EFFECT OF HABITAT DIFFERENCE, SALT-LOADING AND DEHYDRATION ON THE KIDNEY ULTRA STRUCTURE AND FUNCTION OF TWO SPECIES OF FOXES INHABITING TOW DIFFERENT HABITATS.

Eeffect of different habitat, salt-loading and dehydration on the kidney ultrastructure and function of Red Fox Vulpes vulpes and Fennec Fox Vulpes zerda are investigated. Red Fox are found in wet habitat, however, Fennec Fox in sand dune habitat of arid areas in desert. Transmission electron micrograph of glomerulus, proximal and distal convoluted tubules are investigated, Blood urea, serum creatinine, and uric acid of the two fox species are done. These investigations are carried out on normal, salt-loaded and dehydrated individuals of the two species.
Glomerulus revealed normal structure with red blood corpuscles within glomerular capillary, endothelial cells, podocytes and podocyte pedicels. In salt-loading and dehydrating Vulpes vulpes and Vulpes zerda normal glomerular structure are found except degraded podocyte pedicels.
Proximal convoluted tubule (PCT) in normal Vulpes vulpes with brush border, plasmalemma, mitochondria and lysosomes are normally found. In salt-loaded animals large number of vacuoles, mitochondria and lysosomes, but in dehydrating ones brush border fragmentation takes place as well as large number of vacuoles, mitochondria and lysosomes. In normal Vulpes zerda small number of vacuolation, mitochondria and lysosomes are found. In salt-loading and dehydrating animals large number of vacuoles, mitochondria and lysosomes are found.
Distal convoluted tubule (DCT) in normal Vulpes vulpes has large lumen. In salt-loaded animals DCT was found having very narrow lumen and in dehydrating ones DCT with narrow lumen , large number of mitochondria and lysosomes are present.In normal Vulpes zerda the DCTwith large lumen, mitochondria and lysosomes. In salt-loaded animals wide lumen, large number of vacuoles, mitochondria and lysosomes are present and in dehydrating ones DCT with very narrow lumen and large intercellular space is present.
The biochemical analysis revealed significant increase (p < 0.05) in serum uric acid of investigated fox species by the effect of salt loading. Serum urea concentration decreased significantly (p < 0.05) in salt-loading Vulpesvulpes put significantly increased (p < 0.05) in Vulpes zerda, however, the serum creatinine of Vulpes zerda was found decreased, it is increased but insignificantly in the blood serum of Vulpes vulpes. Also, in the dehydrating animals both uric acid and creatinine are significantly increased (p < 0.05) in the serum, whereas, the concentration of serum urea decreased in Vulpes vulpes and increased in Vulpes zerda.
Results show marked variations in kidney ultra structure and function of the studied species as the result of different habitat type and in response to dehydration and salt loading
Kidney function; ultrastructure; foxes; habitat; dehydration; salt loading