Histological and histochemical study on the large intestine of one-humped camel in Iraq

The aim of the study was to investigate the histological aspects of the large intestine of adult one-humped camels (Camelus dromedarius) domiciled in Iraq. To conduct that, large intestines samples of twelve adult camels (six males and six females) obtained directly after animals slaughtering. Tissue specimens from different segments of the intestine (cecum, colon, and rectum) were collected, fixed, processed routinely, and subsequently stained with H&E, Lillies Allochrome, Periodic Acid Schiff, Combined AB–PAS, and Gomori Aldehyde-Fuchsin stains. The microscopic examination showed the composition of tunica mucosa, submucosa, muscularis, and serosa layers. Lining epithelium of all segments showed their consistency of simple columnar and goblet cells. Distinctly, the muscularis mucosa separates mucosa from submucosa layers. Tunica muscularis structured of two distinct layers (inner circular and outer longitudinal); the outer layer is organized by three separated bands, that is known as taeniae coli. The histochemically stained sections revealed scattered goblet cells of all segments that were strongly reacted to PAS. Staining with PAS-AB showed negative or faintly bluish stained epithelial cells due to the reaction with AB contents, whereas goblet cells showed toughly positive reaction due to the PAS contents. The gomori Aldehyde-Fuchsin stain showed goblet cells strongly reacted to the acidic, non-sulfated, mucopolysaccharides but columnar epithelium were showing poor reaction toward this stain. the unique structure of large intestine of one-humped camels has investigated and its composed layers have remarkably observed in this work.