A comparative histological and histochemical study of colon in goat (Capra hircus) and sheep Ovis aries

Abstract

This study aimed to comparative the histomorphometry structure of colon in sheep and goat. Seven samples from each animal, the specimens for histological and histochemical study were taken from different regions from each of the portion of colon (ascending, descending and transverse). The colon wall was composed of four tunicae; mucosa, submucosa, muscularis and serosa. The mucosa showed three different layers; the lining epithelium, the muscularis mucosa, and the lamina propria containing Lieberkühn crypts. The epithelium lined the mucosal folds and was composed of simple columnar epithelia with goblet cells. Goblet cells had been globular-shaped, unorganized mucus which were dispersed among the rows of epithelium cells and Lieberkühn crypts. The colon's mucosa was identified by the presence of long-shaped folds that were grouped in a zigzag arrangement in sheep and leaf-shape mucosal folds make up the mucosal surface in goats. Sheep have simpler, tubular, straight, unbranched glands in their colon epithelium than goats. Goats have intestinal glands at the lamina muscularis, while sheep have aggregated lymphatic nodules near the lamina muscularis. The goblet cells in the lining epithelium with Lieberkühn crypts of goat and sheep had robust positive reactions to both periodic acid Schiff stain and Alcian blue, whereas all research animals showed negative reactions with Alcian blue. The submucosa is made up of dense, connective tissue that contains nerves and blood vessels. The muscularis externia was made up of inner circular layer and outer longitudinal layer. In certain colon locations, the outer layer's smooth muscle layers had non-continuous, altered thickenings that were primarily localized into three flat bands, or taeniae coli. In sheep, the tunica serosa was made up of collagen and elastic fibers; in goats consists of only collagen fibers, the adventitia; loose connective tissue in certain areas of the colon of goat and sheep. These tunicae were thicker in sheep colon than in goat colon. Conclusions: Animals undergo several modifications as a result of evolution in order to adapt to their surroundings. Every species has distinct characteristics that aid in their survival and allow them to eat a variety of foods.