Histological variations and adaptability in some digestive organs of the thinlip grey mullet, Chelon ramada (Risso, 1827)

Abstract

The objective of the present study was to explain the histological variations in the pyloric caeca and anterior intestine of Chelonramada.For this purpose, small pieces of the target organs were attained from specimens ofC.ramada: for histological and histochemical procedures. The final sections were examined under a microscope, photographed and described. Histologically, serosa, muscularis, submucosa, and mucosae are the main layers of the wall of pyloric caeca and anterior intestine in C.ramada indicating there are no remarkable differences in the basic structure. The mucosal folds of pyloric caeca are thin and deeply folded in a narrow lumen; in contrast, the mucosal folds of the anterior intestine are long protruding at a wide lumen. The mucosal layer of the anterior intestine is consisted of columnar and mucus cells as in the pyloric caeca, but mucous cells are numerous in number at the anterior intestine while it observed in fewer numbers at the mucosal layer of the pyloric caeca. In submucosal and mucosal layers, wandering cells and lymphocytes are plentiful especially among the columnar cells of the anterior intestine. These cells are more abundant in the anterior intestine than that observed in pyloric caeca; in contrast with the number of blood vessels. The present study concluded that the distribution and secretions of the mucosa are very clear with histochemical stains. This study is helpful for understanding the digestive physiology and the related functional mechanisms of fish digestion.