Lymphoid tissue pattern in the walls of small and large intestines in American mink (Neovison vison)

Abstract

When breeding minks, a lot of problems are associated with disturbances of reproduction, birth of weak offspring, metabolic disorders, weakening of immunity. Poor knowledge of the morphology of mink and lack of detailed information about their immune system is among appropriate reasons. The largest variety of antigens enter the body with food and water, through the wall of gastrointestinal tract. The first barrier to their penetration is lymphoid tissue associated with mucous membranes, thus causing changes in immune structures. Our purpose was to study the syntopia, morphology and quantitative characteristics of intestine-associated lymphoid tissue in American mink (Neovison vison). A biomaterial for the study was organocomplex of the small and large intestines from 11 American Minks at the age of 8 months, obtained from the fur farm “Vyatka” (Zonikha, Slobodsky district, Kirov region). In the walls of small and large intestines, both single and grouped lymphoid nodules are found. Single lymphoid nodules are detected in lamina propria of the mucous membrane and in the submucosa, along the entire length of the intestines, except of the ileum. Lymphoid nodules are round or oval, distributed diffusely, their density per 1 cm2 is in duodenum – 0.62±0.08; in jejunum – 1.88±0.32; in colon – 9.21±0.28; in rectum – 24.2±0.42. At the border of pyloric part between the stomach and duodenum, single lymphoid nodules form an intestinal-pyloric lymphoid ring; at the site of transition from rectum to the anal sphincter, the rectal lymphoid ring is observed. Abundance of lymphoid nodules in rectal area is associated with semi-voluntary management of animals, and retention of fecal mass in this part of intestine. By two lymphoid plaques are found in the duodenum; 6 to13, in the jejunum; one large striped (lingual) lymphoid plaque is found in the ileal wall; 1 to 3 plaques are found in the colonic wall. Presence of lymphoid plaques in colonic wall of American mink should be considered a protective/adaptive phenomenon, due to absence of coecum in the animals from Mustelid family. The revealed patterns of lymphoid tissue syntopia in American mink are associated with antigenicity of food substances and terms of their presence in the ileum, colon and rectum.