Comparative Histomorphological Studies on Oesophagus of Catfish and Grass Carp

The present work was carried out on 40 specimens of oesophaguses of both sexes of catfish (carnivorous fish) and grass carp (herbivorous fish) in order to observe the morphological and histological differences between the two species. Oesophagus of catfish was divided into 2 parts: anterior and posterior ones. The anterior part of the oesophagus of catfish was characterized by the presence of numerous mucosal folds. It was lined by stratified epithelium with goblet cells. In addition to club cells were observed in between the stratified epithelium. Scanning electron examination of the oesophageal epithelium of catfish demonstrated the presence of microvilli and fingerprint-like microridges in the superficial cell layer. The posterior part of the oesophagus of catfish was characterized by simple columnar mucus-secreting epithelium. The oesophagus of grass carp had shown the same structure along its entire length. It consisted of less folded mucosa than that observed in the oesophagus of catfish. The epithelium was characterized by the presence of taste buds. In conclusion, the present work revealed some differences in the structure of catfish oesophagus and grass carp oesophagus. These differences are related to type of food and feeding habits of each species