军曹鱼消化系统的形态及组织学研究

Morphological and histological observations of digestive system of cobia Rachycentron canadum

利用活体解剖和光镜技术对军曹鱼Rachycentron canadum消化系统进行形态及组织学研究。结果显示,军曹鱼消化道由口咽腔、食道、胃、幽门盲囊、前肠、中肠和后肠几部分组成。口咽腔大,粘膜上皮为复层鳞状上皮,内含少量杯状细胞。食道很短,但上皮包括复层鳞状上皮区和单层柱状上皮区。胃膨大,呈Y形,在贲门和幽门部可观测到杯状细胞,胃体粘膜层下有大量的胃腺细胞。幽门盲囊发达,肠短但分3部分,前肠、中肠和后肠,肠道系数为0.43,肠道由前向后杯状细胞和粘膜皱褶不断减少。消化腺包括肝脏和胰腺,肝小叶分界不明显,肝细胞内脂肪含量丰富,胰腺属于散在性的,其外分泌部有许多腺泡组成,胰岛分散于外分泌部间。

The morphology and histology of the digestive system of Rachycentron canadum was studied using anatomy and light microscope. The results showed that the digestive tract in R. canadum was consisted of buccal-pharynx cavity, esophagus, stomach, pyloric caeca, foregut, midgut and hindgut. The buccal-pharynx cavity was large, and its mucosa was composed of stratified squamous epitheliums with a few goblet cells. The oesophagus was very short, and stratified and simple columnar squamous epitheliums were identified. The stomach was expanded and Y-shaped and many goblet cells were observed in the epitheliums of cardiac stomach and pyloric stom- ach. Many gastric glands cells were found under the mucosa of the stomach. The pyloric caeca were very developed, and the intestines was short and divided into three parts ： foregut, midgut and hindgut. The average intestinal coefficient of R. canadum was calculated, which was about 0. 43. From foregut to hindgut, the number of goblet cells and intestinal villus reduced gradually. The digestive glands were composed of liver and pancreas. The liver lobule was not clear but its hepatic cells were rich in fat. Pancreas was diffused and the exocrine section of pancreas was consisted of many pancreatic aeinar ceils. The pancreas islets were located in the exocrine section.