中华刺鳅消化系统形态与组织学研究

应用活体解剖和光镜技术对中华刺鳅消化系统形态与组织学特征进行了研究。结果显示:中华刺鳅属典型的无鳔管、有胃鱼类，消化道较短，约为体长的45%，整体呈“Z”字形。食道很短，后与胃相联，胃呈“V”型，胃分为贲门部、胃底部和幽门部，贲门胃自食道末端到胃的底部都具有丰富的腺组织分布，其长度也是胃部最长的，约占中华刺鳅消化管长度的23%。胃底部的肌肉发达较厚，但仅贲门部有丰富的腺组织。消化道各段在组织结构上差异显著。胃前，消化道肌肉层内环肌与外纵肌厚度之比自前向后逐渐增大，杯状细胞数量自前向后逐渐减少；胃后，肠道肌肉层内环肌与外纵肌厚度之比则逐渐减小，杯状细胞数量逐渐增多。消化腺分为肝脏和胰腺，肝脏与胰脏为独立的两个器官，胰脏分散分布于胃与肠道周围的系膜内，肉眼可见。未发现类似鲤科鱼类弥撒于肝脏或脾脏内的胰腺结构。中华刺鳅以日本沼虾和秀丽白虾为主要摄食对象，性凶猛，为典型的肉食性鱼类。

MORPHOLOGICAL AND HISTOLOGICAL CHARACTERIZATION OF THE DIGESTIVE SYSTEM OFSINOBDELLA SINENSIS BLEEKER, 1870

Sinobdella sinensis Bleeker1870 widely distributes in the subtrophic freshwater of China and Vietnam, however, the morphology and histology of the digestive system ofS. sinensis have not been reported yet. In the present study, morphological and histological characteristics of the digestive system ofS. sinensis were studied by vivisection and histological observation. The results showed thatS. sinensis has a stomach but no pneumatic duct. The digestive tract is short and about 45% of the body length with a “Z”-shape. The esophagus is short and connected to the stomach which constitutes cardiac fundus and pyloricus parts. The glandular tissue is abundantly distributed from the end of eso-phagus to the fundus of stomach. The cardiac stomach occupies 23% of the whole stomach in length. However, abun-dant glandular tissues are only distributed in the cardiac part of esophagus. The structure of each part of the digestive tract is significantly differenct. In anterior gastric part, the ratio of gastrointestinal internal-circular muscle layer to ex-ternal-longitudinal muscle layer gradually increased and the number of goblet cells decreased and completely opposite observations occurd in posterior gastric part. The digestive glands included liver and pancreas, but no diffused pancreas tissue occurred in liver or spleen, like other Cyprinidae fish. Therefore, our results indicated thatSinobdella sinensis is a typical carnivorous fish and prey onMacrobranchium nipponense andExopalaemon modestus as the main food.