幼兔成活率较低,特别是夏季,幼兔的死亡现象更为严重,影响了养兔业的发展。幼兔由于断奶,离开了母体独立生活,环境条件发生了很大变化,加之幼兔生长发育快,抗病力差,很容易患病死亡。笔者认为,要提高幼兔成活率,使幼兔全活全壮,必须从以下几方面着手。1　适时配种,合理断奶幼兔成活率的高低,与公母兔配种早晚有很大关系,配种过早容易引起先天不足,配种过晚增加饲养成本。对初产母兔来讲要做到适时配种,一般应在7～8月龄,体重2.5ｋｇ以上,公兔9～10月龄,体重3ｋｇ以上方可配种,经产母兔掌…     

家兔肌肉组织表达外源性生长激素释放因子对增重的影响

用 Wicks法提取 pc DNA- GRF(1～ 32 )质粒并用 DNA Cacu L ator定量 ,同时制备原生质体。将 5 4只家兔随机分为 9组 ,分别注射质粒 pc DNA- GRF(1～ 32 ) 0 .4(用布比卡因处理 )、0 .4(含 10 %甘油 )、0 .4(含 2 5 %蔗糖 )、0 .2、0 .4、0 .6、0 .8mg及空质粒 0 .1mg和原生质体 1m L( ～ 组 )。分别于注射后 0、3、8、14、19、2 4、31d称重 ;于注射后 0、3、8、19、31d采血并分离血清 ,测定血清中 GH浓度 ,用 t检验进行统计学分析。结果表明 ,布比卡因处理组注射后 3d内GH浓度升高 6 5 %(P<0 .0 1) ,平均日增重 2 9g(P<0 .0 5 ) ;注射 0 .8mg组 31d平均日增重较对照组多 34 .6 2 %;注射原生质体组 31d平均日增重较对照组多 40 .5 7%(P<0 .0 5 )。 31d后将家兔屠宰 ,取注射部位肌肉提取 DNA和总RNA,用 PCR和 RT- PCR方法分别检测到了 GRF在肌肉中的存在和表达 ;用 EL ISA方法没能检测到血清中的 GRF抗体。     

兔超数排卵效果及早期胚胎体外发育的研究

实验分30、40、50和60 IU PMSG和150 IU hCG 4组超数排卵处理,对卵巢进行组织学观察,获得胚胎进行体外培养,研究其发育形态学变化。结果表明:注射30 IU PMSG超排效果较好,平均回收卵(18.4±11.1)枚,回收率89.7%;4种剂量显著(P<0.05)影响充血卵泡中颗粒细胞层数和直径,对原始卵泡没有显著影响(P>0.05),对次级卵泡的颗粒细胞层厚、颗粒细胞层数和颗粒细胞直径有极影响显著(P<0.01);30 IU组初级卵泡中颗粒细胞直径显著(P<0.05)小于40 IU和60 IU组;实验所采用的培养体系可以使胚胎正常发育至孵化囊胚,胚胎发育速度与在体内相近,受精后62～74 h开始进入囊胚期,受精后86～98 h囊胚开始孵化,15 h所有存活胚胎全部进入孵化胚阶段,囊胚发育率85.4%,孵化率70.7%。     

Cell Cycle Stage Analysis of Rabbit Foetal Fibroblasts and Cumulus Cells

Synchronization of the cell cycle stages in G0/G1 phase is one of the key factors determining the success of nuclear transplantation. Serum deprivation, contact inhibition and chemical inhibitors are widely used methods for this purpose. In this study, cell cycle stages of foetal fibroblasts and cumulus cells were determined using flow cytometry [fluorescence-activated cell scan (FACS)]. Foetal fibroblasts (in vitro cultured for 72-120 h) and fresh cumulus cells were analysed in Experiment 1. Fifty to 55% proliferating fibroblasts remained in G0/G1 phase compared with 78% in confluent culture (p <0.05). In contrast to foetal fibroblasts, fresh cumulus cells maintained 90% of the population in the G0/G1 stage. When serum was retrieved from the proliferating fibroblasts from day 1 to day 5 (Experiment 2), proportions of G0/G1 cells increased from the initial ratio of 53 to 87% at day 4 of starvation, which was significantly higher than the non-starved proliferating cells (p <0.05). In Experiment 3, fibroblasts were treated with aphidicolin (0.1 microg/ml, 6 h), demicolcine (0.5 microg/ml, 10 h), or a combination of these two chemicals to synchronize the cell cycle stages. Surprisingly, no differences or significantly lower in the proportions of G0/G1)phase cells were detected (25-50%) compared with the uncontrolled growing cells (53%). These results suggested that fresh cumulus cells rest their cell cycle in G0/G1 stage. Serum deprivation became effective in the first 24 h and reached the highest proportions during days 4-5 after deprivation. Chemical synchronization of the cell cycle stage of rabbit foetal fibroblasts to G0/G1 phase appeared less effective compared to serum deprivation.     

Human Foetal Sacral Length Measurement for the Assessment of Foetal Growth and Development by Ultrasonography and Dissection

This study investigated the value of prenatal ultrasonographic measurements of sacrum as a predictor of in utero development and gestational age (GA), and to make a comparison between the data obtained by ultrasonography and dissection. A prospective cross-sectional study of ultrasonography was conducted in 186 pregnant women with uneventful single pregnancies. GA ranged from 14 to 40 weeks, and the relationships of sacrum length (SL) with GA, femur length (FL), biparietal diameter (BPD), head circumference (HC) and abdominal circumference (AC) were evaluated. In addition, the sacral bones of 101 spontaneously aborted foetuses aged from 13 to 39 weeks were dissected and measured. The relationship of the results with GA was investigated. There was a linear relationship between the ultrasonographic measurements of the SL and the GA (R2 = 0.93, P < 0.001), the FL (R2 = 0.93, P < 0.001), the BPD (R2 = 0.93, P < 0.001), the HC (R2 = 0.92, P < 0.001) and the AC (R2 = 0.90, P < 0.001). The rate of increase of SL was significantly higher before 28 weeks of gestation than in later pregnancy, with a correlation coefficient between SL and GA of 0.96 and 0.88, respectively. The SL measurements obtained by dissection were similar to those of ultrasonography. There was a linear relationship between the SL and the GA (R2 = 0.96, P < 0.001) and the correlation coefficients between SL and GA were 0.97 before 28 weeks of gestation, and 0.94 in later weeks. In conclusion, this study demonstrates a high correlation between the SL, GA and other standard measurements of foetal growth, and suggests that SL measurement is a valuable predictor of GA in the foetuses with normal growth.     

Anomalous Pregnancies during Late Embryonic/Early Foetal Period in High Producing Dairy Cows

This study analyses anomalous cases of gestation ending in pregnancy loss during the early foetal period and their effect on progesterone and plasma pregnancy-associated glycoprotein-1 (PAG-1) concentrations. Data derived from a large-scale ultrasound pregnancy diagnosis programme in high producing dairy cows. Over a 3-year period (2004–2007), a very low incidence (0.5%: 15 of 3094) of anomalous pregnancies was recorded. The results revealed that the following anomalies were detected on days 35–41 of gestation in cows carrying singletons with one single corpus luteum: embryo death in eight cows (0.3%); and embryo in the uterine horn contralateral to the corpus luteum in seven cows (0.2%). All these animals suffered pregnancy loss during the early foetal period. In cows carrying dead embryos, no signs of conceptus degeneration were observed on pregnancy diagnosis. Amnion size (approximately 25 mm diameter) and uterine horn fluid contents were estimated to be similar to those of the normal pregnant cows in this period. In the contralateral gestations, live embryos were observed in all ultrasound checks before pregnancy loss. Uterine fluid contents increased in the two cows in which gestation continued for more than a week. In the cases of embryo death but not in those of contralateral gestation, a drop in PAG-1 levels was noted prior to pregnancy loss. Two cows carrying dead embryos increased with time allantoic fluid contents. The PAG-1 values increased with time in one cow bearing a dead embryo (from 2.31 to 6.79 ng/ml) and in two of the contralateral gestations (from 1.66 to 2.33 ng/ml and from 0.39 to 6.79 ng/ml, respectively). Results of this study indicate that the foetal membranes continue to undergo some activity following embryo death, and that contralateral pregnancy may determine failure of the gestation process.     

日粮中添加巴尔麦氏对肉兔生长的影响

选择120只体重、日龄相近的新西兰白兔,随机分成四组,对照组日粮中不添加巴尔麦氏,试验Ⅰ组、试验Ⅱ组、试验Ⅲ组日粮中分别添加0.08%、0.10%、0.12%巴尔麦氏.结果表明:生长肉兔的日粮中添加巴尔麦氏能显著提高肉兔的日增重和饲料转化率,试验Ⅱ组、试验Ⅲ的日增重和料重比与对照组均存在显著(P＜0.05)或极显著的差异(P＜0.01);各组之间屠宰率无显著差异(P＞0.05);各试验组与对照组相比,发病死亡率明显下降;与对照组相比较,试验Ⅰ、试验Ⅱ、试验Ⅲ的经济效益分别提高了1.77%、13.21%、16.73%.巴尔麦氏可明显提高养兔效益,可进一步研究推广应用.     

产箱环境对母貂母性行为和仔貂生长发育的影响

试验探讨了产箱环境对母貂母性行为和仔貂存活、生长、发育的影响。4种新型产箱类型有A、AB、AC、AD,B型为传统产箱。通过母貂的做窝行为和对5日龄仔貂的取回试验判断产箱环境对母貂母性行为的影响,通过出生重、出生个数、仔貂死亡率、平均体重、体表温度来判断产箱环境对仔貂存活、生长的影响。结果表明,仔貂的出生重和出生个数不受产箱环境的影响;AC型产箱能够增强母貂的母性,提高1~14日龄仔貂的存活率和平均体重。新型产箱在保温性能和产仔保活方面都优于传统产箱。     

日粮不同营养水平对母猪妊娠早期胚胎存活的影响

试验以63头长白-大白杂交初产母猪为试验动物,研究不同营养水平对母猪妊娠早期繁殖性能的影响。将配种后母猪随机分到3个营养水平组(高、中、低)中,各营养水平通过每天供给2、1.2和0.6倍维持需要的饲粮,分别在妊娠12、25和35d将母猪称重、屠宰。结果表明:各水平组母猪妊娠12、25和35d的母体总增重和净增重有极显著(P<0.01)差异。中水平妊娠25d的子宫及内容物重量和两侧子宫角长度均显著(P<0.05)高于高水平和低水平;中水平妊娠35d的子宫及内容物重量和右侧子宫角长度显著(P<0.05)高于高水平。中水平妊娠12 d的总活胚数显著(P<0.05)高于高水平。中水平妊娠12、25和35d的胚胎存活率显(著P<0.05)高于高水平;中水平妊娠25d和35d的胚胎存活率显著(P<0.05)高于低水平。中水平妊娠35 d的活胚重显著(P<0.05)高于高水平,极显著(P<0.01)高于低水平。以上试验表明,在妊娠35d内给母猪饲喂1.2倍维持需要能使子宫发育更良好,并具有较高的胚胎存活率,而高水平饲喂和严重限饲均会导致母猪妊娠早期的胚胎存活率降低。     

福建兔生长模型研究

对693只福建兔黄毛和黑毛2个品系体重进行Logistic曲线模型拟合。结果表明:福建兔黄毛品系公母兔及黑毛品系公母兔的生长模型分别为:y=1(/1/3 679+0.007 1*0.973 1x),y=1(/1/4 197+0.006 6*0.977 8x),y=1/(1/2 830+0.003 2*0.974 3x),y=1(/1/3 290+0.003 5*0.976 7x);2个品系实际生长曲线与Logistic生长模型的拟合度均在0.925以上(P<0.01),其中以福建兔黄毛品系公兔生长模型的拟合度最高(R=0.959);福建兔黄毛品系公兔的生长拐点在120日龄,体重为1 848.2 g,成熟体重为3 696.4 g;福建兔黄毛品系母兔的生长拐点在148日龄,体重为2 099.7 g,成熟体重为4 199.4 g;福建兔黑毛品系公兔的生长拐点在89日龄,体重为1 413.7 g,成熟体重为2 827.4 g;福建兔黑毛品系母兔的生长拐点在104日龄,体重为1 651.8 g,成熟体重为3 303.6 g。     

如何提高仔幼兔成活率

兔是仅次于小鼠最常用的实验动物 ,它广泛用于各种科学研究。仔幼兔阶段易发生感染性和非感染性疾病 ,是兔的一生中最难饲养的时期 ,这是育成兔成活率低的主要原因之一。为了提高仔幼兔的成活率 ,只有采取综合措施 ,抓好仔幼兔饲养中的每一个环节 ,才能提高仔幼兔的成活率。1　搞好环境卫生每天清扫兔舍 ,打扫粪便 ,清洗饲具 ,对兔舍及饲具要定期消毒 ,巢箱要清洗暴晒 ,垫草要干燥清洁 ,没有异味 ,经常通风换气 ,确保空气新鲜。2　加强母兔饲养管理首先要抓好母兔妊娠期与哺乳期的饲养管理。母兔在妊娠期应给予营养丰富 ,无污染 ,含有多种维…     

影响体外培养兔胚发育和兔类ES细胞分离的若干因素

本试验系统地比较了影响兔囊胚体外培养和免类ＥＳ细胞系分离的几个主要因素。结果表明，３种不同糖浓度（４．５，１．０，０．２ｇ／Ｌ）在４８ｈ内对胚胎贴壁均无显著影响。在高糖ＤＭＥＭ中，早期胚胎内细胞团（ｉｎｎｅｒｃｅｌｌｍａｓｓ，ＩＣＭ）增殖速度最快，分化也快；超低糖组，ＩＣＭ增殖缓慢，分化出现时间较晚；低糖组，ＩＣＭ既能保持较快的增殖速度，又能维持较长时间的未分化状。高糖组和低糖组的ＥＳ细胞样集落的传代能力相似，可达６～７代，超低糖组中不超过２代。胰岛素能促进ＩＣＭ的增殖，并可提高传代过程中ＥＳ细胞样克隆的形成率。在小鼠胚胎原代成纤维细胞（ＭＥＦ）和一种经白血病抑制因子转化了的小鼠成纤维细胞系（ＳＮＬ）上，ＩＣＭ都能维持较快的增殖速度，在家兔胚胎原代成纤维细胞（ＲＥＦ）中ＩＣＭ增殖较慢，无饲养细胞条件下，ＩＣＭ存活率低，生长状况不佳。传代能力，ＲＥＦ要比ＭＥＦ和ＳＮＬ低，且主要形成上皮样集落。作者根据以上实验结果认为，用低糖ＤＭＥＭ为基本培养基，再加入胰岛素，在ＭＥＦ或ＳＮＬ上培养切割胚胎和连续传代的技术路线是较为可行的。     

不同类型肥育猪生长性能及胴体性状的研究

作者主要探讨不同类型猪在生长性能与肌肉品质的差异。挑选50 kg 左右的鄂西黑猪(脂肪型)、长大二元杂交猪(瘦肉型)、长♂×(野♂×鄂♀) ♀(中间型)三元杂交阉公猪各24头,饲养至100 kg左右屠宰,每个品种屠宰6头,进行生长性能、胴体性状与肉质性状的测定。研究结果表明,长大二元杂交猪的生长速度显著高于鄂西黑猪(P<0.05),而与长野鄂杂交猪差异不显著(P>0.05)。长大二元杂交猪的屠宰率、瘦肉率和眼肌面积显著高于鄂西黑猪和长野鄂杂交猪(P<0.05),而料重比、背膘厚显著低于鄂西黑猪(P<0.05)。长大二元杂交猪的肌肉pH2、滴水损失和剪切力显著高于鄂西黑猪,而肌肉评分显著低于鄂西黑猪(P<0.05),而长野鄂杂交猪的肉质与长大二元杂交猪和鄂西黑猪差异均不显著(P>0.05)。     

Effect of Fermented Corn Stalks on Growth Performance and the Growth Promotion Mechanism in Otter Rabbit

This experiment was conducted to research the growth promoting effects of fermented corn stalks with compound bacteria on otter rabbit. The daily feed of otter rabbit was based on fermented corn stalks (roughage ration composed mostly of fermented corn stalks). The growth performance, intestinal tract bacteria and the digestive enzyme activities of otter rabbit were studied. A total of 150 health otter rabbits, 9 weeks old, weighted about (1.90±0.14) kg, were allotted to 2 groups (control group and experimental group) for 10 days preliminary trial period and 30 days trial period. The results were as follows:Compared with control group, the average daily gain (ADG) increased by 14.60% (P<0.05) and F/G decreased by 10.50% (P<0.05) of the experimental group; In intestinal tract of otter rabbit, the number of E.coli were reduced by 46.13% (P<0.01), the number of Lactobacillus, Bifidobacteria and Bacillus increased by 30.64% (P<0.05), 29.27% (P>0.05) and 39.23% (P<0.01),respectively; The activities of protease, amylase, cellulose enzyme and glucanase were increased by 23.20%(P<0.05), 32.96% (P<0.05), 12.63% (P<0.01) and 21.09% (P<0.05), respectively. In conclusion, the fermented corn stalks could promote the growth and improve the intestinal tract ecological environment of the otter rabbit. The results established the theoretical foundation for fermented corn stalks feeding on otter rabbit.     

发酵玉米秸秆对獭兔生长性能的影响及其促生长机理的研究

试验旨在研究经复合菌剂发酵后的玉米秸秆粗饲料对獭兔的促生长效果。用以发酵玉米秸秆为主要粗饲料配制的日粮饲喂獭兔,从试兔生长性能、肠道菌群结构、消化酶活力的变化来揭示发酵玉米秸秆对獭兔生长的影响。选择体况良好,9周龄、体重（1.90±0.14） kg獭兔150只,将其分为对照组（饲喂常规基础日粮）和试验组（发酵玉米秸秆为主要粗饲料的日粮）,预试期10 d,正试期30 d。结果显示,与对照组相比,试验组獭兔平均日增重（ADG）提高了14.60%（P<0.05）,料重比（F/G）降低了10.50%（P<0.05）;盲肠内容物中大肠杆菌数量降低了46.13%（P<0.01）,乳酸菌、双歧杆菌、芽孢杆菌数量分别提高了30.64%（P<0.05）、29.27%（P>0.05）和39.23%（P<0.01）;盲肠中蛋白酶、淀粉酶、纤维素酶、葡聚糖酶活力较对照组分别提高了23.20%（P<0.05）、32.96%（P<0.05）和12.63%（P<0.01）、21.09%（P<0.05）。综合以上结果,发酵玉米秸秆可促进獭兔生长,改善肠道微生态环境。试验结果可为发酵玉米秸秆在獭兔中的应用提供理论基础。     

中草药添加剂对肉兔增重及成活率的影响

选取35日龄新西兰白兔30只随机分成6组,即对照组(A组)、试验组(B组、C组、D组、E组、F组)。利用本地丰富的中草药资源,筛选何首乌、蒲公英、辣蓼、杜仲、银杏叶、绞股蓝、松针、甘草、黄柏、车前草等十几种常见的中草药,按一定的比例配制成组方,然后分别以0.5%、1%、3%、5%、7%的比例加入试验组兔的基础日粮。试验结果表明,试验组与对照组相比增重提高,差异极显著(P<0.01),而试验组间差异不显著(P>0.05);各试验组与对照组相比,料重比分别下降19.10%、20.35%、25.11%、23.45%、23.16%;饲料利用率提高,经济效益极显著(P<0.01);发病率下降,成活率提高。