author(s)
Anil Deka, NN Barman, Sukanta Das, Bhaskar Choudhury, and P Kakati

abstract
The present study was conducted on duodenum of Cattle, Elephant and Greater one Horn Rhinoceros for histology and scanning electron microscopy. The mucosal surface of duodenum of cattle, Elephant and Greater one Horn Rhinoceros contained villi and villi were lined by simple columnar epithelium. Lamina propria-submucosa contains intestinal gland along with abundant collagen fibers. Tunica muscularis layer was composed of thick inner circular and outer longitudinal layer. In Elephant, Tunica muscularis as well as Tunica serosa layers were more prominent compared to the Cattle and Rhinoceros. Abundant connective tissue fibers were found in the tunica sub mucosa layer. In scanning electron microscope, the duodenal villi of cattle were broad and wide with a short height along with numerous opening of goblet cells. In Elephant, the shapes of the duodenal villi were leaf shaped and taller than Cattle. The thicknesses of the muscle fibers were more compared to the Cattle and Rhinoceros. In Rhinoceros, the height of the villi was more compared to the Cattle and Elephant. The villi were cone shaped with a broad base and a pointed apex. These villi contain numerous enterocytes along with opening of goblet cells.