Indicators of the leukocite system of the blood of the tesselated water snake Natrix tessellata of the northern and eastern Pre-Caspia

Snakes have a well-developed hematopoietic and immune system, demonstrate responses to the full range of environmental factors and are a unique object for environmental research. The issues of assessing the immune status of snakes under the influence of anthropogenic press in different biotopic environmental conditions remains poorly understood. Therefore, it is particularly relevant to search for population markers that allow us to assess the work of the effector mechanisms of the immune system determining the process of forming adaptive responses of the body. The aim of the work was a comparative assessment of the leukocyte blood system of the tesselated water snake Natrix tessellata (Laurenti, 1768) of the Northern and Eastern Pre-Caspian. The lymphocyte-granulocyte composition of peripheral blood of the water snake Natrix tessellata was characterized by a predominance of agranulocytes (70-75 %), the proportion of granulocytes was 25-30 %. The redistribution of the ratio of granulocytes to agranulocytes was established in the blood of individuals of the studied populations from different biotopes. The content of heterophiles, monocytes was increased and content of lymphocytes was reduced in individuals of the Eastern Pre-Caspian compared with individuals of the Northern Pre-Caspian. Intersex differences were observed in the content of azurophils, the proportion of which in the blood of females of the water snake from the Northern Pre-Caspian was higher compared to males. Integral indices (ISGE, ILG, ISGL) revealed the same type of variability in the parameters of the blood leukocyte system of females and males living in the areas of the Caspian lowland. The revealed differences in the parameters of the white blood cell system of water snakes may be related to their seasonal ontogenetic activity. The non-specific protective system of the blood of snakes responds faster and more effectively to a wide range of pathogenic antigens of the environment, compared with adaptive responses. Consequently, during the mating period, it is the innate defense system, characterized by higher development in ectothermic animals that provided maximum protection and stable functioning of the body.