Histology and carbohydrate histochemistry of the alimentary canal in the rainbow trout Oncorhinchus mykiss

A histological and histochemical analyses were carried out on the entire alimentary canal of the rainbow trout Oncorhynchus mykiss. In particular the oesophageal region showed presence of terminal β-D-galactose(1-3)-N- acetylgalactosamine and α-N-acetylgalactosamine. In the anterior and posterior regions of the stomach, lining epithelium and gastric pits exhibited the presence of β-gal and α-GalNAc. In addition sialoglycoconjugates having sialic acid-β-galactose(1-3)-N-acetylgalactosamine and sialic acid-N-acetylgalactosamine as terminal tri- and di-saccharides, were demonstrated. In proximal and distal intestine goblet cells showed the presence of sialoglyconjugates, having sialic acid-β-gal(1-3)-GalNAc and sialic acid-GalNAc as terminal sequences, belonging to N-linked chains. In the enterocytes of the entire intestine, terminal GlcNAc, α-Gal, α-fucose were found.