Histological study of pylorus in two month old Caspian Sea beluga (Huso huso Linnaeus, 1758)

Regarding the role of alimentary tract in digestion and absorption of foods in fish andimportance of Huso huso due to caviar production, this study was carried out onpylorus or non glandular stomach in two month old Beluga with aiming to determineits precise histologic structures. The fish samples were prepared from sturgeonartificial rearing stations in Saari and fixed into 10% formalin. The histologicalsections with 6 microns were prepared based on routine histological process. Thehematoxylin and eosin method was used for staining of sections and studied underlight microscope. The results showed that pylorus or gizzard as non glandularstomach has a mucosa lined with non ciliated simple columnar epithelium. Theircytoplasm is highly acidophilic with a dark basophilic nucleus. In lamina propria withloose connective tissue some rare simple tubular glands are appearing in this agedespite of absence of any gastric glands. Smooth muscle fibers as muscularis mucosadifferentiate mucosa from submucosa. The submucosa is thin without any glands andthe thick musculature in several layers thicker than the other parts, is surrounded withsquamous cells externally as serosa. Locating the pylorus in continuation of glandularstomach and the thick musculature more than its digestive role indicates itsmechanical role in crushing the foods.

Keywords:

Beluga , Pylorus , Histology