GROSS AND HISTOLOGICAL STUDIES ON THE DEVELOPMENT OFTHYMUS IN POSTNATAL AGE GROUPS OF SHEEP (OVIS ARIES)

In the present study, the development of thymus in postnatal sheep was studied. At 2 months of age, the thymus appeared pale pink and changed to greyish yellow with age. The thymus of the sheep showed fat deposits at 4 months of age. Histologically, the sheep thymus showed an increase in connective tissue fibers viz., collagen, reticular and elastic fibers in the capsule, interlobular septa, and trabeculae. The Hassall's corpuscles appeared round, elongated, and irregularly shaped. At 2 years of age, involution of the thymus was noticed with more deposition of fat. The depletion of lymphocytes was noticed in the cortex and medulla at 3 years of age.