Anderson Trevor A
School of Biological Sciences, University of Sydney, Sydney 2006, Australia.
J Morphol. 1986 Oct;190(1):109-119. doi: 10.1002/jmor.1051900110.
The gastrointestinal tract of Girella tricuspidata, an herbivorous teleost, is differentiated into esophagus, stomach, pyloric caeca, intestine, and rectum. The mucosa of the esophagus consists almost entirely of elongated secretory cells, with an underlying submucosa and prominent circular and longitudinal muscle layers. The anterior part of the stomach contains a mucous surface epithelium and a network of tubular glands having only one type of glandular cell, to which secretion of both pepsinogen and HCl is attributed. The tubular glands are not present in the pyloric region. The gastric wall contains well developed circular muscle and submucosal layers. The pyloric caeca contain a mucosa containing two types of exocrine cells. The nature and function of secretions from these cells is discussed. The intestinal mucosa is differentiated into an anterior (ca. 30%) and a posterior section. The enterocytes of the anterior portion show evidence of lipid absorption, while those of the posterior intestine and rectum show considerable pinocytotic activity. The pyloric caeca, intestine, and rectum have a layer of submucosa and a thin layer of circular muscle. The presence of the prominent circular muscle in both the esophagus and the stomach is postulated to be advantageous to an herbivorous fish. However, other ultrastructural features of the gastrointestinal tract of the luderick are similar to those described in carnivorous fish and appear to show no specialization for herbivory.
三齿鲀，一种草食性硬骨鱼，其胃肠道分为食道、胃、幽门盲囊、肠和直肠。食道黏膜几乎完全由细长的分泌细胞组成，下方有黏膜下层以及明显的环形和纵形肌层。胃的前部有黏液表面上皮和仅含一种腺细胞的管状腺网络，胃蛋白酶原和盐酸的分泌都归因于这种腺细胞。幽门区域没有管状腺。胃壁有发育良好的环形肌层和黏膜下层。幽门盲囊的黏膜含有两种外分泌细胞。文中讨论了这些细胞分泌物的性质和功能。肠黏膜分为前部（约占30%）和后部。前部的肠上皮细胞有脂质吸收的迹象，而后肠和直肠的肠上皮细胞有相当活跃的胞饮作用。幽门盲囊、肠和直肠有一层黏膜下层和一层薄的环形肌。推测食道和胃中明显的环形肌对草食性鱼类有利。然而，绿鳍鱼胃肠道的其他超微结构特征与肉食性鱼类中描述的相似，似乎没有表现出对草食性的特殊适应性。
