[Comparative anatomo-microscopic observations on the esophagus of teleosts with different feeding habits]

The authors describe the micro-anatomy of the oesophagus of different diet fish: herbivorous (Boops salpa), omnivorous (Liza aurata) and carnivorous fish (Blennius gattorugine and Gaidropsarus mediterraneus). In all the observed species the oesophagus is formed by a tunica mucosa, tunica muscularis and tunica serosa. The tunica mucosa of the herbivorous fish arises to form thin plicae which protrude into the lumen and are covered with squamous stratified epithelium. The goblet cells do not arrange among the covering cells but take place laterally and on the basis of the plicae. The tunica muscularis is constituted by an external circular layer and an inner longitudinal layer of striated muscle. The oesophagus of omnivorous fish shows thick plicae covered with a higher epithelium than that of the herbivorous fish. Among the epithelial cells a lot of taste buds have been found. The tunica muscularis is like that of the herbivorous fish. In the carnivorous fish Blennius the tunica mucosa presents thin plicae like those of the herbivorous fish but they are covered with a thicker epithelium. The tunica muscularis is formed by an external circular layer and by an inner longitudinal layer which constitutes two diametrically opposed bundles placed dorsally and ventrally. In the other carnivorous fish Gaidropsarus, the tunica mucosa shows very thick plicae covered with a quite high squamous epithelium among which there are many goblet cells. In this fish too numerous taste buds have been found. The tunica muscularis is arranged in the same manner observed in the other carnivorous fish.