Peculiarities of hemopoisis in sturgeons species (Acipenseridae) (a review)

Purpose. To analyze data from scientific sources of information regarding the species-specific features of the hematopoietic and histo-morphological characteristics of hematopoietic tissues and organs of sturgeons (Acipenseridae). Consider the general aspects of their structure at different stages of ontogeny. To present the general features of differentiation and proliferation of blood elements. Findings. A review of scientific papers and literature has revealed that hematopoiesis in sturgeon species of fish differs significantly from that of mammals (Mammalia), but also from other fish from cartilaginous (Chondrichthyes) and bony (Osteichthyes) classes. Moreover, sturgeon fishes are characterized by a species-specificity in the development of hemopoiesis organs on each stage of ontogenesis. The age-related changes of the developing blood cells, ranging from blast elements (erythroblasts, lymphoblasts, monoblasts, myeloblasts) to the appearance of mature (definitive) forms, are marked. The specific heterochrony is revealed in the development of sturgeon blood cells. The organs of hemopoiesis are: hemopoietic cranial or lymphoid organ, gills, spleen, heart, thymus, gastrointestinal tract (anterior part of the digestive canal, pyloric gland, middle intestine, spiral valve and liver) and kidneys (pronephros and mesonephros). Hepatic hematosis begins to be realized during the larval period of development from a massive spread near the vascular connective tissue. A little bit later in the age of 15 days of active feeding, a similar spread covers practically all area of the body. At this time in liver hepatocytes and reticular cells with developing blood corpuscle are precisely allocated. In this period, proliferation of all cellular lines: erythropoietic, lymphocytopoietic, myelocytopoietic, and also thrombocytopoiesis take place in liver. The plasmocyte differentiation occurs in cranial haematogenic organ of sturgeon. In reticular tissue of lymphoid organ, thrombocyte precursors — megakariocytes were found. Mesonephros is a hemopoietic organ, which first starts to perform the hemopoietic function, and executes it until the end of the life cycle of fish. Cell development of erythropoietic and lymphocytopoiesis series is over in the prolarvaperiod of the development in the hematopoietic tissue of the kidney, and the formation of the granular series occurs in the larval period, and eosinophilic myelocytes are marked much earlier than in other hematopoietic organs (the 43 stage of the development), and a bit later — neutrophil myelocytes. Practical value. Systematized data on the specifics of hematopoiesis processes and patterns of development of hemopoietic organs in sturgeon species will be useful both for researchers and fish farmers. This is due to the fact that the course of hemopoiesis most fully reflects each specific stage of the development of sturgeon species, being an instant reaction of a number of body tissues to any changes in the internal and external environment.