HISTOMORPHOLOGICAL STUDY OF THE MAJOR LYMPHOID TISSUES IN INDIGENOUS DUCKLINGS OF BANGLADESH
Keywords:Histomorphology, thymus, bursa, spleen, ducklings
A histomorphological study was performed in the major lymphoid tissues (thymus, bursa of Fabricus and spleen) of the six 21-day-old indigenous ducklings of Bangladesh by H & E staining method during the period from March to May 2011. In the present study, it was observed that the thymus was enclosed by a thin connective tissue capsule. Numerous fine septa of connective tissue originated from the capsule and divided the organ into incompletely separated lobules. Each lobule organized into a peripheral cortex and a central medulla. The bursa of Fabricus was consisted of mucosal folds (plicae). Numerous follicles filled the lamina propria of each fold and each bursal follicle was composed a peripheral cortex and a central medulla. A layer of undifferentiated epithelial cells occupied the periphery of the medulla, which was separated from the cortex by a capillary layer. The darkly stained cortex was composed of many closely packed small lymphocytes. The paler medulla contained fewer cells of various sizes. The spleen was surrounded by a thick splenic capsule and there were a small number of trabeculae. The white pulp was composed of network of reticular cells and reticular fibers within various size lymphocytes and plasma cells were diffusely distributed. The red pulp of the spleen was formed from venous sinuses and anastomosing cord of reticular cells, macrophages, lymphocytes and blood cells. The length and breadth of the thymic lobules, bursal follicles and white pulp of the spleen were 226.68 and 165.78cm, 204.45 and 138.23cm, and 129.05 and 103.43cm respectively. The result of the present work revealed that the immunocompetent cells were arranged scatteredly or densely as an unorganized lymphatic nodules in the lymphoid tissues. The length and breadth of the thymic lobules were higher followed by bursal follicle and splenic white pulps were varied within the lymphoid tissues and even one another in indigenous ducklings. The results of the present study indicate that the architecture and distribution of lymphocytes and lymphoid follicles of ducklings is very close to the chicken and this study might be helpful to understand the changes in the frequency of the population of immunocompetent cells in drug induced, vitamin and mineral supplemented or hormone treated duck in future.
Bangl. J. Vet. Med. (2011). 9(1): 53-58