The improvement of blood smears coloring for the determining of fish cytometric blood parameters

Abstract

Blood plays the role of a sensitive indicator of fish health. As an indicator of the degree of contamination of reservoirs it is possible to use cytometric indices of red blood cells of fish. Erythrocytes of fish are sensitive to environmental pollution and their morphological changes can be used as a bioindicator of the toxicity of the aquatic environment, and those or other pathologies of blood cells can be caused by certain pollutants. The disadvantage of existing methods of blood smears coloring is that they are inconvenient in the field conditions, when it is necessary to examine the fish blood during ichthyological researches or they are long-lasting. In this regard, there is a need for a fast and reliable method of coloring blood cells of fish, which can be used both in laboratory and in field conditions. The aim of the work was to improve the method of coloring fish blood smears for easier and faster execution, without degradation of the quality of colouring. The proposed method of coloring fish blood smears was tested on the basis of the laboratory of the Department of General Biology and Water Bioresources of the Oles Gonchar Dnipro National University. The subject of the research was the young carp fish (Cyprinidae). The improved method is based on the classic method of painting by Papenheim, but differs in the interval of time devoted to colouring in a solution of the dye Romanovskogo. Blood swabs were examined under a Ulab XY-B2TLED microscope (40X lens enhancement) using a microscope with a Sciencelab T500 5.17 M digital camera. The analysis showed that erythrocytes on medicine that were in the Romanovsky solution for 5 minutes had the correct form with clear contours, a dark purple core located in the center of the cell. It has been found that this method can be used in cytometric researches to determine such indicators: large longitudinal and small transverse diameters of erythrocytes, erythrocyte area, erythrocyte core area, nuclear-cytoplasmic ratio, percentage of mature and immature erythrocytes and their forms. It can also be used in analyzing the presence of erythrocyte pathologies. It has been established that reduction of time (from 20 minutes to 5 minutes) of preparations in the dye solution of Romanovsky does not affect the quality of their coloring, and therefore it is a reliable and fast way that can be successfully applied in morphological and cytometric studies of blood of fish.