Large intestine in pheasant (phasianus colchicus) and see-see partridge (ammoperdix griseogularis). A comparative morphological and histological study

Anatomical and histological studies of the large intestine in birds are essential for necropsy and histopathological examinations. On the other hand, large intestine plays a critical role in the immune system and absorption. The present study's objective was to provide information about the morphological, morphometric and histological characteristics of the large intestine in see-see partridges (Ammoperdix griseogularis) and pheasants (Phasianus colchicus). These two members of the Galliformes order are found in large areas of Iran. In this study, ten male see-see partridges and ten male pheasants were randomly selected. Also, the histological studies were carried out on tissue specimens using haematoxylin for staining. In both species, the cecum was visible as two large tubes at the beginning of the rectum. The cecum and rectum's outer surfaces were flat and had no sacculation in both of the birds. Histologically, intestinal villi in all the large intestine parts and increase their height from the base to the apex is remarkable. The muscularis mucosae was distinct, and lymph nodes and Liberkuhn glands were found in all parts of the large intestine, approximately. It can be concluded that the morphology of the large intestine is very similar to the other avian species, but there are more differences in the histological features. These structural features are in full accordance with the bird's habits and diet.