Histological and ultrastructural study of intestine of Asiatic knife fish, Notopterus notopterus

The purpose of the present study was to study the histological and ultrastructural description of the intestine of the teleost fish Notopterus notopterus. Knowledge about morphology, histology and ultrastructural studies is essential for deeper understanding of the physiology and pathology of fish intestine. The intestinal morphology of the fish can be influenced by feeding habits. Notopterus notopterus, a carnivorous fish, shows typical intestinal morphology. Interestingly the intestine of the fish is very short. Histologically, the intestinal wall of the investigated species comprised of mucosa, sub-mucosa, muscularis and serosa. Stratum compactum and stratum granulosum layers found in the sub mucosa. Numerous villi lined with simple columnar epithelium along with absorptive cells, intraepithelial lymphocytes and goblet cells were observed which were numerous in the proximal region of intestine as compared to distal region of intestine of N. notopterus. Eosinophilic granular cells (paneth cell) which show a protective role in fish immunity were observed in the mucosa, sub-mucosa and lamina propria of intestine. Ultrastructural studies of intestine showed the presence of enterocytes with regular microvilli, junctional complex, lysosomes, endoplasmic reticulum, microfilaments and polymorphic mitochondria.