DESCRIPTION AND HISTOLOGICAL ANALYSIS OF THE GLANDULA ANNEX TO THE DIGESTIVE SYSTEM OF HOPLIAS MALABARICUS (BLOCH, 1794), (TELEOSTEI, ERYTHRINIDAE)

Abstract

The traíra Hoplias malabaricus is largely distributed in the Uruguay river basin and it is very important for this basin. This work describes and analyses histologically the annexed glands of the digestible tube (liver, biliary vesicle and pancreas), giving support to the alimentary ecology apprehension. Twenty adult specimens, from both sex were collected and immediately fixed in neutral formol at 10% and in Bouin. After making the biometry, the digestible tube was removed through a ventral incision and the glands were isolated. The routine histological technique for optical microscopy was applied by means of transversal sections of the liver and biliary vesicle, including paraffin H-E and Goldner Trichromic, Histoplast with H-E and Toluidin blue. The liver is located before the peritoneal cave and is divided into 3 asymmetric lobos: a right, a left and a smaller transversal one, linking the first two. It is irrigated by hepatic artery and one or more portal veins which drain the gastric and intestinal mucose, the swim bladder, the spleen and the pancreas. The liver is a reticulotubular gland covered by a serous capsule, with cylindrical cells in the mesothelium with a sluggish conjunctive tissue. The hepatocytes are polygonal cells, containing spherical nuclei and presenting usually single nucleus, where inclusions of glycogen and lipids are found. The pancreas is diffused and is present in different liver regions, surrounding big vases hepatopancreas and the mesentery enveloping parts of the posterior intestine. The sacciform biliary vesicle is partially fitted into the liver with a opening duct placed before the posterior intestine. It stores the bile secreted by the liver. It shows the light covered by simple columnar epithelial tissue followed by slack conjunctive tissue, a thin layer of plain muscle covered externally by a serousal layer.