The morphology and histology of digestive system of Coilia nasus were studied using light microscopy and scanning electron microscopy. The digestive tract could be divided into the buccal-pharynx cavity, esophagus, stomach, intestine and anal portions. The specimen examined had a big mouth crack, canine-shaped jaw teeth, cone-shaped palatal teeth, but no pharyngeal teeth were observed. The specimen contained 5 pairs gill arch, and the length of gill raker whose surface being coated with irregular small tooth was greater than that of gill filament. The shape of stomach was like a "Y". 16 -21 multi-finger pyloric caeca were observed in conjunctive site of the stomach and intestine. The intestine was short and rectum. The ratio of intestine length to body length was 0. 241 ±0. 080. Liver was divided into two parts. Histological studies showed that the wall of digestive tract was composed of mucosa, submucosa, muscle layer, and serosa layers. The mucosa epithelium of the buccal-pharynx cavity of this species was stratified squamous, with abundant rounded mucous cells. The taste buds, glands, and goblet cells were observed in the oral cavity. Mucosa epithelium of stomach was simple columnar, and well-developed gastric glands and gastric pits were present in the stomach. The pyloric caeca mucosa had about 20 - 25 wrinkles covered with microvilla, and these wrinkles filled in most part of the pyloric caeca cavity. The three portions of the intestine showed histological differences. Mucous epithelium of intermediate intestine was well developed, and both stratified squamous epithelium and simple columnar epithelium were observed. Mucosal foldings were slender and linked into a mesh. The results suggest that the digesting system of C. Nasus shows typical characteristics of carnivorous fish.
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维普
万方数据
