The study of the macro- and microstructure of organs in commercial wild fur-bearing animals is of scientific and practical interest, and allows identifying useful traits that can be used in selection work in the industrial breeding of animals. The purpose of this work was study the macro- and microstructure of the liver and pancreas, as well as to determine their absolute and relative mass in the American mink (Neogale vison, Schreber, 1777), living in the forests of the Eastern Upper Volga region. As a result, it has been found that the liver has 6 lobes, while the caudate and mastoid processes are well developed. The hepatic lobules are unremarkable, with an evident beamed structure, the boundaries between hepatocytes are blurred, the nuclei are located in the center. In some individuals, the cytoplasm has a net-like structure characteristic of albuminoid degeneration; clumps of hemosiderin are found in large vessels. The pancreas consists of six or seven separate lobules, located in the mesoduodenum. From the surface it is covered with a capsule of dense fibrous formed connective tissue, from which thin trabecules extend. In the lobules of the gland, acini are compactly located, between which thin connective tissue layers with small capillaries are revealed, the interlobular ducts are surrounded by loose connective tissue. The lobules contain medium-sized islets of Langerhans, consisting of an accumulation of small cells pierced by capillaries. The absolute weight of the liver is 43.0–48.0 g, the relative weight is 3.7–4.0 %; of the pancreas, respectively, 4.3–5.0 g and 0.38–0.43 %. The morphostructure of the organs of the free-living American mink does not differ significantly from the liver and pancreas of minks, raised on fur farms. The revealed changes in the liver are due to the specific diet of animals.

Ponomarev Vsevolod A., Kletikova Lyudmila V.

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