B cell differentiation in the bursa of Fabricius and spleen of embryos and chicks immediately after hatching

Flow cytometric analysis and immunohistochemical observation were used to qualitatively and quantitatively clarify the nature of B cell differentiation in the bursa of Fabricius of chick embryos and to determine the timing of antibody class switching in chicken spleens based on positivity of IgM and IgG on and in the cells. In the bursa, the sIgM‐positive cell population formed from the 12^th to 15^th day of embryogenesis. The proportion of sIgM‐high expressing (sIgM^high) cells was lower among bursacytes than splenocytes of hatched chicks, suggesting that the sIgM^high bursacytes are to be released to peripheral sites. The proportion of sIgM^high cells was higher at 0 days old than at any other examined stage of development. Colonization of the spleen by B cells occurred between the 18^th day of embryogenesis and 0 days old. Antibody class switching was thought to start in the spleen between 1 and 2 weeks of age, because IgG‐positive cells were present in the spleen of 2‐week‐old chicks, but not 0‐day‐old or 1‐week‐old chicks.     

日粮中添加谷氨酰胺对肉仔鸡法氏囊发育的影响

谷氨酰胺（Glutamine，GLN）是体内组织间的氮前体穿梭工具，是快速增殖细胞（淋巴细胞和肠黏膜细胞）的主要能源物质，参与体内抗氧化剂-谷胱甘肽（GSH）的合成。具有维持肠道机能，提高机体免疫功能，改善酸碱平衡失调和提高机体对应激的适应等多种生理功能。GLN对机体免疫功能的作用已受到诸多学者关注：Ardawi等体外培养大鼠淋巴细胞发现，添加GLN可显著提高淋巴细胞的增殖；O’Riordain MG等证实，GLN能显著增强结肠、直肠切除病人体内T淋巴细胞DNA的合成。     

益生菌对肉鸡法氏囊发育及淋巴细胞增殖的影响

试验旨在研究不同种类的益生菌制剂对内鸡法氏囊发育以及淋巴细胞增殖的影响.选用雄性0日龄817肉鸡75只,随机分成5组.空白对照组饲喂基础日粮,试验组分别添加牧丁宝Ⅰ型、牧丁宝Ⅱ型、丁酸梭菌和益芪康,试验周期21 d.结果 显示:与对照组相比,益芪康、牧丁宝Ⅰ、牧丁宝Ⅱ和丁酸梭菌组的法氏囊增重分别提高13.61％、9.0...     

法氏囊超滤液提高仔猪日增重作用的研究

用法氏囊超滤液 (相对分子质量为 1 0 0 0以下 )以不同剂量分 2次间隔 2周免疫断乳仔猪 ,比较各试验组与对照组在日增重、料重比方面的差异。结果表明 :免疫组猪的饲料转化率、日增重显著高于对照组。此外 ,低剂量组 (1mg/头 ,2 5mg/头 )的日增重明显高于高剂量组(5mg/头 ,2 5mg/头 ) ,但料重比则明显低于高剂量组。免疫剂量为 2 5mg/头时 ,促进仔猪生长发育的效果最明显。     

GC02球虫病疫苗对鸡腔上囊发育的影响

将80只1日龄健康雏鸡随机分为GC02球虫病疫苗组（试验组）和对照组（n=40）。试验组鸡于7日龄和14日龄分别口服含8000个孢子化卵囊的GC02球虫病疫苗，对照组鸡口服生理盐水。于21、28、35和42日龄每组随机选取10只鸡，空腹称量体重，颈动、静脉放血致死，立即解剖取腔上囊称重并制作石蜡切片，光学显微镜下观察与拍照，研究了GC02球虫病疫苗对鸡腔上囊发育的影响。结果，试验组鸡腔上囊器官指数低于同日龄对照组，其中28-42日龄鸡的腔上囊器官指数显著或极显著低于对照组（P〈0．05或P〈0．01）。与对照组同日龄鸡相比，试验组鸡免疫GC02球虫病疫苗后，各日龄鸡腔上囊均表现出不同程度的病理组织学变化。试验组雏鸡腔上囊组织结构出现轻微损伤，GC02球虫病疫苗刺激了机体的免疫系统，增加了免疫效果。试验结果提示，GC02球虫病疫苗对雏鸡腔上囊发育有一定的抑制作用，对其组织结构有轻微损伤作用。     

Electron microscopy of bursa of Fabricius of chicks infected with a field strain of infectious bursal disease virus

Chicks were infected in the bursa with a field strain of infectious bursal disease virus. Inter- and intracellular edema, condensation and margination of nuclear chromatin, increased number of lysosomes in macrophages, and lymphocytolytic changes appeared earliest by 8 hours post infection. Inclusions containing spheroid to hexagonal virus particles were seen in the cytoplasm of the macrophages. Multiplying virus particles in crystalline arrays arranged either in single or in multiple clusters were seen in the cytoplasm of macrophages, lymphocytes and light stained reticular epithelial cells.     

Cryptosporidiosis of the bursa of Fabricius of chickens.

Light-microscope and electron-microscope studies of a coccidial organism found in the bursa of Fabricius from 3 chickens clearly established the parasite as belonging to the family Cryptosporiidae. Hyperplasia and heterophil infiltration were associated with the presence of organisms attached to the microvillus border of epithelial cells lining the plicae of the bursa of Fabricius. Although there were no clinical signs or gross lesions common to the 3 cases described, all had similar histologic lesions in the epithelium lining the bursa of Fabricius.     

Studies on the pathogenesis of Escherichia coli in the bursa of Fabricius (cloacal bursa) of the turkey.

Turkey poults were inoculated with avirulent or virulent strains of Escherichia coli by direct application to anal lips and were killed at postinoculation hours (PIH) 0.1, 2, 5, 10, 24, 48, 72, and 96. Bursae of Fabricius (cloacal bursae) were collected, cultured, and examined by light, fluorescent, and electron microscopy. The virulent strain of E coli was not recovered from the bursae after PIH 24, although the avirulent strain was recovered up to PIH 96. The E coli strains neither localized at nor associated with the bursal fold epithelium, passed through the follicular pad epithelium, nor caused cytopathologic changes in the lymphoid follicle. A mild catarrhal bursitis was observed at PIH 48 with the avirulent strain of E coli.     

雏鸭腔上囊的生长及组织发育

通过对1～49日龄雏鸭腔上囊绝对质量和生长指数测定以及组织学观察,探讨雏鸭腔上囊生长及组织发育规律。结果:随日龄增长,腔上囊绝对质量逐渐增高;腔上囊生长指数21日龄达最高;黏膜大皱褶高、宽度、淋巴滤泡面积、皮质宽度均不断增加;小结相关上皮向腔面形成突起,并不断增高增宽。结果表明,雏鸭腔上囊1～14日龄生长较为缓慢,14～35日龄生长较快,35～49日龄发育基本趋于稳定,其中21～28日龄是雏鸭腔上囊生长发育的高峰时期,28日龄时,雏鸭腔上囊组织结构基本发育成熟。     

鸡传染性法氏囊病的防制

鸡传染性法氏囊(又称腔上囊)病,是由法氏囊病毒引起的一种急性接触性传染病,仅鸡发病,发病日龄以14日龄多见,近年来有所提前,最早的有7～5日龄发病的,鸡场里,初次暴发本病通常危害最严重,后代再发生本病时就轻得多.     

高氟对雏鸡法氏囊形态结构、细胞周期和凋亡影响的研究

为研究高氟对雏鸡法氏囊的影响,选用1口龄AA肉鸡健雏300只,随机分为4组,分别饲以对照日粮(F23 mg·kg-1)和高氟口粮(F 400 mg·kg-1,高氟Ⅰ组;F 800 mg·kg-1,高氟Ⅱ组;F 1 200 mg·kg-1,高氟Ⅲ组)42d,以实验病理学和流式细胞术的方法观察雏鸡法氏囊的变化.结果显示高氟Ⅱ组和高氟Ⅲ组法氏囊绝对质量和脏器指数显著低于对照组(P<0.05或P<0.01),法氏囊淋巴细胞明显减少.经流式细胞仪测定,高氟Ⅰ组细胞周期与对照组相比差异不显著(P>0.05),高氟Ⅱ组和高氟Ⅲ组则出现明显变化.14日龄时高氟Ⅱ组和高氟Ⅲ组法氏囊淋巴细胞G0/G1期显著升高(P<0.05),G2+M期和增殖指数(PI)与对照组相比不同程度地降低;28口龄时高氟Ⅱ组和高氟Ⅲ组S期显著升高(P<0.01),凋亡率也显著升高(P<0.01);42 日龄时高氟Ⅱ组和高氟Ⅲ组G0/G1期显著升高(P<0.01),S期、G2+M期和增殖指数(PI)显著降低(P<0.01),同时凋亡率显著高于对照组(P<0.01).电镜观察,42日龄时高氟Ⅱ组和高氟Ⅲ组法氏囊可见多量的凋亡淋巴细胞及淋巴细胞线粒体肿胀.结果表明,日粮含氟达800及1 200 mg·kg-1时可引起法氏囊淋巴细胞增殖分化受阻,凋亡细胞显著增多,法氏囊生长发育受抑制,机体体液免疫功能受损.     

Histologic characterization of the involuting bursa of Fabricius in single-comb white Leghorn chickens

Bursas from specific-pathogen-free white leghorn chickens of both sexes were examined at several intervals from hatching to 28 weeks of age. No histologic alterations other than scattered atrophic or cystic follicles were observed through 20 weeks. Obvious involution, first noted at 24 weeks, was in early stages in females and quite advanced in males. Involution was essentially complete by 26 weeks, and only cicatrized vestiges of bursas were present at 28 weeks of age. Gross manifestations included bursal atrophy, variable yellowish discoloration of the mucosa, and matting or total loss of identity of the mucosal plicae. Histologic characteristics of involution are summarized by the following approximate sequence: atrophy and exfoliation of plica epithelium; subepithelial stromal fibrosis; fusion and ultimate collapse of plicae; liquefactive necrosis of first medullary then cortical elements of follicles, which seemed to progress from basal to apical portions of the plicae; progressive proliferation of stromal connective tissue and infiltration of macrophages into areas occupied by necrotic follicles; and, finally, complete fibrous organization of luminal debris, leaving a firm nodule formed by a contracted muscularis surrounding the cicatrized remains of the mucosa.     

Functional restoration of the bursa of Fabricius following in ovo infectious bursal disease vaccination

The primary role of the avian bursa of Fabricius is to provide an essential microenvironment for B-lymphocytes to diversify their immunoglobulin genes by gene hyperconversion. Infectious bursal disease (IBD) vaccination using intermediate plus vaccine strains can temporarily deplete the bursal follicles and interrupt the normal B-cell development, which is generally followed by B-cell repopulation and histological regeneration. To find evidence that functional restoration of the bursa of Fabricius occurs in addition to the histological regeneration, we have analysed the chB1 gene expression, which indicates active bursal B-lymphocytes, and also the surface expression of a carbohydrate structure Lewis(x), a marker which identifies those bursal B-lymphocytes that are undergoing gene hyperconversion. In ovo vaccination with an immune complex vaccine (IBDV-BDA) caused transient bursal destruction in both the SPF and the maternally protected broiler groups with differences evident in the starting time, the severity and the duration of the effect. After the depletion phase, signs of histological regeneration appeared together with chB1- and Lewis(x) expression indicating that B-lymphocytes were functionally active and the bursa of Fabricius was serving again as an efficient primary lymphoid organ providing an appropriate microenvironment for B-cell development.