Comparative characterization of the ultrastructure of intestinal epithelium of various sturgeon species

The ultrastructure of the mid-intestine of four sturgeon species and their hybrids was studied. Apart from enterocytes and glandular goblet cells, the cells with microvilli, endocrine cells, and immunocompetent elements were revealed. Specific cells responsible for the primary immune response, analogous to mammalian M-cells, were discovered in sturgeon fishes. The ultrastructural characteristics common for the mid-intestinal epithelium of all the sturgeon fishes studied were determined. Species-specific features of intestinal epithelium of the parent species, which were characteristic of the hybrids, were revealed.