Annual variation of red blood cell number and composition of erythroid cells in circulating blood and head kidney of golden grey mullet (Chelon auratus Risso, 1810)

Abstract

The changes in the number of erythrocytes in the blood and the production of erythrocytes by the hematopoietic tissue of the golden grey mullet (Chelon auratus Risso, 1810) during the annual cycle were studied. Catching and delivery of fish to the aquarium was carried out monthly. The content of immature erythroid forms was determined: pronormoblasts, basophilic and polychromatophilic normoblasts, in the head kidney (pronephros) and circulating blood. It has been established that the processes of erythropoiesis in the hematopoietic tissue of the golden grey mullet proceed irregularly. The active production of erythroid mass is mainly confined to the post-spawning period. This is evidenced by an increase in the content of immature erythroid forms in the head kidney and blood. This coincides with a general increase in the number of red blood cells in the circulation system and indicates a shift in the erythrocyte balance in favor of production processes. In the rest of the time, the processes are opposite. It is assumed that this is due to the peculiarities of the organization of the red blood system, which excludes the regular production of erythropoietin in the kidneys.