An investigation of the nature of the inner lining of the gizzard of a fish-eating bird Pelecanus phillippensis.

An investigation was conducted on the histology and chemical nature of the inner lining of the gizzard of a fish-eating bird Pelecanus phillippensis. 2. The gizzard lining in this bird is extremely thick measuring more than 1.5 mm thick and comprised of 4 zones distinguishable based on physical and chemical properties. 3. Histochemical studies disclose that the outer-most zone is the hardest of all and the stabilization is due to both quinone and organic sulphur. The second zone is hardened by aromatic tanning while the third one has -S-S- bonds. The inner most fourth zone is unhardened and contains a collagenous protein. 4. Electrophoretic and chromatographic studies reveal the presence of 4 proteins with different amino acid composition. 5. The mucin extracted from the gizzard lining has three sugars which are identified as glucosamine, glucose and fucose. 6. The results obtained in the present study have been discussed in relation to the pertinent previous literature.