鸡嗉囊组织结构及其淋巴组织分布的观察

本研究旨在对鸡嗉囊组织学形态及其淋巴组织的分布进行观察并与食管进行比较。选用27日龄海兰白鸡,无菌操作分离嗉囊及食管,制作冰冻切片,进行常规HE染色。结果显示,鸡嗉囊黏膜上皮为复层扁平上皮,相比于食管,角质化明显,黏膜皱襞数量更多,伸缩性大;同食管相似,嗉囊固有层中分布着大量的食管腺,但分布不均一,由腺细胞围成的管泡状腺直接开口于黏膜上皮,分泌大量的黏液;另外发现,在皱襞和隐窝的固有层中,大量淋巴细胞密集聚在黏液腺周围,甚至突入腺体内,从而使黏液腺上皮转化为淋巴上皮。结果显示,嗉囊在对摄入食物的贮存和浸润起着非常重要的作用,同时嗉囊位于消化道上段,其中的淋巴组织将对刚刚进入消化道的病原微生物起着重要的免疫防御作用。     

鸡胚法氏囊组织发育的电镜和组织学比较观察

本实验通过对孵化至１２～２１ 日龄的鸡胚法氏囊进行组织学和超微结构的连续性动态观察,较为详细的描述了早日龄鸡胚法氏囊分化发育过程中显微和超显微的变化过程。实验结果显示,尽管鸡胚发育到中、后期胚体内可能已经具有一定程度的免疫效应,但直至出壳前鸡胚法氏囊尚未形成较完整的能组织起有效体液免疫组织基础结构,其完善的形态结构需在后天环境中继续分化和发育。非炎性状态下法氏囊淋巴滤泡内自始至终出现异嗜性细胞,在法氏囊的分化发育中起着重要的组织改建作用。     

鸡胚免疫器官组织学发育过程观察

通过对孵化至12-21日龄鸡胚的免疫器官胸腺、脾及腔上囊进行组织学连续性观察，较为详细地描述了鸡胚免疫器官的组织发育过程。观察结果显示，胸腺的组织结构发育和形成较早，自12日龄起胸腺就已形成原始的胸腺小叶；虽然脾在12日龄时就已初具轮廓，但脾直到18日龄才开始隐约形成形态可辨的红髓和白髓；腔上囊淋巴滤泡自鸡胚发育到17日龄时即渐趋明显，但完整的滤泡皮质和髓质结构在出壳前仍然处于分化成熟阶段。     

鸡胚法氏囊的组织发育

本试验通过对孵化至１３－２１日龄的鸡胚法氏囊进行组织学的连续性动态观察,较为详细地描述了早日龄鸡胚法氏囊的组织学分化发育过程。实验结果显示,直至出壳胶鸡胚法氏囊尚未形成较完整的能组织起 体液免疫促进作用的组织基础结构,其完善的形态结构需在后天环境中分化和发育。     

锌缺乏对肉鸡淋巴组织器官发育的影响

锌缺乏对肉鸡淋巴组织器官发育的影响赵德明姜敬涛张日俊马毅新何诚方文军（中国农业大学，北京１０００９４）锌是维持人和动物正常生理功能和生物代谢所必需的重要微量元素之一［１］。近年来通过对锌代谢与疾病发生状况的研究表明，锌缺乏可以引起机体一系列代谢改变及...     

猪呼吸道淋巴组织发育的亚显微结构变化

应用组织学和电镜技术研究猪呼吸道发育过程中淋巴组织的变化。结果表明：扁桃体和咽部是呼吸道进入机体的第一个淋巴组织集中的部位，弥散淋巴组织在出生时就存在，淋巴小结不明显；20日龄时扁桃体中淋巴组织增生，淋巴小结清晰可见；120日龄淋巴小结数量增加，紧靠鳞状上皮密集排列，淋巴小结发育很好，并出现生发中心。扁桃体复层鳞状上皮中含有大量的上皮内淋巴细胞。气管叉是呼吸道进入机体的第二个淋巴组织集中的部位，出生时气管叉外膜中淋巴组织直接与气管支气管淋巴结相连，淋巴组织明显可见。20日龄时气管叉外膜中淋巴组织已分开，形成气管叉外膜密集的淋巴组织和气管支气管淋巴结两个部分。120日龄时气管叉处淋巴组织特别发达，黏膜上皮中上皮内淋巴细胞数量也显著增加。肺内气管和细支气管固有膜中均有较多的淋巴细胞，其中浆细胞数量增加，上皮中仍存在少量的上皮内淋巴细胞。本试验结果提示猪呼吸道是黏膜免疫较理想的诱导位点和效应位点，新生仔猪通过鼻腔免疫可提高呼吸道局部黏膜免疫力。     

鸡脾脏组织结构早期发育的动态观察

通过HE染色方法,观察了鸡不同生长发育阶段脾脏的组织发育过程和结构特征。研究发现,脾脏实质内的白髓与红髓在胚胎18日龄可准确辨认,4日龄雏鸡脾脏中形成明显可辨的动脉周围淋巴鞘和椭球周围淋巴鞘,14日龄雏鸡脾脏中观察到生发中心。随着日龄增长,脾脏各种特征结构不断发育成熟,并在35日龄时均趋于稳定。结果表明,鸡出壳后初期,脾脏免疫功能迅速增强,并在35日龄时达到成熟水平。     

鸡盲肠扁桃体组织结构早期发育的动态观察

本研究利用HE染色方法结合图像分析软件和数据统计软件,观察雏鸡不同生长发育阶段盲肠扁桃体的组织学发育过程和结构特征。结果显示:随着日龄的增长,盲肠扁桃体特征结构不断发育成熟,并在21日龄时基本达到成熟水平。21日龄时,盲肠扁桃体粘膜层中下部形成生发中心,其数目在35日龄时达到稳定。证实,鸡出壳后初期,盲肠扁桃体免疫功能迅速增强,并在35日龄时达到成熟水平。     

铜缺乏对肉鸡淋巴组织器官发育的影响

在为期７周的试验中，通过严格控制饲料和饮水中铜的添加水平，发现肉鸡铜缺乏时机体的生长发育受阻，体重和主要淋巴组织器官的重量减轻。病理组织切片中淋巴组织器官内淋巴细胞数量减少，少数样品中还观察到淋巴细胞和网状细胞的变性环死现象。     

B cell development in gut associated lymphoid tissues

B lymphocyte development can occur in a variety of anatomical sites. While typically considered to be a process that occurs in the bone marrow throughout life, it is becoming clear that gut associates sites of B cell development are critically important in many species of veterinary importance. Among these sites, the bursa of Fabricius in chickens and the ileal Peyer's patches of sheep are among the best studied. In these organs, it has become clear that many of the properties associated with B cell development in rodent and primate bone marrow do not apply. Thus while bone marrow B cell development typically involves an ongoing maturation of mature B cells from immature B lineage precursors that lack the expression of a surface immunoglobulin complex, gut associated lymphoid tissues (GALTs) may be colonized by a single wave of precursor cells during embryo development. Nonetheless, molecular analysis of the requirements for B lymphocyte development in GALTs reveals some striking parallels with requirements identified for B cell development in bone marrow. This article will discuss differences between B cell development in the bone marrow and GALTs and recent evidence emerging that yields insights into how these processes are regulated.     

Histological development of the small intestinal mucosa in the ovine fetus.

Histological changes in the small intestine of 85 ovine fetuses were studied, with particular reference to the mucosa. In 24-day-old fetuses the endoderm of the intestine consisted of a single layer of epithelium. By the 26th day the epithelium was flattened and stratified. The first evidence of rudimentary villus formation was noted in 39-day-old fetuses. Intestinal glands were first observed at 56 days. Other mucosal structures were present by 101 days. At birth the intestinal mucosa was fully mature.     

On epizootiology and control of lymphoid leukosis in chickens

Sera and organ extracts from ten different commercial stocks of layer chickens were examined for the presence of lymphoid leukosis (LL) viruses. Virus was recovered from 40.8% of the cockerels between three and six weeks of age. Their female hatch mates were examined at the age of 20 months. A mean of 11.3% of these laying hens was positive in the NP activation test. Lymphoid leukosis was successfully controlled in three inbred strains of White Leghorn chickens and in a commercial White Plymouth Rock line. All flocks were kept in a filtered air positive pressure (FAPP) house during the first two months of life and thereafter transferred to a conventional environment. The control method is based on three elements:

• —from an infected flock, hens are selected in whose eggs no avian lymphoid leukosis viruses can be detected by examination of pooled extracts of groups of embryos;

• —only eggs from hens that are shown not to shed congenitally virus in their eggs are used for the production of progeny. The offspring are reared in isolation until two months of age at which time the age-related resistance against tumour formation appears to be sufficiently developed;

• —the chickens are subsequently intramuscularly inoculated with lymphoid leukosis viruses of subgroups A and B and transferred to a conventional chicken house. The inoculated birds become persistently viremic and resist horizontal virus exposure and intramuscular challenge infections.

Horizontal virus transmission was observed to take place when virus-free non-vaccinated chickens were reared in isolation for two months and then exposed under field conditions.Efficiency of virus recovery was considerably improved when washed buffy coat cells were cocultivated with chick embryo fibroblasts or explant cultures were prepared from various tissues before testing with the NP activation test.     

Morphologic characterization of conjunctiva-associated lymphoid tissue in chickens.

Conjunctiva-associated lymphoid tissue (CALT) in the eyelids of chickens was studied by gross, histologic, and electron microscopic techniques. Structural features were characterized at 1 day of age and at posthatching week (PHW) 1, 2, 3, 4, 6, 8, 12, and 16. Beginning at PHW 1, prominent lymphoid nodules containing a heterogenous population of lymphocytes, lymphoblasts, and macrophages were first observed within conjunctival folds and fissures of the lower eyelid. Nodules contained germinal centers by PHW 2 and plasma cells by PHW 4. The epithelium associated with these nodules was flat, had short, irregular microvilli, contained intraepithelial lymphocytes, and lacked goblet cells. High endothelial venules were located at the base of lymphoid nodules and contained lymphocytes within and below the cuboidal endothelium. In the upper eyelid, CALT was morphologically similar to lymphoid tissue in the lower eyelid, but nodules were smaller and more random, lacked association with epithelial folds and fissures, and were clustered around the opening of the nasolacrimal duct. By PHW 12, CALT was characterized by basal germinal centers outlined by collagenous stroma, suprafollicular plasma cells, columnar epithelium with goblet cells, and fewer intraepithelial lymphocytes. On the basis of these features, CALT in chickens has morphologic characteristics similar to other components of the mucosal immune system and, therefore, may have a role in mucosal immunity.     

Histological intestinal alterations in chickens fed low protein diet

To demonstrate whether that hypotrophied histological alterations of intestinal villi and epithelial cells are observed in chickens fed low crude protein (CP) diet, 36 male chickens were allotted into 10%, 16% and 22% CP diets groups for 35 days. The 10% CP group showed a lower value of weight gain and feed efficiency than the other two CP groups (p < 0.05). On the relative weight of visceral organs, the 10% CP group showed a heavier gizzard than the 22% CP group, a heavier jejunum than the other two CP groups and a heavier value of ileum and caeca than the 22% CP group (p < 0.05). On the relative length of intestines, the 10% CP group showed a longer value of duodenum and caeca than the other two CP groups, a longer jejunum than the 16% CP group and a longer colon than the 22% CP group (p < 0.05). The villus height and villus area of all intestinal segments did not change in all groups. The duodenal cell areas and cell mitosis numbers tended to be lower in 10% CP group than in the other two protein groups, and the jejunal cell area and duodenal cell mitosis numbers were decreased in the 10% crude protein group (p < 0.05). In relation to the protuberated cells in the higher CP groups, the 10% CP group showed only faintly protuberated cells on the duodenal and jejunal villus apical surface. The ileal villi did not show specific alterations among each group. The chronic feeding of low CP diet induced a hypotrophied histological alteration. This suggests that the hypotrophied histological alterations can assess that the fed‐diet is not so well‐balanced diets, nutritionally.