Abstract
The aim of this research was to study bone marrow architectonics and the peculiarities of hematopoiesis of turkeys cross «Converter». To study the hemopoiesis at the age of 50 days, the samples of the red bone marrow from the femur were selected. Samples were prepared according to standard methods for histological and cytological examination. Four lineages of hematopoiesis (erythrocytic, monocytic, granulocytic and platelet) were isolated from the bone marrow of turkeys. The erythrocytic lineage was represented by erythroblasts, rubricytes and mature erythrocytes. In the process of maturation, the erythroblast initially uniformly decreased, turning into rubricyte. Then the cytoplasm and nucleus enlarged and acquired an oval shape. A mature erythrocyte was formed. Hematopoiesis of eosinophils and basophils in turkeys was similar to hematopoiesis in mammals. They also formed from myeloblasts. At the stage of promyelocyte, granularity of the cytoplasm appeared. At the stage of myelocyte, the number of granules increased, and the granularity acquired a typical shape and color. Then the nucleus acquired a rod-shaped form, and after it was segmented into 2–5 segments. Heterophiles were divided into two types (with rounded and elongated granules). Heterophile granules were about 2 times bigger than eosinophils, and cytoplasm granularity was significantly sparser. Monocytes in turkeys had a rounded cytoplasm, in which small granules were sometimes present, and the nucleus was shifted to the periphery. Mature monocytes differed from promonocytes in a smaller nuclear-cytoplasmic ratio. Platelets had a centrally located nucleus and an oval cytoplasm with granules inside. Prothrombocytes were approximately 1.5 times larger than mature platelets. The lymphoid lineage is not represented, which indicates an extramedullary lymphopoiesis. A significant difference was the absence of megakaryocytes and the development of platelets from thromboblasts. Granulocytic and monocytic lineages were similar to those in mammals, and erythroid one was represented only by nucleated erythrocytes.