Siberian sturgeon (Acipenser baeri, Brandt JF 1869) gut: anatomic description.

Efforts to refine rations for captive rearing are dependent on a clear understanding of gut anatomy and function. Gross anatomic and histological descriptions of the gut of the Siberian sturgeon Acipenser baeri, are provided in this manuscript to serve as a baseline characterization for comparison during basic research and health surveys of Siberian sturgeon populations. Histological evaluations were carried out on 200 individuals (body weight ranging from 50 to 8000 g), using gross anatomy and light microscopy. The most characteristic finding is about pancreas, which has three distinct lobes. The pancreatic duct ends in a papilla between the small intestine and the pyloric caecum. Eosinophilic zymogen granules characterize exocrine cells, and the endocrine cells are grouped together in structures that are similar to mammalian Islets of Langerhans with not homogeneous distribution. Morphometrical evaluation shows that the mean area of the islets is 8.32 mm2×10-3. The Siberian sturgeon pancreas is a morphologically distinct organ functionally and histologically similar to that of mammals.