Histological and Ultrastructural studies of Caecal tonsil in Chicken (Gallus domesticus)

The alimentary tract is incessantly invaded by foreign antigenic or harmful substances and their lumina are also sites for the proliferation of both beneficial and disadvantageous bacterial flora (Mead, 1989 and Kitagawa et al., 2000). Caecal tonsil, the immunodefence mechanism of the caecal environment regulates the proliferation of microflora in the caecum continuously and also prevents the invasion of extra caecal microorganisms. This is brought about by organization of enormous lymphoid nodules throughout the caecal mucous membrane forming tonsils (Kitagawa et al., 1998). A little work was done about the light and ultrastructural studies of the caecal tonsils in Chicken. Hence, the present study was designed to explore the details of caecal tonsils in the layer chicken of different age groups.