Comparative data on the blood leukocyte composition of semi-aquatic turtles from the Samara Zoo

Abstract

The leukocyte blood count of 16 species of five families of semi-aquatic turtles from the Samara Zoo was determined. A comparison of the leukogram of representatives of two genera of the family Emydidae revealed a reduced proportion of heterophils and an increased proportion of basophils in Graptemys (G. pseudogeographica, G. nigrinoda) compared with Terrapene (T. triunguis, T. ornata). The leukocyte profile of Cuora mouhotii (Geoemydidae) was characterized by an increased content of heterophils, which showed a higher activation of innate immune responses. The most similar in leukocyte composition are the species of the Kinosternidae family of three genera: Kinosternon, Sternotherus and Staurotypus. The clade Trionychia (Trionychidae) differed from the clade Durocryptodira (Emydidae, Geoemydidae and Kinosternidae) by an increased number of heterophils and monocytes, and a low content of eosinophils. The Pleurodira suborder (Chelidae) differed from the Cryptodira suborder (Emydidae, Geoemydidae, Kinosternidae, Trionychidae) by an increased content of agranulocytes. Positive significant correlations of the length of the carapace with the content of heterophils and the values of leukocyte indices (index of the eosinophils and lymphocytes ratio, index of the heterophils and eosinophils ratio, index of the heterophils and lymphocytes ratio) reflecting the increased role of nonspecific resistance of the turtle organism during ontogenesis and negative significant correlations with the content of eosinophils were revealed. The index of the heterophils and lymphocytes ratio, which is an indicator of physiological stress, had the minimum value among the studied species in Sternotherus odoratus (Kinosternidae), the maximum value in C. mouhotii (Geoemydidae).