This study investigates the stomach morphology and histochemistry of Clarias gariepinus. Grossly, the stomach is a J-shaped organ with three distinct regions: cardiac, fundic, and pyloric. Histologically, its wall comprises four layers: mucosa, submucosa, muscularis externa, and serosa. The mucosa exhibits broad longitudinal folds lined by high columnar cells with basal oval nuclei. These cells contain apical mucosubstances that react positively with Periodic Acid Schiff (PAS) stain and negatively with Alcian Blue (AB). Gastric pits result from mucosal invaginations. Glands are present in the fundic and cardiac regions but absent in the pyloric. Oxynticopeptic cells exclusively line the fundic glands. Enteroendocrine cells are distributed throughout the gastric wall, appearing within the epithelial layer and mucosal glands. The lamina propria comprises collagen fibers, blood vessels, and nerves, separated from the submucosa by smooth muscle strands forming the lamina muscularis mucosa. The submucosa consists of loose connective tissue. The pyloric region contains the thickest muscularis, composed of thin inner and outer longitudinal layers flanking a substantial middle circular layer of smooth muscle fibers (SMF). The serosal coat of the stomach is a thin layer of loose connective tissue embedded with blood vessels, covered externally by a single layer of mesothelial cells. These findings indicate that Clarias gariepinus exhibits gastric characteristics aligned with carnivorous feeding.
