马苏大麻哈鱼幼鱼消化系统形态学和组织学观察

Morphology and Histology of Digestive System in Juvenile Masu Salmon Oncorhynchus masou

采用解剖学和光学显微镜技术研究叉长(9.70±0.53)cm、体质量(11.30±0.86)g的马苏大麻哈鱼Oncorhynchus masou幼鱼消化系统的形态及组织结构特征。结果显示:马苏大麻哈鱼的消化系统由口咽腔、食道、胃、幽门盲囊、肠道和肝脏等组成,其口裂较大、咽骨齿明显;食道短而粗,具有较厚的肌肉层和黏膜褶皱;胃由贲门部、胃体部、盲囊部及幽门盲囊组成,其中胃体部肌肉层较厚,黏膜层褶皱分支多,明显高于贲门部和幽门部,为食物主要消化吸收场所,而幽门盲囊呈圆柱棒状,内部具有7~11个排列疏松的黏膜褶皱;肠道前端含有少量幽门盲囊,后端平直无弯曲,黏膜上层单层柱状细胞间隙中分布大量杯状细胞;肝脏不分叶,肝小叶界限不明显,但其含有丰富的中央静脉和胆管。马苏大麻哈鱼的消化道和消化腺具有典型肉食性鱼类消化系统的特征。

The morphology and tissue structure of digestive system in juvenile masu salmon(Oncorhynchus masou)were observed by the anatomical and light microscopy techniques.The results showed that the digestive system of masu salmon was composed of buccal-pharynx cavity,esophagus,stomach,intestine and liver,with large cleft and obvious pharyngeal bone teeth.The juvenile masu salmon had a very coarse and short esophagus with thick muscle layer and mucosal folds.The stomach was composed of cardiac stomach,fundic stomach,pyloric stomach and pyloric caecum,and the muscular layer of the fundic stomach was thick and the folds of the mucosal layer had many folds and branches which is the main site for food digestion and absorption,significantly higher than that in the cardiac stomach and pyloric stomach.The pyloric caecum was a cylindrical rod in shape,and 7~11 loosely arranged mucosal folds were distributed inside.There was a small amount of pyloric caeca anterior to the intestine,and without bending in the rear end.Moreover,a large number of goblet cells were distributed in the gap between the monolayer columnar cells of the intestine.The liver was not divided into lobes,and the boundaries of liver lobule were not obvious,rich in central veins and bile ducts.The findings indicate that gastrointestinal tract and digestive glands of masu salmon are characterized by the digestive system of carnivorous fish.