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Frontiers in Animal Science
Frontiers in Animal Science
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Abstract: |
Compared to other mammals, Arabian camels are ideal models for exploring the
structural adaptations that enable camels to survive in arid environments. Thus, this
study aimed to explore how evolutionary adaptation to arid conditions modifies
the characteristics of the kidneys in Arabian camels (Camelus dromedarius)
compared to oxen. Urine samples were physically and chemically analyzed.
Harvested kidneys were subjected to topographical and fast spin echo magnetic
resonance (FSE-MR) imaging. Histology, histomorphometry, and Aquaporin-2
(AQP2) expression by immunohistochemistry were also performed. Here, in
dromedaries, sodium and potassium values in the urine were much higher
(p=0.001, for both), whereas chloride was much lower (p=0.004) than the
values of oxen. Compared with oxen, the level of the hormone aldosterone in
serum was significantly lower (p=0.002), whereas creatinine and urea were
significantly higher (p=0.005 and p=0.001, respectively). Uric acid in
dromedaries and oxen did not differ significantly (p=0.349). Like sodium levels
(p=0.001) in dromedary serum, chloride was also much higher (p=0.002) than in
oxen. The average value of potassium was much lower (p=0.009) than that of
oxen. Morphologically, anatomical and FSE MRI studies revealed that minor and
major calyces were not found in dromedary kidneys. The renal pelvis was not
found in oxen, and the major calyx was directly connected to the ureter. The
dromedary kidney contained a wider medullary portion as well as increased
collecting tubules (CTs, p<0.05) compared with the oxen. We also noted that
AQP2 was significantly expressed in dromedary nephron components, except for
RCs, compared with oxen as shown by immunohistochemistry. Overall, these data
strongly suggest that the dromedary has a greater ability to adapt to harsh desert
conditions in terms of producing highly concentrated urine than oxen diameters for renal corpuscles (RCs), proximal convoluted tubules (PCTs), and
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