Pre-hatched Developmental Changes of Harderian Gland in Chicken

The present study aimed to explore histogenesis of the Harderian gland of chicken from the 11^th to 20^th day of incubation. The Harderian gland was situated in the orbit, postero-medial to the eyeball in the embryo and loosely attached by periorbital fascia to the underlying muscles. The primordial Harderian gland appeared as an aggregation of undifferentiated cells on either side between interorbital septum and the retina, on 11^th day of incubation. By the 16^th day of incubation, gland was seen as elongated tube with little contortion of the lumen bounded by epithelial cells which subsequently became large on the 18^th day of incubation. The gland appeared as branched tubular structure and gave rise to out pocketing in the mesenchyme. At the 20^th day of incubation, the Harderian gland was seen to be a branched tubuloacinar type surrounded by thin layer of connective tissue. The acini formation was well defined and intralobular ducts with large lumen were seen in the parenchyma.