Histological and histochemical studies of Thyroid and parathyroid Glands of Ducks and Geese with special Reference to Laying and Non-Laying variations

The present study was conducted on the thyroid and the parathyroid glands of 84 apparently healthy female ducks and geese at different age periods from one week to maturity and including thelaying and non-laying periods.The specimens were taken immediately after sacrifice and processed till 5-6 micrometer thick paraffin sections were prepared and stained with H & E, Crossmon’s trichrome st., Weigert’s elastic st. Weigerti’s elastic- Van Gieson combination, Mallory’s tripreddish in colour and occurred as one on either side of the trachea, atthe entrance of the chest cavity in close proximity to the commoncarotid arteries and jugular veins, at about the level where the commoncarotid arteries divides to give off the anterior cervical and thevertebral arteries. Microscopically, the thyroid gland was covered with a clear fibrous connective tissue capsule. This capsule was formed mainly of collagenic fibers in addition to some elastic and reticular fibers andcontained blood vessels and nerves. The capsule was thin in young birdsand increased in thickness with the progress of age. There was somelymphocytic aggregation in the capsule of some age groups of geese.The capsule gave trabeculae which were very thin in youngs andincreased in thickness comparatively in advanced ages. The stroma was rich in collagenous and reticular fibers withfewer elastic ones. The vascularity among the follicles was increased inadvanced ages.