Structural and functional organization of central organs of hematopoiesis and immune protection of piglets during the early postnatal period of ontogenesis

Abstract

Factors of the environment and anthropogenic factors have an negatively influence on the body of newnate animals, especially with unfinished morphofunctional status, which often leads to a decrease in the resistance and development of immunodeficient conditions. The thigh bone, 9th thoracic vertebra and thymus of piglets were studied during the early postnatal ontogenesis (1-, 5-, 10-, 15-day-old age) of Ukrainian white breed, which was reared in accordance with traditional technologies. The dynamics of absolute, relative mass of organs, relative area of tissue components and centers of ossification of bones were determined by means of histologic, X-ray and morphometric methods. It has been established that in neonates and piglets of the neonatal period, the morphofunctional status of blood formation and immune protection central organs is determined by the ratio of parenchymal and stromal tissue components, which affects the realization of adaptive capabilities and viability of animals. In the thigh bone of the newborn piglets, all main and secondary ossification cells are developed, and in the 9th thoracic vertebra only diaphyseal. The bone marrow is clearly differentiated into osteoblastic, red and yellow; the degree of development, the peculiarities of localization and structure of each of them are determined by the morphofunctional status of components of microenvironment-bone and cartilaginous tissues. The bone tissue is divided into primary tissue, which is located in the zones of bone growth and is filled with osteoblastic bone marrow, and the secondary spongy bone, which is localized in epiphyses and diaphyses with red bone marrow, fat cells, and also compact bone. The peculiarity of the tissue organization of the thymus is the development of connective tissue and a special reticuloepithelial stroma, as well as the differentiation of lymphoid tissue on the cortical and brain areas with a clear boundary and the presence of the brain layered epithelial cells (the presence of Hassall's corpuscles (thymic corpuscles bodies) in the brain. In piglets of the neonatal period, in the organs of universal hemopoiesis, the number of red and yellow bone marrow, as well as bone tissue increases, and while-osteoblastic bone marrow and cartilage tissue decreases. In the central organ of lymphocytopoiesis, the thymus, the increase of lymphoid tissue occurs.