COMPARATIVE MICROANATOMICAL FEATURES OF THE RENAL CORTEX IN EMU (Dromaius novaehollandiae) AND DUCK (Anas platyrhynchos)

The present study was conducted on each of the three adult birds of Emu and Duck procured from the farms located in and around Gannavaram. The renal parenchyma of Emu and Duck was divided into large cortical lobules and smaller medullary lobules/cones. The renal cortex of both the birds showed a labyrinth of tubules and renal corpuscles. Small loopless cortical (reptilian type) nephrons and larger looped juxtamedullary (mammalian type) nephrons were observed. The cortical renal corpuscles were found to be numerous than the juxtamedullary nephrons in both the birds. The number of reptilian type of nephrons in Emu were relatively more in a given field area than that of Duck. Both types of renal corpuscles showed all parts of juxtaglomerular apparatus. The capsular space in the renal corpuscle of cortical and medullary nephrons of Emu were greater than that of Duck. Proximal convoluted tubules were lined by high cuboidal cells with spherical nuclei located at the basal level in Emu and Duck. Distal convoluted tubules and collecting tubules in both the birds were lined by low cuboidal cells. Except at the vascular pole the lumen of the distal convoluted tubules in Duck were wider than those of Emu. Numerous peritubular sinuses lined by simple squamous epithelium were observed which drained into the interlobular veins. Lymphoid aggregations were observed between the renal tubules of both the birds.