Post Hatch Development of Chromaffin Tissuein the Adrenal Gland of Kuttanad Ducks (Anas Platyrhynchos Domesticus)

The study was conducted to understand developmental pattern of chromaffin tissue in the adrenal gland of Kuttanad ducks (Anas platyrhynchos domesticus) during post hatch period. In day-old birds, chromaffin islets were irregular in shape and consisted of lightly and darkly stained cells. Among the two types of chromaffin cells, the darker norepinephrine cells predominated over the light epinephrine cells in day-old birds. By six weeks, chromaffin tissue became highly active with granular cytoplasm. Large number of small and large ganglion cells appeared at this stage and were found associated with the chromaffin tissue. At 10 weeks, most of the chromaffin tissue was seen concentrating towards the central zone of the gland.  At 12 weeks, the chromaffin cells showed numerous granules and most of the islets were surrounded by venous sinuses.  Nuclear diameter of chromaffin cells was greater than those of the interrenal cells in all the age groups.  Many cells in the chromaffin tissue showed two to three nucleoli in the nucleus. At 18 weeks, chromaffin cells were seen trapped in the capsule as solitary cells and as islets.  Another feature was that the chromaffin tissue started aggregating near the sinusoids. Large number of chromaffin islets was distributed in the centre of the gland and crowded around the venous sinuses. In the adult birds (24 weeks), the most important peculiarity noted was the arrangement of chromaffin tissue. They formed columns of cells in between the inter-renal cords and each column extended from the capsule and reached upto the central zone.