Selection for behavior and hemopoiesis in American mink (Neovison vison)

It has been known that selective breeding of animals for behavior associated with domestication changes a variety of physiological traits including response to stress and hypothalamo-pituitary-adrenocortical system activity. The aim of our research was to find association between behavioral type and differential leukocyte counts as an indicator of homeostasis activity. We used farm-raised 5-month-old minks (Neovison vison) that had been selective bred for 17 generations on the basis of behavior toward human. After selection, minks were divided into the following groups: aggressive (from −4 to −1), “domestic” (from +1 to +5). Blood leukocytes were analyzed in 5-month-old minks (n = 105) of different behavior lines: aggressive (−1, −2), “domestic” (+1 and from +3 to +5), fearful, and minks never subjected to selective breeding (control). We found strong effects of selection for behavior of minks on differential blood leukocyte count. There were differences between behavior types in differential leukocyte counts. Neutrophils and eosinophils were the leukocyte types the most sensitive to selection for behavior. The counts of eosinophils in peripheral blood in “domestic” (+3, +5) minks were higher than in control and aggressive (−2) minks. The percentage of neutrophils was higher in the most aggressive minks (−2) in comparison to “domestic” minks. We have concluded that differences found in leukocytes profile are the result of neuroendocrine system modification.