الفهرس 
Approval sheetOnly 14 pages are availabe for public view
 |  | from | 201 |  |  |
| | | from | 201 | | |
Abstract
This work was carried out on the thymus, kidney and spleen of 50 apparently healthy Tilapia nilotica. The thymus of Tilapia nilotica was covered by thin capsule that arises short trabeculae. The parenchyma differentiated into cortex and medulla. The parenchyma also contained pigmented macrophages, mast cells, erythropoietic tissue and capillaries. Some regions of the thymus contained apoptotic thymocytes and vacuoles. The kidney of Tilapia nilotica was differentiated into two parts; head and trunk kidneys which were connected directly; the head kidney was covered by thin connective tissue capsule and contained an extensive haemopoietic and lymphoid tissue with pigmented granules inbetween. Head kidney could not differentiated into cortex and medulla. The trunk kidney, the interstitial tissue were represented by haemopoietic tissue, lymphoid tissue and melano-macrophages. There were pleomorphic cells with basal located nuclei located in the renal tubules. The spleen of Tilapia nilotica was covered by thin capsule. The spleen was composed of red, ill developed white pulp and accumulation of melano-macrophages. Key words: Thymus, head kidney, trunk kidney, spleen, Tilapia nilotica.