Histological Structure and Histochemistry of the Digestive Tract of the Striped Tiger Nandid Fish, Pristolepis fasciata

Abstract

The striped tiger nandid fish, Pristolepis fasciata, is widely distributed in Thailand. However, its diet composition has been intensively investigated. The histological profile remains an exciting and challenging issue. Therefore, the objectives of this study are to describe the histological structure and histochemistry of the digestive tract of the striped tiger nandid fish. Fifteen adult fish were collected from Songkhla province, Thailand. The digestive tract was fixed in Bouin’s solution, followed by basic paraffin techniques. The 5 µm sections were stained with hematoxylin and eosin (H&E), periodic acid Schiff’s (PAS), alcian blue (AB) pH 2.5 and pH 1.0, and Masson's trichrome (MT). The results revealed that the digestive tract wall comprised four layers: mucosa, submucosa, muscularis, and serosa. The mucous and goblet cells in the esophagus exhibited positive staining with PAS, AB pH 2.5, and pH 1.0. The stomach was divided into three parts: cardiac, fundic, and pyloric stomach. The epithelium of the cardiac stomach showed positive staining with PAS and weak staining with AB pH 1.0. The fundic cells showed strong positive staining with PAS but weak staining with AB pH 2.5 and 1.0. In contrast, the cells lining the fundic and cardiac glands showed positive staining with PAS. The pyloric epithelium revealed positive staining with PAS but did not contain a gland. In the anterior, middle, and posterior intestines, glands were absent. Goblet cells exhibited intense labeling with PAS and AB pH 2.5 and 1.0 in each portion. The intestinal coefficient was 0.62±0.01, indicating an omnivorous fish.