北京白鸡5—18日龄胚胎消化器官的显微结构

以组织学方法研究了孵化第５，９，１２，１８天鸡胚的胃、肠、肝、胰的显微结构，探讨了鸡胚胃、肠、肝、胰的形态发生。观察到腺胃粘膜深层的复管状腺比腺胃粘膜浅层和肌胃粘膜中的单管状腺结构复杂，肌胃的肌层比腺胃和肠管的肌层发达。诸如此类，器官中结构较复杂或较发达的部分需要较长的发育时间，往往发育较早；复腺的发育中先有腺管然后有腺管分支和腺泡；吞食蛋白羊水对消化器官的发育具有重要影响     

Histological evaluation of immune organs in chicken embryos inoculated with Marek's disease virus and lymphokines

The aim of the present study was to evaluate the presence of lymphocytes and granulocytes in different stages of embryonic development and on the first posthatching day. The lymphocytes present in the bursa of Fabricius and thymus were evaluated by histological analysis of the yolk sac, bursa of Fabricius, thymus, liver and bone marrow of 100 chicken embryos divided into groups and treated with: (I) Marek's disease vaccine as viral antigen, (II) Marek's disease vaccine plus lymphokines, (III) lymphokines, and (IV) vaccine diluent. Group V was not treated. Samples were taken on days 14, 17 and 20 of incubation and on the first posthatching day. An increase in the number of epithelial matrix as precursors of lymphoid follicles was observed in the bursa of Fabricius of embryos inoculated with lymphokines compared to embryos in all the other groups (p < 0.05). In addition, a higher amount of granulocytes was found in the yolk sac and liver of embryos inoculated with lymphokines than in the embryos of all other groups (p < 0.05). In the bone marrow, no significant difference was observed among the treated groups concerning the amount of granulocytes. The results suggest that administration of antigens or protein molecules at an early stage of embryonic development increases the presence of granulocytes in the liver and granulopoiesis in the yolk sac, and also increases the number of epithelial matrixs in the bursa of Fabricius.     

Non-ventilation during early incubation in combination with dexamethasone administration during late incubation: 1. Effects on physiological hormone levels, incubation duration and hatching events

This study investigated the effect of non-ventilation of the incubator during the first 10 days of incubation and its combination with dexamethasone administration at day 16 or 18 of incubation on hatching parameters and embryo and post-hatch chick juvenile physiology. A total of 2400 hatching eggs produced by Cobb broiler breeders were used for the study. Blood samples were collected at day 18 of incubation, at internal pipping stage (IP), at the end of hatch (day-old chick) and at 7-day-post-hatch for T(3), T(4) and corticosterone levels determination. From 448 to 506 h of incubation, the eggs were checked individually in the hatcher every 2h for pipping and hatching. The results indicate that non-ventilation during the first 10-day shortened incubation duration up to IP, external pipping (EP) and hatch, had no effect on hatchability and led to higher T(3) levels at IP but lower corticosterone levels at 7-day-post-hatch. The injection of dexamethasone at days 16 and 18 of incubation affected hatching and blood parameters in both the ventilated and non-ventilated embryos differentially and the effect was dependent on the age of the embryo. Dexamethasone increased T(3) levels and T(3)/T(4) ratios but the effect was greater with early non-ventilation of eggs. Dexamethasone decreased hatchability but the effect was greater when injected at day 16 and especially in ventilated embryos. The effects of incubation protocols and dexamethasone treatments during incubation were still apparent in the hatched chicks until 7 days of age. The changes in T(3), T(4) and corticosterone levels observed in response to the early incubation conditions and late dexamethasone treatments in this study suggest that incubator ventilation or non-ventilation may influence the hypothalamic-pituitary-adrenal axis (HPA) regulation of stress levels (in terms of plasma corticosterone levels) and thyroid function in the embryo with impact on incubation duration, hatching events and early post-hatch life of the chick. Our results also suggest that some stages of development are more sensitive to dexamethasone administration as effects can be influenced by early incubation protocols.     

不同厂家胰酶制备鸡胚成纤维细胞对比试验

本试验用半胚法制备鸡胚成纤维细胞,用胰酶对SPF鸡胚进行消化培养,并观察所得细胞的生长情况。在相同条件下设立两个对照组,观察胰酶在细胞制备过程中对试验的影响,并比较不同厂家(Gibco和Difco)生产的胰酶在相同条件下对鸡胚消化情况及所得细胞生长情况的影响。     

An Avian Model for Comparative Studies of Insulin Teratogenicity

This study was designed to explore the effects of purified insulin during early stages of chick embryo development, and to search for variations between different molecular structures of the hormone. Chicken embryos were treated in ovo with a single dose of insulin (porcine or bovine), in only one stage of development between day 0 and day 9. Two susceptible periods were found. The earliest period (day 0 to day 3), characterized by abnormalities in the caudal vertebrae and a high mortality rate, was followed by a period with a different set of malformations, a syndrome classified as achondroplasia. The rate of achondro-plastic embryos was significantly higher with porcine rather than with bovine insulin. Paradoxically, insulin at physiological doses has stimulatory effects in growth and development but, in contrast, has inhibitory effects at higher doses. The precise signalling cascade of events in the target cells is still unclear. The possible interpretations of our results are discussed. The similarity between the insulin-induced abnormalities in the chicken embryos and the caudal regression syndrome, the most common malformation found in infants of diabetic women, suggests a common mechanism. This circumstance offers the chicken embryos as an excellent in vivo model for research on the mechanism of action of insulin during normal and abnormal development.     

Effect of species-specific sound stimulation on the development and hatching of broiler chicks

1. Previous research has reported that chicken embryos develop a functionary auditory system during incubation and that prenatal sound may play an important role in embryo development and alter the hatch time. In this study the effects of prenatal auditory stimulation on hatch process, hatch performance, the development of embryo and blood parameters were investigated.

2. Four batches of Ross 308 broiler breeder eggs were incubated either in control or in sound-stimulated groups. The sound-stimulated embryos were exposed to a discontinuous sound of species-specific calls by means of a speaker at 72 dB for 16 h a day: maternal calls from d 10 to d 19 of incubation time and embryo/chick calls from d 19 until hatching. The species-specific sound was excluded from the control group.

3. The onset of hatch was delayed in the sound-stimulated group compared to the controls. This was also supported by comparison of the exact hatching time of individual focal chicks within the two groups. However, the sound-stimulated embryos had a lower hatchability than the control group, mainly due to significantly increased numbers of late deaths.

4. The embryos exhibited a similar growth pattern between the sound-stimulated group and the control group. Although sound exposure decreased body weight at d 16, no consistent effect of sound on body weight at incubation stage was observed. Species-specific sound stimulation also had no impact on chick quality, blood values and plasma corticosterone concentrations during hatch.     

InducciÓn Experimental á Malformaciones por Instilacion de Etanol en Huevos Embrionados de Polio (Gallus gallus)

The teratogenic effect of alcohol on chick embryos has been confirmed by many investigators. However, how this occurs is unknown. The aim of this study was to establish a teratogenic pattern of alcohol effects, on the first stages of development in avians. Fertilized eggs were infused through the air space of the shell on day 0, with ethanol in concentrations of 20%, 40% and 60%. The control group was infused with 0.1 ml of NaCl at 0.9%. At a second stage, the eggs were treated on the 4th day of incubation, using the same method. In both groups the eggs were removed on the 11th day of incubation. The teratological manifestations that appeared more frequently were evisceration, haemorrhagic embryos, oedema, cranial deformities, lack of eyes, and umbilical hernia, showing every embryo a clear reduction in size and body weight.     

Strain differences in whole-body protein turnover in the chicken embryo.

1. Whether or not there is a strain difference in embryonic whole-body protein turnover rates was tested using the chicken embryos of Rhode Island Red carrying a sex-linked dwarf gene (dwarf), White Leghorn (layer), and White Cornish X White Plymouth Rock (broiler) strains on day 12 of incubation. 2. Whole-body protein synthesis was estimated by injecting L-[15N]-phenylalanine either intraperitoneally or intravenously on day 12 of incubation in order to investigate the effect of the route of isotope administration. The results showed that the values for fractional and absolute synthesis rates were approximately 13% higher by intravenous injection than by intraperitoneal injection. 3. Whole-body protein turnover, both in terms of fractional and absolute rates, was significantly faster in dwarf than in broiler embryos, with intermediate values in layer embryos, although no growth differences were observed on day 12. 4. Difference in egg weight, measured before incubation, did not affect protein turnover. 5. It was concluded that the strain difference manifested in whole-body protein turnover of the chicken embryo would probably be a reflection of differences in genetic background.     

A simplified biopsy method for precompacted mouse embryos: a technical report

This article presents a new, simple and rapid embryo biopsy method. The blastomere for genetic analysis can be separated from a precompacted mouse embryo after a partial zona digestion with the use of a holding pipette. For the micromanipulation only two microcapillaries and micromanipulators are needed. The development of the biopsied embryos was studied during in vitro culture and in utero following embryo transfer. There was no significant difference between the treated and the control groups in the ratio of embryos that developed to the blastocyst stage, although the biopsied embryos were delayed in their development because they contained significantly fewer cells compared to the control ones at the same stage. Although there was no difference in the ratio of implantation, the development of the biopsied embryos in utero was also delayed 12-24 hours on the 9th day of pregnancy. No difference in development was visible from the 13th day of pregnancy. Statistically, no differences were found in the developmental ratio (number of developed fetuses/transferred embryos) of the control and treated embryos during gastrulation (9th day of pregnancy), at the beginning of organogenesis (13th day of pregnancy) and before birth (19th day of pregnancy). The embryo biopsy method presented here can be a new and useful tool for preimplantation genetic diagnosis.     

用异源蛋白和蛋壳体外培养鹌鹑胚胎的研究

将50个鹌鹑胚胎在鸡蛋壳中用鸡稀蛋白培养,对种蛋产出体外阶段裸黄状态的鹌鹑胚胎进行培养的方法进行了探讨。1～2.5d、2.5～14d和15～17d胚胎培养温度分别是38.0℃、37.8℃和37.5℃,相对湿度分别是60%、55%和70%,1～14d每小时翻蛋1次,翻蛋角度1～2.5d为90°,2.5～14d为50°,15d后静止落盘。2.5d和15d胚胎存活率以及孵化率分别为92%、78%和28%。结果表明裸黄状态的鹌鹑胚胎不排斥鸡稀蛋白,用鸡稀蛋白培养鹌鹑胚胎可行。     

Study on Development of Broiler Liver Lipid Droplet during Embryonic Period

This study was aimed to explore the developmental change of lipid droplet in liver of chicken embryos.120 fertilized eggs were incubated, and 6 embryos were selected randomly every day and their livers were removed for measuring the formation and development of lipid droplets from E7 to E21 during the incubation.The methods of frozen section and Sudan Ⅲ staining were used. The results showed that:①Lipid droplets emerged early on the 9th day of chicken embryos incubation (E9). The quantities and sizes of lipid droplets became more and larger with the increasing of chicken embryos age. ②Quantities of lipid droplets in every hepatic lobule decreased from central veins to the margin of hepatic lobule along hepatic cords before E18, while more lipid droplets distributed at the margin of the liver than that in the center of liver after E18. ③The quantities and sizes of hepatic lipid droplets were significant difference during the three stage of E9-E14, E15-E17 and E18-E21 (P<0.05). The average sizes of hepatic lipid droplets were 3.2, 5.7 and 10.8 μm, respectively, and their average numbers were 67,327 and 397 n/mm², respectively. In conclusion, the quantities and sizes of hepatic lipid droplets became more and larger with the increasing of chicken embryos age.     

肉鸡鸡胚肝脏中脂滴的发育研究

为了探索鸡胚肝脏脂滴的发育规律,选取120枚受精蛋,分别在孵化的第7~21天（E7~E21）每天随机选取6枚蛋,收集鸡胚,采集鸡胚肝脏,采用冰冻切片、苏丹Ⅲ染色观察鸡胚肝脏脂滴的形成和发育特点。结果发现：①鸡胚发育到E9胚龄,肝细胞内开始出现脂滴,且随着胚龄增加,脂滴的数量不断增多,脂滴的大小不断增大;②E18胚龄以前,肝脏脂滴的分布从中央静脉开始沿肝索到肝小叶边缘数量逐渐减少,E18胚龄以后,肝脏边缘脂滴数量较肝脏中央的多;③肝脏脂滴的发育分为E9~E14、E15~E17和E18~E21 3个阶段,而且后一个阶段脂滴的数量和体积均显著大于前一个阶段（P<0.05）,脂滴的平均大小在E9~E14、E15~E17和E18~E21 3个阶段分别为3.2、5.7和10.8 μm,平均数量分别为67、327、397个/mm²。以上结果表明,随着鸡胚的发育,肝细胞内脂滴数量增加、体积变大。     

OPS玻璃化冷冻对小鼠四倍体胚胎体外发育的影响

为探究开放式拉长细管(OPS)玻璃化冷冻对四倍体胚胎发育的影响,本实验利用2-细胞胚胎电融合法制备四倍体胚胎,再对四倍体胚胎进行OPS玻璃化冷冻,分别观察记录二倍体胚胎、四倍体胚胎以及冷冻解冻后四倍体胚胎的发育情况。结果表明:2-细胞胚胎电融合效率为96.1%;二倍体胚胎组与电融合后四倍体胚胎组的囊胚率和孵化囊胚率差异不显著;冷冻解冻后四倍体胚胎的囊胚率(100%)与四倍体新鲜组(93.3%)差异不显著,其孵化囊胚率(72.3%)较新鲜组(64.9%)显著增高(P<0.05);四倍体冷冻解冻组的囊胚细胞数(31.96)与新鲜组(32.54)无显著差异;冷冻解冻后的四倍体早期囊胚进行体外培养时其发育速度比对照组更快。可见,冷冻对小鼠四倍体胚胎的囊胚率和囊胚细胞数均无显著影响,但孵化囊胚率显著提高,且OPS玻璃化冷冻后使四倍体胚胎的发育速度更快。     

Calcium homeostasis and intact plasma parathyroid hormone during exercise and training in young Standardbred horses

Physical exercise is known to affect calcium homeostasis in horses, but there is little information on the hormonal regulation of calcium metabolism during exercise. In order to evaluate the effects of exercise and training on calcium homeostasis and intact plasma parathyroid hormone, 7 untrained Standardbred horses were studied in a 6 week training programme. These horses were accustomed to running on the treadmill 3 weeks before onset of training and were exercised on a high-speed treadmill with an initial incremental standardised exercise test (SET 1: 6 incremental steps of 5 min duration each; first step 5 m/s, increase 1 m/s). SET 1 was followed by a lactate-guided training programme (6 weeks in total) with 2 types of exercise in alternating order with a day of rest after each work day: high-speed exercise (HSE) of 15 min duration, starting at VLa4, continuous increase in speed every 60 s by 0.3 m/s (14 incremental steps); and low-speed exercise (LSE) at a constant velocity at VLa2.5, duration approximately 60-90 min. The whole training programme consisted of 8 HSE and 8 LSE sessions. HSE and LSE were calculated to require the same energy expenditure. A final SET (SET 2) finished the training programme. Blood samples for lactate, plasma total calcium [Ca], blood ionised calcium [Ca2+], blood pH, plasma inorganic phosphorus [P(i)] and plasma intact parathyroid hormone [PTH] were collected before, during and after SETs 1 and 2, before and after the first and eighth HSE and LSE. During SETs 1 and 2, HSEs 1 and 8 there was a decrease in ionised Ca2+ and pH and a rise in lactate, intact PTH and P(i). LSEs 1 and 8 resulted in an increase in pH, whereas lactate, ionised Ca2+, total Ca, P(i) and intact PTH were not affected. No changes in calcium metabolism were detected during training. Results of this study suggest that intact PTH is a mediator in counter-regulation of exercise-induced hypocalcaemia.     

Importance of sub-embryonic fluid and albumen in the embryo's response to turning of the egg during incubation

1. The effects of removal of sub-embryonic fluid and albumen on the development of the fowl embryo were investigated. 2. A deficiency of sub-embryonic fluid on day 7 of incubation resulted in a reduction in the volume of the yolk sac and of allantoic fluid, and a reduction in the mass of the embryo later in incubation. 3. A deficiency of albumen on day 3 of incubation led to a reduction in allantoic fluid and embryo mass after day 12 incubation. 4. The results suggest that the physiology of embryos in unturned eggs is better modelled by eggs deprived of albumen than by eggs deprived of sub-embryonic fluid.     

鸡胚蛋重比作为评价传染性支气管炎病毒致侏儒化指标的研究

在鸡胚上接种鸡传染性支气管病毒（M41、H120、HN99株）后6 d内,每天称量胚体和各自种蛋的重量,计算胚体/种蛋重量的比值（EE值）。EE值与未接种病毒的对照组鸡胚相比,计算出最小感染量,EE指数通过接种过IBV的鸡胚EE值和对照组EE值相比计算出来。结果表明,在接种M41株和HN99株后第4天EE值与对照组差异显著,在接种H120株后第5天EE值与对照组差异显著,可初步判定是被传染性支气管炎病毒感染,这种方法可更快更有效的观察胚体损伤程度,尤其适用于需经传代才能看到矮小化现象的野毒株。     

用数学模型拟合鸡胚胸腺生长发育的研究

观察成都白羽鸡不同胚龄的鸡胚胸腺,结果,鸡胚胸腺在受精卵孵化到第9天时才开始形成.14胚龄时,胸腺长度为20胚龄的50%.18胚龄时,胸腺重量为20胚龄的50%.鸡胚胸腺长度与胚龄关系呈逻辑斯蒂S曲线生长,胸腺的重量呈指数增长模型.两者与胚体的关系分别呈对数函数和幂函数增长.建议采用逻辑斯蒂S曲线生长和指数增长模型分别拟合胸腺的长度、重量与胚龄的关系.     

Analysis of chicken embryonic development after removal of blastodermal cells for sexing

1. The present study evaluated developmental characteristics in the chick embryo throughout incubation following cell removal from the freshly laid egg. 2. Between 10 and a few hundred cells of the blastoderm were removed for sex diagnosis. Incubation of the treated embryos was then continued in an open egg shell culture system. 3. Cell recovery from different regions within the blastoderm was performed. 4. The experiments presented here demonstrate the persistence of the developmental potential of chicken embryos in an in ovo culture system after removal of different numbers of cells from the germinal disc prior to incubation. 5. No deviations in developmental characteristics were recorded when compared to untreated control cultures. 6. No detrimental effects of double cell biopsies could be observed. 7. A similar number of chicks developed to hatch regardless of the location of manipulation within the blastoderm.     

Inhibition of in vitro lymphocyte blastogenesis by chicken alpha-fetoprotein

Chicken alpha-fetoprotein (ch-AFP), purified from fetal chicken serum and embryo extracts, respectively, was examined for its immunomodulatory effect in vitro. Significant (P less than 0.05) suppression of the allogeneic mixed lymphocyte reaction (MLR) was observed, when these preparations were added to one-way mixed lymphocyte cultures (MLC) in quantities of 62.5-1000 micrograms/ml. Suppression of the MLR was depending on the presence of ch-AFP for at least 16 h after initiation of the MLC, suggesting that this fetal protein was acting mainly in the early phase of lymphoblastogenesis. Serum of chicken embryos (12th and 15th day of incubation), day-old chickens, and of 10-week-old chickens of four different inbred lines were also found to exert suppression of the MLR. From these data, it is hypothesized that ch-AFP plays an immunoregulatory role by maintaining a certain stage of self tolerance during differentiation of the avian immune system.