In the dissertation, new results of complex morphological studies are presented, the task of which was to establish the features of the morphofunctional organization of the gut of domestic ducks during the first year of the postnatal period of ontogenesis.
It was found that the body weight of ducks of the black white-breasted breed in the period from one day to 365 days of age increased 55.4 times. The most intensive – 15.9 times, the increase in body weight occurred in the first month. During this period, the absolute weight of the intestine increased 114.7 times, and the length – 4.3 times. The gut acquired the maximum absolute weight at the age of 1, relative weight at 21 days of age, and length at 180 days of age. During the first week, active processes of histogenesis and morphogenesis occur in the gut of ducks, characterized by the formation of villi and crypts, an increase in the content of cells and collagen fibers in the fibrous loose connective tissue of the mucous membrane, and the number of smooth muscle cells in the villi. Based on the results of determining the average age index of the microstructures of individual intestines, the main regularities of their structure were determined. The duodenum is characterized by the highest indicators of wall thickness, absolute and relative thickness of the mucous membrane, height, width, surface area, density of villi and crypt depth. The jejunum has the maximum density of crypts, the ratio of the height of the villi to the depth of the crypts. The ileum is characterized by the highest rates of crypt density, and the cecum is characterized by the highest rates of the relative thickness of the inner layer of the muscular membrane. The rectum has the largest indicators of diameter, thickness of the muscular membrane, the thickness of the muscular plate of the mucous membrane.
A feature of the enteroendocrine system of domestic ducks is an increase in the number of its cells from hatching to 21 days of age, followed by a decrease in older age. During the first year of life, the highest content of argentafinn and argyrophilic endocrine cells was found in the ileum and cecum, the lowest in the duodenum. The most common type of endocrinocyte is argentafinn cells. The enterosympathetic nervous system of domestic ducks is represented by the submucosal plexus and the myenteric plexus. During the first year of life, it contains approximately the same number of ganglions, the general age pattern of which is an increase in their area and a decrease in the density of neurons. A decrease or increase in the morphometric parameters of the ganglions of a relatively younger age indicates the plastic state of the intestinal nervous system. Along with the general age-related regularity of changes in the morphometric parameters of intestinal microstructures, a characteristic feature of their dynamics is a different degree of reliability of an increase or decrease in the value of their indicators relative to the previous age.
