Interrenal-Chromaffin Tissue Ratio in the Adrenal Gland of Kuttanad Ducks (Anas Platyrhynchos Domesticus) During Post Hatch Development

The interrenal- chromaffin tissue ratio (IC ratio) in the adrenal gland of Kuttanad ducks was studied during post hatch development in 78 female birds of 13 age groups from day-old to 24 weeks of age at fortnightly intervals. The measurement was read out from the pictures by the use of “ImageJ software”. The proportion of interrenal tissue in the whole gland was least at sixth week of age (1.15:1). However, the highest percentage of interrenal tissue in all the three zones (subcapsular, inner and central zones) was noticed at 18 weeks of age. Interrenal-chromaffin tissue ratio in the whole gland revealed that the interrenal tissue predominated the chromaffin tissue throughout the post hatch period in Kuttanad ducks. The functional significance of higher proportion of cortex is not fully understood, but one possible explanation could be the increased need to regulate water and electrolyte balance in ducks. The highest IC ratio of 2:1 was attained in 18 weeks-old birds when all the birds started laying eggs. This might be due to the fact that when the bird is exposed to stress (egg laying), the adrenal glands release corticosterone and catecholamines into the blood, which help the bird to adapt to new conditions.