Comparative Research into the Effect of Vitamins A and E on the Differential Leucocyte Count and the Morphometric Parameters of Lymphocytes in Carnivorous Mammals (Carnivora)

Abstract

Study into the effect of vitamins A and E on total and differential leukocyte count, as well as morphometric parameters of lymphocytes in three carnivorous species—dark brown American mink (Neovison vison, Mustelidae), blue fox (Vulpes lagopus, Canidae), and silver fox (V. vulpes, Canidae)—was conducted. The highest white blood cells count (WBC count) and the largest surface area of lymphocytes and their nuclei in the peripheral blood were observed in mink, while the lowest indices were found in silver fox. Additional supplementation with vitamins A and E for 14 days had no effect on the WBC and differential leukocyte count, except for silver foxes receiving vitamin E, in which a decrease in relative eosinophils and monocytes content was observed. The action of vitamins was mainly manifested in changes in the lymphocytes’ morphometric parameters. The addition of vitamin A into the diet of mink and silver fox and vitamin E into only mink’s diet led to an increase in the surface area of lymphocytes and, in some cases, their nuclei, which was accompanied by a rise in the cytoplasm size in mink cells. In blue fox, on the contrary, both vitamins induced a decrease in the surface area of the lymphocytes and their nuclei. The observed changes may be associated with the immunomodulatory effects of vitamins A and E of the studied species of carnivorous mammals, while the found differences may be associated with features of the morphologic and functional organization of lymphocytes and the immune status.