LAUSR

The present study was aimed to examine histochemical changes in the Harderian gland of pre and post hatched chicks from 11 day of incubation to 24 days of age. In pre hatched groups, the gland was in the developing stage. There was no well defined parenchyma, septa and capsule in early embryonic stage. Histochemical observation revealed that weak or negligible activity of PAS, AB/PAS and Sudan black B was seen in epithelial lining of Harderian gland on 18th and 20th day of incubation. The gland was compound tubule-acinar type at 20th day of incubation, consisted of capsule, parenchyma and stroma. PAS activity was seen in the capsule, septa, epithelial lining of acini and tubule and interstitial connective tissue cells. PAS activity was aggregated towards the apical part of the tubular epithelium as well as at the free luminal surface epithelium of the acini. PAS activity increases with the development of connective tissue component of Harderian gland with the advancement of age. The Harderian gland was predominantly mucus and lipid secreting gland. All epithelial cells of the glandular unit of Harderian gland contain both neutral and acidic mucin. Intense AB-positive activity was seen at the apex of tubule with the advancement of age. Sudan black B activity was recorded in the cytoplasm of epithelial lining of tubule and acini of the Harderian gland and their presence increases with age.