As evidenced by the publications of recent years, contrary to the existing dogma about the immutability of the state of the enteric nervous system during the postnatal period of ontogenesis, the population of intestinal neurons is a dynamic formation, decreasing with age and changing due to the action of environmental factors. The current article presents the results of study of the microscopic structure of the nerve plexus of the muscular membrane of the enteric nervous system of domestic ducks (Anas platyrhynchos domesticus) of the black white–breasted breed, of nine age groups of 1–365 days of age. The topography, number, area of nerve nodes, as well as the density of neurons in them were determined on transverse sections of the duodenum, jejunum, ileum, caecum and rectum. For the purpose of a generalized assessment of the morphofunctional state of the nerve plexuses, two parameters were determined: the average age indicator of the gut and intestines. The average age indicator of a certain structure of each intestine was determined as the arithmetical average of its nine age indicators. The average age indicator of a certain gut structure was determined as the arithmetic average of the average age indicator of the structure of all five intestines. It has been established that the nerve plexus of the muscular membrane (myenteric, plexus Auerbachi) of the gut of domestic ducks, in contrast to mammals, is not located between the layers of the muscular membrane, but in its outer layer. On a transverse section of the gut wall, the myenteric ganglia and cords that connect have a predominantly elliptical shape. Despite a significant increase with age in the diameter and thickness of the gut wall, the total number of myenteric ganglia changed little, increasing or decreasing with varying degrees of reliability relative to the previous age. In the gut of ducks, during the first year of the postnatal period of ontogenesis, the smallest number of myenteric ganglia was found in the cecum, and the largest – in the ileum. The general pattern of the dynamics of the size of the myenteric ganglia of the gut of ducks was an increase in their area with age. Moreover, this indicator reached the greatest value at different ages of ducks: at 30 days of age in the ileum and cecum, at 180 days of age – in the rectum and at 365 days of age – in the duodenum. The smallest area of the myenteric ganglia was found in the jejunum, and the largest – in the duodenum and ileum. The smallest number of neurons in the ganglion was found in the cecum, and the largest – in the rectum, the lowest density of neurons in the ganglion was found in the cecum, and the largest – in the jejunum. The general quantitative pattern of neurons in the ganglion was the decrease in their density with age. Changes in the morphometric parameters of the ganglia of the nerve plexus of the muscular membrane of the ducks’ gut indicate the plasticity of the enteric nervous system, its ability to dynamically respond to the action of factors of the internal and external environment. It is promising to study the state of the submucous nerve plexus, as well as the cellular composition of the population of neurons of the enteric nervous system of domestic and wild poultry.

The aim of work was to determine the features of the microscopic structure of the lamina muscularis mucosae of the goose gut during the postnatal ontogenesis. According to the review of the literature, during the characterisation of the structure of the intestinal mucosa, researchers first pay attention to the condition of the villi, crypts, epithelial layer and their morphometric parameters, leaving the lamina muscularis mucosae aside. The intestinal lamina muscularis mucosae is an under-researched structure of the intestinal wall, the information on which is fragmentary and contradictory. The middle parts of the duodenum, jejunum, ileum, cecum and rectum of large grey geese of 13 age groups were investigated. The classic histological methods of staining by hematoxylin and eosin, aniline blue – orange (by Mallory), as well as azure II – eosin were used. It was established that the lamina muscularis mucosae of the goose’s small intestine is formed by two layers of unstriated muscle tissue: internal and external. In contradistinction to mammals, the thicker inner layer of the LMM has not a circular, but a longitudinal direction of cell location while by contrast the thinner outer layer is located in a circular direction. According to results of our research, the thickness of the lamina muscularis mucosae of the small intestine of the geese rapidly increased with age. The thickness of the duodenum corresponded to the value of adult geese at 60 days of age; jejunum, ileum, and rectum – at 21 days, cecum – at 7 days age. The lamina muscularis mucosae was thinnest in the duodenum, and it was thickest in the ileum. The lamina muscularis mucosa of the large intestine of geese is represented by only one longitudinal layer. By contrast, the thinner outer layer is located in a circular direction. Detailed information of the microscopic structure of the lamina muscularis mucosae of the intestine of geese can be useful for specialists, both morphologists and physiologists, for analyzing the histological preparations of the intestine of birds by the action of biotic and abiotic factors, as well as a basis of comparison with such structure in other species of animals. The description of the construction of this important microscopic structure of the intestine can serve a morphological basis for elucidating its function.

Для цитаты:Фесенко Ю.А., Холмогорова А.Б. Случаи суицидов среди подростков как социальная про-блема: по следам V всероссийского форума «Наши дети здоровье детей и факторы, его формирующие» // Консультативная психология и психотерапия.

Were investigated microscopical structure features of domestic ducks' (Anas platyrhynchos domesticus) small intestine of the black-white-breasted breed of Ukrainian selection in 9 age groups: 1-, 3-, 7-, 14-, 21-day, 1, 2, 6-month, and 1-year-old. The microstructural morphometric parameters were determined on histological preparations from cross-sections of the intestine's middle part. the surface area was calculated by determining their height and width. The density of villi and crypts was identified based on 1 mm of mucosal length. A common pattern in the dynamics of most morphometric indicators (except for the density of villi and crypt) of the small intestine wall was their increase. Such changes in the size of the intestinal microstructures did not occur simultaneously, they were asynchronous. In some cases, they decreased if compared to a younger age. The most rapid increase in the microstructures of the duodenum, jejunum, and ileum occurred in the first month of the postnatal period of ontogenesis, less intensively in the second month. During the first month, these indicators were changed most rapidly during the first week. They corresponded to the indicators' value of an adult bird at different ages. Thus, the thickness of the muscle layer and density of the duodenal crypts corresponded to the value of adult birds at 21-days-old, the intestine's diameter and wall thickness at 1 month, the mucous layer thickness, the height and density of the villi, and the depth of the crypts at 2-month-old. The wall thickness, mucosal and muscular layers, the height of the jejunal villi corresponded to those in the adult birds of 1-month-old, the diameter of the intestine, the crypts' depth, the density of the villi at 2-month-old, the density of the crypts at 6-month-old. The density of the ileum crypts corresponded to the adult bird at 7-days-old, the intestinal diameter was like at 21-days-old, the depth of the crypts was like at 2-month-old, the density of villi was like at the age of 1-month-old, the intestine wall thickness and muscle layer were like at 6-month-old, the mucous membrane thickness, the height of the villi were like at the age of 1 year.

The aim of the study was to determine the features of the topography and the number of the total population of endocrinocytes and enterochromaffin cells in the intestines of ducks during the first year of the postnatal period of ontogenesis. The experiments were performed on domestic ducks (Anas platyrhynchos domesticus) of black white-breasted breed (n = 5) 9 groups: 1-, 3-, 7-, 14-, 21-days-old, 1-, 2-, 6-month-old and 1-year-old. Determination of the total population of endocrine cells (argyrophilic) and enterochromaffin (argentaffin) was performed on histological specimens made from cross-sections of the middle section of the duodenum, jejunum, ileum, cecum and rectum, stained by Masson and Grimelius. The endocrine cells of 1- and 3-days-old ducks had a «superficial» location due to insufficient formation of crypts and villi. In older birds, in the duodenum, jejunum, and ileum, both argyrophilic and argentaffin APUD cells were localized mainly in crypts, and in the cecum and rectum, they were also in the epithelial layer of the villi. During the entire observation period, the highest content of both argyrophilic and argentaffin endocrinocytes in all intestines were found in 21-days-old ducks. Already at 3-days-old age, the total number of endocrine cells in various intestines corresponded to those of an adult bird. The highest number of argyrophilic and argentaffin endocrinocytes was found in the ileum and cecum, less in the rectum and jejunum, and the smallest number was in the duodenum. Enterochromaffin cells are the most common type of endocrinocytes in the ducks’ intestines, their relative content ranged from 40.1 to 97.5%. The highest relative content of argentaffin cells at 1-, 3- and 7-day-old was observed in the duodenum, at 14-day-old – in the duodenum and colon, at 21-day-old – in the rectum, at 1- and 2-month-old in jejunum, at the age of 6 month – in the duodenum, jejunum and caecum, and at the age of 1-year-old – in the ileum and cecum. In addition to argyrophilic endocrinocytes, which were located in the epithelium, other cells were found in the loose connective tissue of the villi base, the cytoplasm of which was also intensively impregnated with silver nitrate. Such cells were smaller and mostly oval in shape. Their cytoplasm was impregnated almost evenly around the nucleus and had no polarity in the location of the granules. Probably those were mast cells, which also contain bioamines, and, as well as enteroendocrinocytes, are found in the argyrophilic reaction.