Biochemical Blood Serum Indices in a Male American Mink (Neogale vison) Involved in Selection for Tame and Aggressive Behavior

Artificial selection of animals, aimed at enhancing or attenuating their defensive response to humans, influences the variability of their regulatory systems and physiological functions, as well as the seasonality of reproductive and metabolic cycles. Meanwhile, such a selection has not ever been paralleled by biochemical profiling of animals’ blood serum. The American mink Neogale vison, the seasonally breeding predator of the Mustelidae family, served a model object in studying the influence of selection on mammalian physiological functions. Over 27 generations of long-term selection for defensive responses to humans, two American mink strains were bred, characterized by distinctly aggressive and tame behaviors, atypical for animals in industrial populations. The aim of this work was to analyze serum biochemical indices in tame vs. aggressive cage-raised American mink in the summer vs. fall seasons. It was shown that both the season of the year and the behavioral type of animals influence serum biochemical indices. For instance, total protein, bilirubin, glucose, and uric acid levels were higher, while alkaline phosphatase (ALP) activity was lower in fall compared to summer, regardless of the behavioral type. Aggressive animals exhibited higher amylase activity and triglyceride levels but lower lipase activity in fall compared to summer. In the tame mink, aspartate aminotransferase (AST) activity and cholesterol levels were higher in fall compared to summer. Aggressive vs. tame animals were characterized by higher albumin, glucose, and cholesterol levels, as well as higher AST, lactate dehydrogenase (LDH), and lipase activity in summer, while demonstrating higher glucose and LDH but lower urea and ALP levels in fall. Thus, serum metabolic indices in the American mink undergo changes during long-term behavioral selection, while individual biochemical parameters retain seasonal fluctuation, reflecting evolutionary adaptation of the American mink to cyclic environmental changes.