Microanatomy and Histochemistry of Esophagus and Gastrointestinal Organ of the Spotted Scat, Scatophagus argus during Juvenile Stage from Pranburi Estuary, Thailand

Abstract

The purpose of this research was to study the histological structure and histochemistry of esophagus and gastrointestinal organ of the spotted scat, Scatophagus argus inhabiting the Pranburi estuary, Prachuap Khiri Khan province. All fish were caught by using a gill net. Ten fish (about 5.06 cm. in body length) were randomly chosen as samples for this study. Afterwards, the fish specimens were processed by the standard histological technique and examined under a light microscope. The results revealed that the digestive tract staring from esophagus, stomach and intestine of this fish species comprised of four layers; mucosa, submucosa, muscularis and serosa, respectively. Herein, the character of mucosa in each organ was longitudinal fold protruding into the lumen and can be divided into three sub-layers including epithelium, lamina propria and muscularis mucosae. For the mucosal epithelium of esophagus, it was simple squamous epithelium. On the contrary, other regions were covered by simple columnar epithelia. Moreover, gastric gland was mainly found throughout its stomach in the lamina propria. Based on histochemical study, it was found that the gastric gland was positively stained with Periodic Acid Schiff (PAS) (magenta) whereas was negatively stained with Alcian Blue (AB) pH 2.5. However, the goblet and mucous cells positively stained with both PAS (magenta) and AB pH 2.5 (blue). The current study provides the basic information about structural histology of different organs in alimentary canal but fine descriptive investigation has to be further required.