Estimation of phosphorus requirements of sows based on 24-h urinary phosphorus excretion during gestation and lactation

Abstract Phosphorus requirements of reproducing sows were estimated using 24-h urinary P excretion. Thirty-six multiparous sows were fed one of six maize–soybean meal-based diets with total P ranging from 0·40 to 0·80 % in 0·08 % increments with a constant Ca:total P ratio (1·25:1). Diets were fed from day 7·5 ± 1 after breeding until the end of lactation (day 26 ± 1). Urine samples were collected in mid and late gestation (days 77·1 ± 2 and 112·4 ± 1) and early and late lactation (days 4·5 ± 1 and 18·2 ± 1). Phosphorus requirements were estimated using linear and nonlinear regression models. Based on a single 24-h urinary P excretion, estimated daily dietary total P requirements in mid and late gestation were 10·3 g (6·0 g standardised total tract digestible P, STTD P), and estimates for early and late lactation were 31·1 g (16·6 g STTD P) and 40·3 g (22·1 g STTD P), respectively. Plasma P and Ca concentrations were maintained within normal ranges at the estimated levels of P requirements. No differences among treatments were observed for plasma parathyroid hormone (P ≥ 0·06) and bone formation marker (P ≥ 0·16). In lactation, bone resorption marker decreased (P ≤ 0·001) as sows consumed more P. Among the analysed variables, urinary P was the most sensitive response to changes in dietary P intake. Urinary P excretion offers a practical method to estimate P requirements in sows. Our recommended daily total P requirements are 10·3 g for gestation and 35·7 g for lactation.

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65 Evaluation of Calcium to Phosphorus Ratio in Spot Urine Samples as a Practical Method to Monitor Phosphorus Intake Adequacy in Sows

Journal of Animal Science ◽

10.1093/jas/skab054.072 ◽

2021 ◽

Vol 99 (Supplement_1) ◽

pp. 41-41

Author(s):

Mariola Grez Capdeville ◽

Tom D Crenshaw

Keyword(s):

Physiological State ◽

Roc Curves ◽

Strong Relationship ◽

Weighted Kappa ◽

Practical Method ◽

Early Morning ◽

Late Gestation ◽

Urine Samples ◽

Spot Urine ◽

Total P

Abstract The reliability of spot urinary Ca to P ratio (uCa:P) to assess P intake adequacy in sows was evaluated. Thirty-six multiparous sows were fed one of six concentrations of dietary total P (0.40, 0.48, 0.56, 0.64, 0.72, and 0.80%), with a constant Ca to total P ratio (1.25:1), from day 7.5+1 after breeding until the end of lactation (day 26.6+1). Total 24-hour urine samples were collected in mid (day 77.1+2) and late gestation (day 112.4+1), and early (day 4.5+1 and late (day 18.2+1) lactation. In parallel to 24-hour collections, spot urine samples were collected at three times (early morning, late morning, and late afternoon) in late gestation and late lactation. Urine Ca and P concentrations were measured and uCa:P was calculated. Sows were classified as P-adequate or P-deficient according to dietary P intake. Sows fed P-deficient diets had greater uCa:P than sows fed P-adequate diets (P < 0.001). Receiver operator characteristic (ROC) curves were used to determine cut-off values for uCa:P to predict P intake adequacy. The area under the ROC for uCa:P was 0.88 (95% CI 0.81–0.95). Best cut-off value of uCa:P was 1.5 (sensitivity 94% and specificity 68%) to identify sows fed P-deficient diets, and 0.5 for P-excessive diets (sensitivity 82% and specificity 82%). A strong relationship between uCa:P in 24-hour and spot urine samples was determined (r = 0.93, P < 0.01), independent of physiological state and collection time of spot samples (adjusted-R2 = 0.86, P < 0.01). The degree of agreement between spot and 24-hour urine for P intake adequacy, assessed by Cohen’s weighted kappa analysis, was substantial (0.78, 95% CI 0.69–0.88). Measurements of uCa:P in spot urine samples provide a reliable prediction of the adequacy of P intake in reproducing sows. Values of uCa:P > 1.5 were associated with P-deficient diets, whereas uCa:P < 0.5 reflected excessive P intake.

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Effect of RenaGel(R), a non-absorbable, cross-linked, polymeric phosphate binder, on urinary phosphorus excretion in rats

Nephrology Dialysis Transplantation ◽

10.1093/ndt/12.5.961 ◽

1997 ◽

Vol 12 (5) ◽

pp. 961-964 ◽

Cited By ~ 45

Author(s):

D. Rosenbaum ◽

S. Holmes-Farley ◽

W. Mandeville ◽

M. Pitruzzello ◽

D. Goldberg

Keyword(s):

Phosphate Binder ◽

Phosphorus Excretion ◽

Urinary Phosphorus Excretion

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THE EFFECTS OF FEEDING EITHER ROUGHAGE OR CONCENTRATE DIETS ON SALIVARY PHOSPHORUS SECRETION, NET INTESTINAL PHOSPHORUS ABSORPTION AND URINARY PHOSPHORUS EXCRETION IN THE SHEEP

Quarterly Journal of Experimental Physiology ◽

10.1113/expphysiol.1985.sp002922 ◽

1985 ◽

Vol 70 (3) ◽

pp. 365-375 ◽

Cited By ~ 16

Author(s):

D. Scott ◽

W. Buchan

Keyword(s):

Phosphorus Excretion ◽

Phosphorus Absorption ◽

Urinary Phosphorus Excretion

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Combination treatment with tenapanor and sevelamer synergistically reduces urinary phosphorus excretion in rats

AJP Renal Physiology ◽

10.1152/ajprenal.00137.2020 ◽

2020 ◽

Author(s):

Andrew J. King ◽

Jill Kohler ◽

Cyra Fung ◽

Zhengfeng Jiang ◽

Allison Quach ◽

...

Keyword(s):

Male Rats ◽

Phosphate Binders ◽

Phosphate Absorption ◽

Phosphorus Excretion ◽

Sevelamer Carbonate ◽

Sodium Hydrogen Exchanger ◽

Intestinal Phosphate Absorption ◽

Urinary Phosphorus Excretion ◽

Dose Levels ◽

Nhe3 Inhibitor

The majority of patients with chronic kidney disease (CKD) receiving dialysis do not reach target serum phosphorus concentrations, despite treatment with phosphate binders. Tenapanor is a non-binder, sodium/hydrogen exchanger isoform 3 (NHE3) inhibitor that reduces paracellular intestinal phosphate absorption. This pre-clinical study evaluated the effect of tenapanor and varying doses of sevelamer carbonate on urinary phosphorus excretion, a direct reflection of intestinal phosphate absorption. We measured 24-hour urinary phosphorus excretion in male rats assigned to groups dosed orally with vehicle or tenapanor (0.3 mg/kg/day) and provided a diet containing varying amounts of sevelamer (0-3% w/w). We also evaluated the effect of the addition of tenapanor or vehicle on 24-hour urinary phosphorus excretion to rats on a stable dose of sevelamer (1.5% w/w). When administered together, tenapanor and sevelamer decreased urinary phosphorus excretion significantly more than either tenapanor or sevelamer alone across all sevelamer dose levels. The Bliss statistical model of independence indicated that the combination was synergistic. A stable sevelamer dose (1.5% w/w) reduced mean (±standard error of the mean) urinary phosphorus excretion by 42±3% compared with vehicle; together, tenapanor and sevelamer reduced residual urinary phosphorus excretion by an additional 37±6% (P < 0.05). While both tenapanor and sevelamer reduce intestinal phosphate absorption individually, administration of tenapanor and sevelamer together results in more pronounced reductions in intestinal phosphate absorption than if either agent is administered alone. Further evaluation of combination tenapanor plus phosphate binder treatment in patients receiving dialysis with hyperphosphatemia is warranted.

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The importance of the salivary glands in the maintenance of phosphorus homeostasis in the sheep

Australian Journal of Agricultural Research ◽

10.1071/ar9730913 ◽

1973 ◽

Vol 24 (6) ◽

pp. 913 ◽

Cited By ~ 18

Author(s):

RC Clark ◽

OE Budtz-Olsen ◽

RB Cross ◽

P Finnamore ◽

PA Bauert

Keyword(s):

Salivary Glands ◽

Potassium Dihydrogen Phosphate ◽

Phosphorus Loading ◽

Dihydrogen Phosphate ◽

Short Term ◽

Potassium Dihydrogen ◽

Phosphorus Excretion ◽

Phosphorus Absorption ◽

Term Basis ◽

Urinary Phosphorus Excretion

Urinary and faecal phosphorus excretion were measured in five sheep for 4 days after acute intravenous infusion of 3.38 g of phosphorus as potassium dihydrogen phosphate. Urinary phosphorus excretion was increased for 12 hr after the infusion, but urinary phosphorus output was small compared with the marked increase in faecal phosphorus output. The increase in faecal phosphorus excretion coincided with and followed the appearance in the faeces of Cr-EDTA, which had been introduced into the rumen as a marker at the time of the phosphate infusion. This suggests that secretion of phosphorus into gut regions below the reticulo-rumen is not quantitatively altered in response to intravenous phosphorus loading, and that phosphorus absorption is also unaffected (at least not on a short-term basis). The additional phosphorus entered the alimentary canal at the level of the reticulo-rumen, and it was deduced that this occurred predominantly via the salivary glands. Persistence of the increase in faecal phosphorus excretion for some time after the Cr-EDTA marker had been cleared emphasizes the importance of the phosphorus recirculation system to ruminants like the sheep.

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Effect of fasting on tubular phosphorus reabsorption

AJP Renal Physiology ◽

10.1152/ajprenal.1979.237.3.f241 ◽

1979 ◽

Vol 237 (3) ◽

pp. F241-F246 ◽

Cited By ~ 1

Author(s):

N. Beck ◽

S. K. Webster ◽

H. J. Reineck

Keyword(s):

Metabolic Acidosis ◽

Cyclic Amp ◽

Partial Resistance ◽

Tubular Reabsorption ◽

The Other ◽

Partial Reduction ◽

Phosphorus Excretion ◽

Urinary Phosphorus Excretion

In the thyroparathyroidectomized (TPTX) rat, fasting increased urinary phosphorus excretion by decreasing the tubular reabsorption of P1 (TRP) and resulted in hypophosphatemia. The administration of either sucrose or NaHCO3 prevented the metabolic acidosis associated with fasting and decreased the phosphaturia, indicating that the phosphaturia in fasting is in part due to metabolic acidosis. In rats on partial reduction of P1 intake selectively, the phosphaturic response to parathyroid hormone (PTH) was completely suppressed. On the other hand, the fasting rat partially retained the phosphaturic response to PTH, although dietary P1 intake was totally absent. These findings suggest that the renal P1 wasting in fasting may take place by dual mechanisms: a) the PTH-independent decrease in TRP, and b) an inability to totally suppress the response to PTH. Cyclic AMP generation in response to PTH, determined both in vivo and in vitro, was not measurably altered in fasting. However, the phosphaturic response to cyclic AMP was decreased in fasting, suggesting that the mechanism of partial resistance to PTH is probably not at but after cyclic AMP generation.

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