COMPARATIVE HISTOMORPHOLOGICAL STUDY ON THE THYMUS WITH REFERENCE TO ITS IMMUNOLOGICAL IMPORTANCE IN QUAIL, CHICKEN AND DUCK

A comparative histomorphological study was conducted on thymus of broiler chicken, duck and quail. The thymus of all three species of post-hatch (adult) birds showed a thin connective tissue capsule. However, fine septa originating from the capsule divided the organ into incomplete but distinct lobules in chicken, whereas lobules were ill defined in both quail and duck. Each lobule, in turn, was composed of a peripheral cortex, densely studded with lymphocytes and a central medulla that was enriched with epithelial reticular cells. So, the cortex appeared more basophilic than that of medulla. But the concentration of lymphocyte, an immune competent cell was highest in chicken followed by duck and quail. Hassall’s corpuscles like structures were found inside the medulla as pale stained diffuse body. General histo-architecture was almost similar in all the birds.