Microscopic structure of the rectum of the domestic duck

Abstract

As a rule, researchers pay less attention to the features of the large intestine than to the small intestine. The purpose of the study was to determine the features of the microscopic structure of the rectum of ducks during the first year of the postnatal period of ontogenesis. For histological examinations, the material was selected from Ukrainian white-breasted ducks of 9 age groups: 1-, 3-, 7-, 14-, 21-day-old, 1-, 2-, 6-month-old and 1-year-old. Morphometric parameters of microstructures were set on cross sections of the midgut. The general change pattern in the morphometric parameters of the microstructures of the rectum of ducks was their increase, which was asynchronous and uneven. There was observed an active intestinal morphogenesis continued, as evidenced by the process of formation of villi and crypts in the group of 1-3-day-old ducks. The most intensive morphometric parameters of the rectum changed in the first month of the postnatal period of ontogenesis, during which – in the first week. In the first week, first and second month of life of ducks, the wall thickness of the rectum increased by 93.1, respectively; 199.5 and 20.4 %, the thickness of the mucous membrane – 81.0; 167.1 and 19.5 %, the thickness of the muscular membrane – by 126.1; 285.3 and 22.7 %, the height of the villi – by 113.2; 208.7 and 7.2 %, the width of the villi – by 84.7; 70.9 and 12.5 %, their surface area – by 293.8; 427.6 and 20.6 %, the depth of the crypt – by 85.1; 49.9 and 52.3 %, muscle plate thickness – by 254.0; 750.8 and 15.0 %. The most stable indicators of the rectum during the first year of the postnatal period of ontogenesis were the density of villi and crypts, the number of which after 7 days of age had no significant difference compared to that of a younger age. The indicates of adult birds morphometric parameters of the rectum of ducks corresponded at different ages: in 1-year-old – the thickness of the serous membrane and the density of villi; at 6 months – the diameter of the intestine, the surface area of the villi; at 2 months of age – the thickness of the wall and its mucous membrane, the width of the villi, the depth of the crypt; at 1 month – the thickness of the muscular membrane and plate, the height of the villi, the epithelium of the villi and crypt; at 3 days of age – the density of crypts; at 1 day of age – the width of the crypt.