Comparative histological and ultrastructural studies on the liver and pancreas of Schilbe mystus and Labeo niloticus

Abstract

ABSTRACThe present investigation aims to illustrate the histological and ultrastructural differences of the liver and pancreas of a carnivorous fish, Schilbe mystus, and a herbivorous fish, Labeo niloticus. The histological examination of the liver of both studied species revealed that the liver is mainly composed of a continuous compact field of the hepatocytes. The hepatocyte-sinusoidal structure of the liver of Schilbe mystus consists of the solid form and tubular one, while that of Labeo niloticus consists of the tubular form and cord-like one.The ultrastructural examination of the liver of both studied species revealed that it is composed mainly of hepatocytes, Kupffer (macrophages) and to (fat-storing) cells. The hepatocytes of Schilbe mystus are characterized by the presence of numerous glycogen rosettes, numerous lipid droplets and a rough endoplasmic reticulum, while those of Labeo niloticus are characterized by the presence of numerous glycogen rosettes, a few lipid droplets and a rough endoplasmic reticulum. The hepatocytes of both studied species possess numerous microvilli, which extend into the space of Disse or into the bile canaliculi lumina.In both studied species, there is a prominent perisinusoidal space between the hepatocytes and blood sinusoids, the space of Disse. This space usually contains the Ito cells, which are stellate in shape and are characterized by the presence of lipid droplets.The bile canaliculi of Schilbe mystus are of the intercellular type, while those of Labeo niloticus are of both the intercellular and intracellular types.The histological investigation of the pancreas of both studied species revealed that there are three types: the compact, disseminated and intrahepatic types. This pancreas showed that it consists of a highly lobulated gland of the compound acinar type. The acinar (pancreatic) cells are pyramidal in shape; they possess a basophilic cytoplasm and eosinophilic zymogenous secretory granules.The ultrastructural investigation of the acinar cells of both studied species revealed two cell types: the dark and light acinar cells. These cells are characterized by the presence of numerous zymogenous secretory granules and a well-developed rough endoplasmic reticulum.

Ultrastructure of the digestive tract in neotropical carnivorous catfish Hemisorubim platyrhynchos (Valenciennes, 1840) (Siluriformes, Pimelodidae)

“…According to Naguib et al . (), the granules of epithelial cells of the stomach of Schilbe mystus appear frequently in contact with the apical plasma membrane to empty its contents into the gastric lumen. These granules are secreted into the gastric lumen by exocytosis (Noaillac‐Depeyre and Gas, ; Ostos‐Garrido et al ., ) and they protect the epithelium of stomach from autodigestion processes caused by secretions produced in the gastric glands (Ferraris et al ., ).…”

Ultrastructural studies of Puntius shalynius an endemic and threatened hill stream fish

“…(Athikesavan et al, 2006). Similar o b s e r v a t i o n s w e r e r e p o r t e d i n t h e i n t e s t i n e o f Hypophthalmichthys molitrix and Labeo niloticus (Naguib et al, 2011). The apical cytoplasm just below the microvilli had no cellular organelles and formed the terminal web.…”

Descripción Morfológica e Histológica del Tejido Hepático de Gambusia holbrooki (Pisce: Poeciliidae) que Habita en la Provincia de Arica - Chile

“…El hígado de Gambusia holbrooki está ordenada por medio de trabéculas hepáticas intercaladas con sinusoides, coincidentes con otras especies Gnathonemus petersii, Rutilus rutilus y Syprinus carpio (Genten et al), mientras que la morfología poliédrica de los hepatocitos con núcleo central y nucléolo vistoso es común a muchas especies de teleósteos, por ejemplo Oreochromis niloticus (Torres et al, 2010), Paralabrax maculatofasciatus (Zacarias et al), Schilbe mytus, Labeo niloticus (Naguid et al, 2009) y Scatophagus argus (Morovvati et al, 2012). Estas coincidencias morfológicas en especies tan distintas filogenéticamente, permite sostener que la morfología hepática se perpetua con la función, posibilitando diferenciar estructuras histológicas para estudios biométricos utilizando unidades como el tamaño y número de los hepatocitos o variación en la irrigación sanguínea del hígado.…”