HISTOCHEMICAL ASPECTS OF THE YOLK-SAC AND DIGESTIVE-TRACT OF LARVAE OF THE SENEGAL SOLE, SOLEA-SENEGALENSIS (KAUP, 1858)

Histochemical distribution of glycoproteins, carbohydrates and protein s rich in different aminoacids were studied using histological and his tochemical procedures, in Senegal sole, Solea senegalensis (Kaup, 1858 ) larvae from hatching until day 15. Glycogen, proteins and glycoprote ins were detected in the yolk-sac of the larvae at hatching and during the yolk-resorption. The epithelial digestive system (brush border, e nterocytes and goblet cells) contained neutral and acid mucins (carbox ylated and/or sulphated). Glycogen was observed in the cytoplasm of th e digestive absortive cells (enterocytes) and in the liver (hepatocyte s) on day 3-4 posthatching. Protein reactions, and specially those tha t showed proteins rich in arginine, tyrosine and tryptophan, were very intense in the zymogen granules of the pancreatic cells. Oesophageal and intestinal goblet cells contained glucose N-acetyl and sialic acid residues, but the mucin content of these mucous cells did not show af finity towards Con-A, suggesting the absence of glycoproteins with Man nose and/or glucose residues. WGA showed a very intense positivity in the microvilli of the digestive epithelium of the larvae and positive granules for both lectins, specially for Con-A, were detected in the c ytoplasm of the anterior intestinal enterocytes.