Morphology of the small intestinal mucosa in chickens of different sexes

The structure of the mucous membrane of the small intestine in chickens of different sexes was studied. The Isa-Brown crossbred chickens were divided into two groups: males and females. In the birds’ small intestine, the volume of the entire mucosa and its individual structural parts (muscularis mucosae, crypts, villi) was investigated. The volume of connective tissue fibers located in the crypt area was also determined. The sex of the chickens has a pronounced influence on the indicators value. In males, 73.9 % of the mucosa volume is occupied by villi; 21.8 % by crypts; 4.3 % by the muscularis mucosae. In females, this ratio is 80.6 % – 15.7% – 3.7 %. Males have larger volumes of the muscularis mucosae and crypts. Females dominate only in terms of villi volume. The mucosa total volume has higher values in females, which exceed males in the duodenum by 1209.4 mm3 (P < 0.05), in the jejunum by 2719.5 mm3 (P < 0.05) and in the ileum by 424.2 mm3. In males, 70.4 % of the villi volume is occupied by the epithelial layer, and 29.6 % by the basal lamina. In females, this proportion is 74.8 % and 25.2 %. At the same time, in the entire small intestine, the largest values of the epithelium volume belong to females. They also have higher basal lamina volume of the villus in the jejunum and ileum. Connective tissue fibers support the structure and mechanical properties of the intestinal wall. Along the entire small intestine, the collagen fibers volume is greater in males, and elastic fibers in females. The males’ duodenum contains 12.3 % of the small intestine collagen fibers, the jejunum – 75.9 %, the ileum – 11.8 %. In females, the proportion of collagen fibers in this area is: 16.7 %, 73.4 % and 9.9 %, respectively. The proportion of elastic fibers in the males’ duodenum is 22.2 %, in the jejunum – 69.2 %, in the ileum – 8.6 %. In females, the distribution of elastic fibers along the intestinal wall is: 17.2 % – 73.7 % – 9.1 %. The presented sexual features of the small intestine mucosa morphology of chickens demonstrate its adaptive capabilities in accordance with the physiological state of the organism.