Histological and Histochemical Characteristics of the Kidneys in Different Avian Species

Abstract

Background: Birds vary according to the food they eat that depending on the environment they are live in, including marine birds, wild birds, carnivores birds and domesticated birds, each of which has a diet that makes the kidneys in different types of species perform different, privet and unique functions than those that are different in the environment. Objective: The present work was carried out to investigate the histological and histochemical characteristics of kidneys in six avian species including domesticated bird (Chicken & Pigeon), wild bird & Amphibious bird (Common coot & Purple swamp), and migrated marine birds (Mallard duck & great Flamingoes). Results: The kidney tissue sections were fixed in 10% neutral buffer formalin, prepared by paraffin technique and stained with H & E, Alcian blue (pH 2.5), Periodic acid-Schiff and the mercury bromophenol blue stain. Histologically, there were no differences found in the structure of the kidney among these species. Histochemically the endothelial cells of glomerular capillary tuft were resting on delicate basement membranes which were positive for PAS stain and negative for Alcian blue (2.5pH). The basement membrane of lining cells of all segments of nephrons and brush border of proximal convoluted tubules were positive for PAS stain and negative for Alcian blue (2.5pH). The luminal surfaces of the distal convoluted tubules and collecting ducts were positive For Alcian blue (2.5pH). With combined Alcian blue-PAS stains the distal convoluted tubules and collecting ducts were strongly positive to Alcian blue (2.5pH). The proximal convoluted tubules were the first site where the albumin in composed of spheres formed. Conclusions: The avian nephrons were similar in various birds species showed variable pH reactions substances to produce small renal spheres in proximal tubules, consequently the harmful effect of the uric acid crystals prevented by a chemical binding of uric acid with matrix protein.