Effects of Starvation on Histological Structure of Digestive Tract of Paralichthys lethostigma

The techniques of anatomy, paraffin section and photomicrography were used in this paper. Histological structure of the digestive tract of Paralichthys lethostigma and histological changes including thickness of striated border, height of columnar cell, thickness of wall and muscle layer in digestive tract as well as the size of mucous cell in esophagus and intestine following starvation for 10 days were assessed by light microscopy. The results show that the digestive tract of Paralichthys lethostigma consisted of mucosa, submucosa, muscles and serosa layer. The mucosal epithelium of the esophagus was stratified squamous epithelium, while epithelium in stomach and intestine's was simple columnar epithelium, and it was pseudostratified ciliated columnar epithelium in rectum. Goblet cells existed between the epithelial cells in digestive tract except stomach. Submucosa layers were loose connective tissue. The muscle of esophagus was striated muscle arranged in the inner longitudinal and outer circular. However, in other segments of digestive tract, the muscle was composed of smooth muscle cells and the cells arrangement patterns were opposite to that of esophagus musclar layer. Starvation for 10 days resulted in the decrease of height of mucosa rugae, disruption and exfoliation of the striated border, and the connection between the size of goblet cells significantly reduced. The height of columnar cells in stomach, intestine and rectum, as well as the thickness of muscle layer and the wall of foregut and midgut significantly decreased. This study provided scientific data for understanding Paralichthys lethostigma to the starvation tolerance and artificial culture of the fish.