银鲳(Pampus argenteus)幼鱼饥饿前后侧囊及肝脏超微结构的变化

THE DIFFERENCE IN ULTRASTRUCTURE CHANGES OF ESOPHAGEAL SAC AND LIVER IN NORMAL AND HUNGER JUVENILE OF PAMPUS ARGENTEUS

分别采用扫描和透射电镜,观察了正常和饥饿5d银鲳(Pampus argenteus)幼鱼的食道侧囊及肝脏超微结构的变化。结果表明,正常银鲳幼鱼侧囊内壁具有许多平均高度为800 m的乳突,上有次级突起。乳突黏膜由复层扁平上皮构成,上皮细胞表面有指纹状的微嵴,有缓解上皮细胞的机械损伤作用;银鲳肝脏具肝血窦、胆小管、狄氏窦等结构,肝细胞排列较紧密,内含丰富的细胞器和脂滴,核仁大而明显,线粒体数目多,多分布在细胞核、内质网和狄氏窦周围。饥饿后,侧囊乳突变低矮,平均高度700 m,乳突上黏膜变薄,逐渐退缩,次级突起顶端露出了尖刺状的角质刺;肝细胞体积缩小,核变小,细胞器数目减少,线粒体水肿,粗面内质网数量显著降低,脂滴数量降低,这是银鲳幼鱼对饥饿的生理性防御。

he differences in ultrastructure changes of esophageal sac and liver in normal and 5d hunger juvenile of Pampus argenteus was observed in scanning and transmission electron microscopy. Result showsa number of mastoids in average height of 800μm in the inner wall of esophageal sac, on which the secondary mastoids were found in normal juvenile of P. argenteus. Mastoid mucosa consisted of a stratified squamous epithelium, with fingerprint-like microridges at the surface of epithelial cellsfor playing a role of mitigation to mechanical damage of epithelial cells. The liver cells of normal fish show textures of hepatic sinus, erythrocytes, microvilli, Dieldrin sinus, bile canaliculi, and mitochondria , Hepatic cell arranged closely, containing many organelles and lipid droplets, nucleoli were large and obvious. Many mitochondria located around the nucleus, endoplasmic reticulum, and Dieldrin sinus. After starvation, the mastoids in the inner wall of esophageal sac became lowered （average height 700μm）, mastoid mucosa thinned and retreated gradually, during which sharp horny spine was exposed from the top of secondary mastoid. The structure of liver cells changed greatly after starvation： sizes of liver cells and nuclear shrank, the number of organelles reduced, mitochondria swelled, the number of rough endoplasmic reticulum and lipid droplets decreased significantly, which is a physiological defense against starvation by juvenile of P. argenteus.