Renal clearance of endogenous creatinine and urea in sheep during summer and winter

Simultaneous measurement of the renal clearance of endogenous creatinine and exogenous inulin in eight sheep showed similar mean +/- SD (n = 32) values of 13.8 +/- 1.3 and 13.2 +/- 2.0 ml min-1 (10 kg)-1 bodyweight respectively. These results demonstrate that the renal clearance of endogenous creatinine is a satisfactory measure of glomerular filtration rate (GFR) in sheep. The plasma concentrations of endogenous creatinine and urea were significantly higher because of haemoconcentration during summer, resulting in lower GFR than in winter. Besides glomerular filtration and back diffusion, the renal handling of urea in sheep seems to involve mechanisms analogous to active tubular secretion.     

Effects of high dietary sodium chloride content on performance and sodium and potassium balance in growing pigs

Thirty castrated male Moo Lath pigs (6–8 weeks of age) were used in a 15-week growth trial to study the effect of high dietary sodium chloride (NaCl) content on feed and water intake, performance, sodium (Na) and potassium (K) balance, and plasma aldosterone concentration. The pigs were randomly allocated (ten per treatment) to diets containing 0.24 % Na (Na0.24), 0.28 % Na (Na0.28), and 0.32 % Na (Na0.32) per kg diet. Feed and water was provided ad libitum, and water consumption, feed offered, and feed residues were recorded daily. Every third week, the pigs were weighed, blood samples were collected, and a 3-day total collection of urine and feces was performed. Water intake was higher (P?=?0.001) in pigs fed with diets Na0.28 (3.7 L/day) and Na0.32 (3.9 L/day) than in pigs fed with diet Na0.24 (3.4 L/day), and dry matter (DM) intake was higher on diet Na0.32 (P?=?0.041) than on the other diets. The average daily body weight (BW) gain was higher on diet Na0.32 than on the other diets (P?=?0.031). The feed conversion ratio (in kilogram feed DM to kilogram BW gain) was 4.6, 4.6, and 4.1 on treatments Na0.24, Na0.28, and Na0.32, respectively (P?=?0.14). The highest Na balance was observed on diet Na0.32 followed by diets Na0.28 and Na0.24 (P?<?0.001), while there was no treatment-related pattern for the K balance. The Na/K ratio in feces and urine increased (P?<?0.001), and the K/Na ratio in feces (P?<?0.001) decreased with increasing Na content in the diet. Plasma aldosterone concentration decreased (P?<?0.001) with increasing dietary content of Na. These results indicate that high NaCl intake and free access to water will increase Na balance but do not negatively influence feed intake and performance of growing local pigs.     

Renal sodium and potassium excretion in sheep given amiloride.

When amiloride was given (IV) to unanesthetized ewes, potassium excretion decreased to one-third of baseline values, and sodium excretion increased 6- to 180-fold. Potassium excretion during amiloride administration was relatively invariant with respect to duration (0 to 270 minutes) or rate of amiloride administration (0.125 to 2.0 mg/minute), but sodium excretion clearly increased with both duration and dose rate in individual experiments. This increase was independent of the rate of concomitant saline administration. Thus, sheep fed a normal ration (about 600 mEq of potassium per day) respond to amiloride as do man, dogs, and rats. The relationship of sodium excretion to rate and duration of amiloride administration is not unique to sheep, but has not been stressed in previous studies on other species.     

Dietary sodium and chloride levels for growing-finishing pigs

The performance and the physiological and metabolic consequences of three dietary levels of Na (.03, .09 and .18%) and of Cl (.08, .17 and .32%) arranged factorially were determined in growing-finishing pigs (36 to 89 kg). Average daily gain and feed efficiency of pigs fed .03% Na were lower than pigs fed .09 or .18% Na. Gain:feed ratio of pigs fed .32 or .17% Cl was greater than that of pigs fed .08% Cl during the finishing phase (58 to 89 kg) but not during the growing phase. Increasing dietary Cl levels increased average daily feed intake and gain:feed ratio of pigs fed .03% Na, but had no effect at the higher levels of Na. Plasma Na and Cl were lower (P less than .05) while plasma K (P less than .01), total protein, (P less than .04), albumin (P less than .07) and urea N (P less than .03) were higher in pigs fed .03% Na compared with those fed .09 or .18% Na. Increasing the dietary levels of Cl decreased urea N (P less than .05). Plasma lysine:arginine ratio increased as dietary Cl increased in pigs fed .18% Na diets, but not in pigs fed .03 or .09% Na. The urea cycle intermediate ornithine was highest in the plasma of pigs fed .18% Na. Dietary Na and Cl seem to interact to affect both plasma electrolytes and basic amino acid metabolism.     

Renal excretion of urea and electrolytes in sheep after extracellular fluid expansion with an isotonic solution of sodium chloride

Sheep of the Merino breed, given 10.11 g nitrogen daily (after Czechoslovak Standard CSN 46 7007) were studied for the effect of the expansion of the extracellular fluid (ECF) by an infusion of an isotonic solution of NaCl (at a rate of 5% of live weight), as exerted on the renal excretion of urea and on the sodium and potassium electrolytes. The high natriuresis, induced by the expansion of ECF, resulted in a statistically significant increase in the clearance of urea, free water, and solutions, and in higher diuresis. An increase was observed in the excretion of urea with urine (UureaV; P < 0.005) and in the excretion of the studied electrolytes of sodium (UNaV; P < 0.001) and potassium (UKV; P < 0.005) by the same route. No variation was recorded in the clearance of inulin as a measure of the glomerular filtration rate (GFR). The fractional excretion of urea, sodium, and potassium also showed a significant increase. The results imply that the fractional excretion of urea increases under the conditions of artificially induced natriuresis.     

Circadian changes in blood ionized calcium, sodium, potassium, and chloride concentrations and pH in cattle.

OBJECTIVE: To explore diurnal variation in blood ionized calcium, sodium, potassium, and chloride concentrations and pH in pregnant dairy cows. ANIMALS: 14 dairy cows in their third or later pregnancy approximately 6 weeks before expected parturition. PROCEDURE: Throughout a 24-hour period, blood samples were taken at 2-hour intervals and analyzed for ionized calcium (iCa2+), potassium (K+), sodium (Na+), and chloride (Cl-) concentrations and pH. Paired t-tests were used to compare initial and final values. Circadian changes were tested by use of repeated-measures ANOVA. Additionally, a nonparametric analysis was performed for each animal to determine minimal and maximal values for the variables. RESULTS: Significant differences were not detected between initial and final values of any variable. Repeated-measures ANOVA indicated significant diurnal fluctuations in all variables. With the exception of Cl- concentration, nonparametric analysis of individual values also revealed significant changes over time. CONCLUSIONS AND CLINICAL RELEVANCE: The magnitude of daily fluctuations does not make it necessary to standardize time of sample collection for routine diagnostic examination of blood iCa2+, Na+, and Cl-concentrations and pH. However, it may be important to standardize time of sample collection in comparative studies in which more discrete differences may be identified.     

Interrelationships between dietary concentrations of sodium,potassium and chloride in laying hens

1. Twelve diets, representing the factorial combination of two concentrations of Cl‐ (0.8 and 1.4 g/kg), three concentrations of Na+ (0.5, 1.1 and 1.7 g/kg) and two concentrations of K+ (7 and 12 g/kg) were fed to groups of laying hens for 24 weeks and records taken of their productivity.

2. Different concentrations of Na+, K+ and Cl‐ showed highly significant interactions which were always similar. Thus, a deficiency of Na+ (0.5 g Na/kg) was aggravated by the restriction of Cl‐ (0.8 g/kg), but was partly compensated for by supplementing the diet with K+ (12 instead of 7 g/kg). Without a sodium deficiency other interactions occurred; for example, the higher concentration of K+ became unfavourable if the other two ions were also supplied at the higher concentrations.

3. These results show that, for the laying hen, the optimum concentrations of Na+, K+ and Cl‐ cannot be determined independently but depend upon the concentration of the two others in the diet.     

Effect of sodium nitrite and sodium chloride on growth of lactic acid bacteria.

The effect of NaNO2 and NaCl on the growth of 24 lactic acid bacteria strains isolated from vacuum-packed cooked ring sausages were examined by analyzing different growth parameters with Bioscreen. NaNO2 had a very limited effect on the growth of lactic acid bacteria at 50 and 100 mg/l but at 400 mg/l a more pronounced inhibitory effect was found. Bacterial growth was enhanced by 1-2% (w/v) of added NaCl, while NaCl concentrations above 3% (w/v) had a clear inhibitory effect. Leuconostoc isolates seemed to be more sensitive to sodium nitrite and sodium chloride than homofermentative lactobacilli strains. Among homofermentative lactobacilli, the strains resembling Lactobacillus curvatus were more sensitive to NaCl than those resembling Lactobacillus sake.     

Quantitative measurement of endogenous amino acid absorption in unanaesthetized pigs

The present experiment was carried out with 11 pigs (mean body weight: 53.9 +/- 1.3 kg) fitted with permanent catheters in the portal vein and carotid artery and with an electromagnetic flow probe around the portal vein. They were each subjected to 2 or 3 trials at 3 to 4-day intervals. During each trial the animals received after a previous fasting of 20 h a given amount of a protein-free diet (200 to 1200 g). The blood was collected either continuously for a quantitative determination of amino nitrogen, reducing sugars, urea and ammonia (number of meals 12, mean intake: 727 +/- 60 g) or discontinuously every 30 min between 0 and 8 h after the meal for amino acid analysis (number of meals 8; mean intake 709 +/- 105 g). A rather constant appearance (2 g/h) of amino acids in the portal blood was observed throughout the postprandial period. The intestinal absorption of each amino acid was however variable and represented between 10 and 50% of the daily requirements of the animal during the measuring period (8 h). Glutamine and to a less extent glutamic acid were exceptions as they were taken up by the gut wall from the arterial blood. There was also a marked synthesis of ornithine and citrulline by the latter. Because of the low blood level of urea, there were no apparent exchanges of urea between the blood and the intestine; in contrast, the ammonia absorption represented about 70% of that observed after ingestion of normal protein diets. Most amino acids are largely taken up by the liver and peripheral tissues, but in the case of alanine the syntheses exceed the uptake.     

Resistance of Aujeszky disease viruses, present in the blood of pigs, to potassium thiosulphate and hydrogen chloride

A trial was conducted to study the sensitivity of the Aujeszky disease virus, present in the blood of pigs, to the effect of two preservatives: potassium thiosulphate ( K2S2O5 ) and hydrogen chloride (HCl). The sensitivity of the virus was determined on rabbits infected with pig blood containing Aujeszky disease virus with different additions of the two preservatives. As found, 0.5% of K2S2O5 and 3% of HCl are concentrations fully sufficient for the inactivation of all the viruses present in the blood. Blood preserved in this way can be used for feeding purposes in pig stocks without the hazard of introducing Aujeszky disease in healthy stocks via the blood included in feed rations.     

钠盐对乳房水肿奶牛钠钾氯血清水平的影响

本试验在以往对石河子地区奶牛乳房水肿的调查情况的基础上,对围产期奶牛停止摄入钠盐,统计奶牛乳房水肿发病率、以及检测围产期健康奶牛和乳房水肿奶牛的血清中钠(Na+)、钾(K+)、氯(Cl-)水平。试验结果显示,围产期奶牛限制摄入钠盐前后乳房水肿的发生率分别为29.77%、22.08%,同时检测奶牛血清显示,患乳房水肿奶牛血清钠(Na+)水平为150.03 mmol/L,且极显著高于健康奶牛(P<0.01);乳房水肿奶牛血清钾(K+)水平为5.12 mmol/L,与健康奶牛没有差异;患乳房水肿奶牛血清氯(Cl-)水平为112.13 mmol/L,且显著高于健康奶牛(P<0.05)。试验表明,尽管不添加钠盐会使围产期奶牛乳房水肿发病率有所降低;但围产期奶牛发生乳房水肿的重要原因是特殊生理时期机体钠、氯离子代谢障碍。本次试验不但验证了钠、氯离子代谢障碍引起围产期奶牛发生乳房水肿,而且在临床实践中为本地规模化牛场养殖建议围产期奶牛不补给钠盐提供数据支持。     

Increased dietary sodium chloride concentrations reduce endogenous amino acid flow and influence the physiological response to the ingestion of phytic acid by broiler chickens

1. A total of 240 Ross 308 broilers were used to investigate the effect of sodium (1·5 or 2·5?g/kg), phytate-P (0 or 3·2?g/kg), and phytase (0 or 1000 FTU/kg; 2x2x2 factorial) on endogenous amino acid flow using the enzyme-hydrolysed casein method.

2. The ingestion of phytate increased endogenous amino acid flow (～30%) compared with the phytate-free control diets. Phytase reduced endogenous amino acid flow only when fed in concert with phytate, resulting in a significant phytate x phytase interaction.

3. Increasing dietary sodium concentration from 1·5 to 2·5?g/kg reduced endogenous amino acid flow by around 10%. This reduction of endogenous flow was particularly evident in diets which contained phytate, resulting in a significant sodium x phytate interaction for several amino acids, including Thr and Ser. Further, high sodium concentrations muted the effect of phytase resulting in a significant sodium x phytase interaction for some amino acids.

4. The concentration of Asp, Thr, Ser and some other amino acids was increased in the endogenous protein in response to the ingestion of phytate. Both sodium and phytase essentially restored the composition of endogenous protein to that of the phytate-free control. Further, as both sodium and phytase had similar effects there were significant interactions between sodium and phytase for most amino acids, such that one was only effective in the absence of the other.

5. These data confirm previous reports that phytate is a nutritional aggressor, causing quantitative and qualitative changes in endogenous protein flow. However, this is the first report which has shown that dietary sodium concentrations play a role in the severity of this antinutritional effect and consequently may blunt the efficacy of exogenous phytase. The mechanism is obscure, though it has been previously demonstrated that sodium can disrupt phytate:protein complexes, thus mitigating one of the mechanisms by which phytate exerts its antinutritional effect.     

Renal excretion of creatinine, electrolytes, protein, and enzymes in healthy sheep

Urinary indices of renal function and damage were measured in 6 healthy, mature ewes over a 48-hour period. Endogenous creatinine clearance, total and fractional electrolyte excretion rates, protein excretion, urine volume, and urine gamma-glutamyltransferase and beta-glucuronidase activities were measured. Significant variations in the excretion rates of creatinine, electrolytes, and protein were not found between intervals within the 48-hour urine collection period. Total urinary electrolyte excretion rates were significantly (P less than 0.001) correlated with fractional electrolyte excretion rates normalized for creatinine concentration; however, coefficient of determination was low.     

Renal excretion of urea in reindeer. Effect of nutrition.

Renal reabsorption of urea was studied in 8 9-month old reindeer calves fed low protein (19–34 g crude protein, mostly lichens) and high protein (68–69 g crude protein, lichens + soybean meal) diets.Low protein diets fed for a 3-month period resulted in an average renal reabsorption of 93% of the filtered urea, while only 50 % was reabsorbed on the high protein ration. It was calculated that if the reabsorbed urea was used completely for protein synthesis in the rumen, 4 g crude protein could be made daily in the lichen fed animals. This amount would be a very significant contribution to the nitrogen economy of animals which are usually in a negative nitrogen balance when lichens are the main food consumed.