Structure and functional significance of branched anastomosing mucosal folds in the proximal intestine of the farmed African catfish (Clarias gariepinus Burchell 1822)

Histology has provided morphologist a powerful tool that enhances the nature, form and detailed structure of organs. The proximal intestine though a more muscular tube than the rest of the intestine presented a complex anastomosing mucosal fold resembling a honey comb-like structure. This specialization was not seen in the other intestinal segments. This specialization increases the surface area for nutrient absorption. This probably compensates for shortness of intestine and absence of pyloric caeca in this species. The glycoconjugates in the goblet cell of proximal intestine mucosal fold were subjected to mucin histochemical study. The study revealed the presence of neutral andacid mucin but acid mucin was predominant. The neutral mucin can be associated to buffering the effect of gastric acid, transport of small disaccharide molecules. The predominating acid mucin suggest air-breathing function since the acid will always make the epithelium moist for gaseous exchange between dissolved air in swallowed water and abundant blood vessels present in the tunica mucosa.Keywords: Nutrient absorption, Proximal intestine, Anastomosing mucosal folds, Histology, Histochemistry, Clarias gariepinu