Electron Microscopic And Immunohistochemical Studies Of Spleen, Thymus And Caecal Tonsil In Chicken (Gallus domesticus)
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Title |
Electron Microscopic And Immunohistochemical Studies Of Spleen, Thymus And Caecal Tonsil In Chicken (Gallus domesticus)
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Creator |
Kannan, T.A.
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Contributor |
Ramesh, Geetha
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Subject |
livestock, biological phenomena, diseases, cytoplasm, cytoplasmic organelles, germinability, nucleus, wood, thinning, animal tissues
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Description |
Light and electron microscopic and immunohistochemical studies on spleen, thymus and caecal tonsil were done in layer chicken of various age groups ranging from day-old to forty weeks. The spleen was encapsulated by a connective tissue capsule and the trabeculae were poorly developed in all the age groups studied. The major cellular population of the white pulp included lymphoblasts, lymphocytes of various sizes, follicular dendritic cells and reticulum cells. PALS were found adjacent to the central artery. The splenic red pulp was composed of pulp cords consisted of erythrocytes, reticular cells and lymphocytes of various sizes, macrophages, granulocytes, plasma cells and mast cells. The arterioles that continued into the red pulp formed sheathed capillaries or ellipsoids. The thymic gland in chicken showed a thin connective tissue capsule. The connective tissue septa divided the gland into lobules with a dark outer cortex and a pale inner medulla. In thymic parenchyma, lymphocytes or thymocytes,retiucloepithelial cells, myoid cells and macrophages were the predominant component and the other cell types occasionally observed were erythrocytes, granulocytes, mast cells and plasma cells. Three types of reticuloepithelial cells were observed. The first and second types were distributed both in cortex and medulla. The third type was noticed in medulla and at the cortico-medullary junction. The Hassall’s corpuscles were composed of concentrically arranged reticuloepithelial cells. The centre of the corpuscles appeared either solid or cystic. The myoid cells of the chicken thymus were found mainly in the medulla. In the present study, intracellular and intercellular cysts were observed in association with the Hassall’s corpuscles in all the age groups. The onset of involution was observed in twenty week-old birds and marked involutary changes were noticed in forty weeks. The caecal tonsil revealed two types of lymphoid aggregations (germinal centre). The first type had an incomplete capsule and the second type was found encapsulated with connective tissue. The capsule of the germinal centre consisted of many layers of flattened reticular cells separated with an intercellular substance. The germinal centre consisted of lymphoblasts, lymphocytes of various sizes, reticular cells, plasma cells, mast cells and macrophages. In forty week-old birds, the lymphocytic population was observed to be comparatively reduced and more number of fibroblasts and collagen fibres were noticed. The caecal tonsil also had M cells with short and irregular microvillus. A distinct difference was observed in the ratio of CD4 and CD8 cells in the spleen and thymus of different age groups. Nevertheless, the ratio narrowed down at forty weeks of age. Flow cytometric analysis of CD4 and CD8 in the spleen and thymus from control and Eimeria tenella infected birds reflected the participation of these organs in cell mediated immunity. |
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Date |
2016-05-30T10:02:58Z
2016-05-30T10:02:58Z 2008 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/66438
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Language |
en
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Format |
application/pdf
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Publisher |
Tamil Nadu Veterinary and Animal Sciences University
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