Histological aspects of the intestinal tract of lambaris (astyanax altiparanae: characidae) produced in captivity

Studies that address the morphology of the intestinal tract of fish have expanded the knowledge about the biology and nutritional management of native fish. The objective of this work was to describe some histological and histochemicalaspects of the intestinal tract of the yellow-tailed lambari (Astiyanax altiparanae - Charicidae) raised in captivity. The specimens obtained from the Grupo Acorci were immediately necropsied and the intestines were fixedin 10% formol. The fragments were subjected to automated processing, cut in a microtome at 4-µm thickness, and stained by Mallory's Trichrome, Hematoxylin and Eosin, Alcian Blue and Schiff's Periodic Acid (PAS). The histological study revealed three tunics: mucous, muscular and serous.The mucosa layer was consisted by a simple prismatic epithelium with basal nucleus and goblets cells PAS and AB positive, enterocytes and lamina propria with loose connective tissue and with nomucous muscle layer. The muscular tunic presented two muscular layers, internal and external, increasing the thickness in the cranio-caudal direction. Villi were morphologically differentin terms of height, thickness of branches, cell types and the presence of mucosal-associated intraepithelial lymphocytes.This study generated information on some histological particularities in the intestine of Astyanax, contributing to the improvement of nutritional management in captive.