Effects Of Salinity Of Drinking Water, State Of Hydration, Dietary Protein Level And Unilateral Nephrectomy On Blood Constituents And Renal Function In Nubian Goats

Abstract

Experiment 1: Water salinity (1.5% NaCl) increased water consumption and decrease food intake significantly, while rectal temperature (Tr) and body weight (BW)were not significantly affected. The packed cell volume (PCV) decreased significantly with saline water. Likewise, the serum urea level decreased, however, serum total protein and albumin concentrations were not significantly affected by salinity. On the other hand, serum creatinine increased significantly in the treated group in weeks 5 and 6. A slight decrease in plasma glucose was observed in the treated animals while serum Na and K levels were not significantly affected; however, Naand K levels decreased during the first 4 weeks, while Na level tended toincrease in the last 2 weeks. Urea level decreased significantly in the first 3 weeks then tended to increase. Urine value and GFR increase significantly. Experiment 2: Involved dehydration and hydration states. The dehydrated goats (3 days) drank 4.6 litre after 15 minutes of rehydration, beside BW loss regain. Rehydration also corrected the significant decrease in food intake within 2 days, associated with normal body temperature which increased with dehydration together with PCV. Dehydration significantly increased serum total proteins, albumin, urea, creatinine and osmolality, and all retuned to the normal level in the second dary of rehydration. However, the significant decrease in urine volume and GFR, which returned tocontrol level after 3 days of rehydration. Dehydration was associated with significant increase of urine urea which decreased to control values in the second day of rehydration. Experiment 3: Increasing dietary protein level resulted in a significant increase in water consumption and a significant decrease in daily food intake, however, there was no significant difference in either parameter between low and medium levels. The mean BW of goats decreased significantly by increasing protein level in diet; the difference was significant between the high and low levels, but it was insignificant between the high and medium and low and medium levels. There was a slight increase in PCV of the medium level compared to the high and the low level. Serum total protein and albumin levels were not significantly affected by changing dietary protein level, while serum urea level increased significantly and progressively with increase in dietary protein level. Serum creatinine level decreased significantly with increasing dietary protein level. Urine volume and GFR increased significantly with increased dietary protein level. Urine K level decreased significantly and urine urea level increased significantly with increase dietary protein level. Experiment 4: the unilateral nephrectomy resulted in significant increase in the weight ofthe contralateral kidney in the Unix animals compared to sham-operated animals. Ultrasonographic measurements indicated significant increase in the volume of the remaining kidney as a result of compensatory renal growth. Also unilateral nephrectomy resulted in a significant increase inthe diameters of nephron components (glomerulus, proximal and distal tubules) and decrease in Bowman space as a result of compensatory renal growth. Unilateral nephrectomy resulted in significant increase in relative medullary thickness ( RMT). No significant difference could be detected between UniX and sham-operated goats related to unilateral nephrectomy in water consumption, BW and Tr throughout the experimental period. Erythrocytic indices: erythrocyte count, PCV and Hb concentration were not significantly affected by unilateral nephrectomy; and it was not associated with significant changes in serum total protein, albumin and osmolality. Serum creatinine level significantly increased in UniX goats particularly in the first three weeks,compared to sham-operated group. Serum urea level, plasma glucose level serum Na, K level and cortisol were not significantly affected by unilateral nephrectomy. Urine volume slightly decreased inUniX goats in the first weeks compared to sham-operated, while the GFR in UniX goats significantly decreased compared to sham-operated. No significant effects were observed in urine Na, K, and urea levels related to unilateral nephrectomy. Drinking saline water significantly increased water consumption at concentration of 0.45, 0.9 % NaCl and slightly decreased food intake. The increase in salt load slightly reduced Tr and BW of UniX and shamoperated animals. The PCV and Hb concentration of normal and UniX goats decreased insignificantly by drinking saline water. The water salinity did not significantly affected serum total protein and albumin level of UniX and sham-operated animals. Serum urea level increased with 0.45% NaCl and then tended to slight decrease with 0.9 and 1.5% NaCl. No significant changes were detected in serum creatinine related to water salinity in UniX and sham-operated animals. Plasma glucose level decreased significantly with increasing water salinity. Serum osmolality was slightly decreased with changing fromtap water to water with 0.45 and 0.9% NaCl and then tended to increase slightly with 1.5% NaCl. The salt load did not significantly affect serum cortisol level of UniX and shamoperated animals. The urine volume increased significantly by increasing concentration of NaCl in drinking water (0.45 and 0.9% NaCl), but it tended to decrease with 1.5% NaCl in UniX and sham-operated animals. GFR was significantly increased by drinkingsaline water in UniX and shamoperated animals. Urine Na level increased significantly with increase salinity of water in UniXand sham-operated animals. The urine K level of UniX and sham-operated animals showed significant decrease with 0.45 and 0.9% NaCl and it tended toincrease with 1.5 % NaCl. Urine urea level of UniX goats was significantly decreased by drinking saline water compared to sham-operated. The effects water deprivation in UniX and sham-operated goats and food intake showed significant decrease in water consumption. By the end of the 3 days of dehydration, the sham-operated animals group reduced their level of food intake by59.44% and UniX group by 50.92%. Dehydration significantly decreased BW ofUniX and sham-operated; by the end of the dehydration period, UniXgoats lost about 13.33% of the initial body weight, while the sham-operated group lost about 14.77%. Sham-operated group regained almost all of their BW losses and UniX exceeded it after 4 hrs following rehydration. Tr of UniX and shamoperated animals showed a decrease related to water deprivation, which attained level of significance in UniX group. The PCV and Hb concentration in UniX and sham-operated animals increased progressively and significantly during water deprivation. Serum total protein level of UniX and sham-operated animals showed a gradual and significant increase during water deprivation period. Serum albumin level in UniX and sham-operated animals exhibited a slow increase in response to water deprivation in the second and third day of dehydration. Serum urea, creatinine level and serum osmolality increased significantly and progressively, while plasma glucose level decreased with increase deprivation period inand sham-operated animals. Serum cortisol level exhibited unsteady pattern due to water deprivation in UniX and sham-operated animals. Urine volume and GFR of UniX and sham- operated goats were progressively and significantly decreased during dehydration. Urine Na and K level of UniX and sham-operated goats indicated no significant differences related to water deprivation. Urine urea concentration of UniX and sham- operated goats showed marked fluctuation during water deprivation. The results obtained in the studies were explained and discussed in the light of previous findingsreported in the literature.