The Histological and Histochemical study on the esophagus and intestine in common carp fish(Cyprinus carpio Linnaeus(1758))

Ten common carp fish weighing 500-600 g and 28-30 cm in length, comprising both sexes, were collected from fish culture ponds, around Ardebil city. Dewaxed sections (5-6 μm) were stained for histological and histochemical purposes with haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and Alcian blue. The histological and histochemical characteristics of the esophagus and intestine were studied by the use of a light microscope. The gastrointestinal tract of the common carpwas divided into an esophagus and intestine. The esophagus was short, with longitudinal mucosal folds but The intestine have shorter mucosal folds in than the esophagus folds and a thinner wall in comparison with esophagus. The histological structure was divided in four layers: mucosa, submucosa, muscular, and serosa. Intestinal mucosa displayed many simple columnar epithelium in associated with goblet cells and intraepithelial lymphocytes. Histochemical analysis showed that the goblet cells have acidic and neutral mucosubstances.