Characterization of mucus glycoproteins in the intestinal mucosa of the African elephant (Loxodonta africana) following lectin histochemistry.

The glycoproteins of the small intestines, caecum and colon of three adult elephants and one recently weaned elephant calf were examined by means of lectin histochemistry. Tissue sections were histochemically stained with peroxidase-labelled concanavalin A (Con A), asparagus-pea (TPA), peanut (PNA) and wheat-germ (WGA) lectins. Con A and TPA showed no binding activity in the intestinal tract of the adult elephants or the duodenum and ileum of the elephant calf, but did show a small amount of binding activity in the caecum and colon of the calf. WGA bound very intensely throughout the intestinal tracts of the adults and of the calf--especially with the goblet cells located in the crypts of Lieberkuhn and the glands of Brunner--decreasing in intensity towards the luminal surface of the intestinal tract. PNA stained the glands of Brunner of the duodenum faintly and the goblet cells of the ileum moderately, with no staining of the caecum and faint staining of the colon. These results show the distribution of Con A-, WGA-, PNA- and TPA-binding sites, and the changes that take place in the type of glycoprotein secreted after a change in the diet of the animal.