Histochemical differentiation of glycoconjugates occurring in the tilapine intestine

The glycoconjugates secreted by the anterior and posterior intestinal segments of Tilapia spp. were characterized by means of both conventional histochemical procedures (PAS, AB, AB-PAS, LID, HID) and a battery of 12 horseradish peroxidase labelled lectins. Some sections were treated with glycolytic enzymes and KOH before conventional and lectin stainings. The large majority of the mucopolysaccharides secreted by the goblet cells of the anterior segment are carboxylated while only a few carry sulphate groups. The mucopolysaccharides in the anterior intestine contained chondroitin, heparin and chondroitinsulphates which can provide protection for intestinal mucosae. DBA lectin staining demonstrated the presence of some endocrine cells in the anterior segment.