Dietary phosphorus requirement of silver CARP (Hypophthalmichthys molitrix) fingerlings.

The aim of this study was to determine the optimal dietary phosphorus (P) requirement and its effects on growth performance, body composition, mineralization and alkaline phosphate (ALP) activity in silver carp (Hypophthalmichthys molitrix). A total of 360 fish with an average initial weight of 7.0 ± 0.15 g were divided into 18 tanks (70 L capacity each) with a stocking density of 20 fish per tank in triplicate. The fish were fed diets containing six levels of P (3.3, 4.4, 5.5, 6.5, 7.5 and 8.6 g/kg) up to satiation for 90 days twice daily at 09:00 and 16:00. The results showed that fish fed diets containing 6.5 and 7.5 g/kg dietary P had significantly higher (p < 0.05) growth performance in terms of final weight gain, average weight gain (AWG), weight gain% (WG%), protein efficiency ratio (PER) and specific growth rate (SGR) than fish fed other diets. The best value of the feed conversion ratio (FCR) was observed in fish fed the 6.5 g/kg P diet, which was not significantly different from the 7.5 g/kg P diet. Increasing P supplementation above 6.5 g/kg significantly reduced (p < 0.05) the feed intake of silver carp. Whole-body composition analysis indicated that increasing P levels resulted in a decrease (p < 0.05) in crude fat (CF) and an increase (p < 0.05) in crude ash (CA) content, while crude protein (CP) and moisture content remained unaffected (p > 0.05). Fish fed diets containing ≥6.5 g/kg P had significantly higher (p < 0.05) Ca content in the whole body, bones and scales compared to those fed diets containing ≤5.5 g/kg P. A similar trend was observed for P and Mg contents in the whole body, bones and scales. The Zn content tended to decrease (p < 0.05) with increasing P supplementation in the whole body and bones, but fish fed diets containing ≥6.5 g/kg P had significantly higher (p < 0.05) Zn content compared to fish fed diets containing ≤5.5 g/kg P. The Ca/P ratio was significantly affected by P supplementation. Fish fed diets containing ≥6.5 g/kg P had significantly higher (p < 0.05) Ca and P contents in the serum than fish fed other diets. ALP activity increased (p < 0.05) with increasing P levels up to 6.5 g/kg P and decreased (p < 0.05) thereafter. In conclusion, supplementing P up to 6.35 g/kg is recommended for the optimal growth of silver carp.

A U-shaped association between dietary phosphorus intake and new-onset diabetes: A nationwide cohort study in China.

BACKGROUND AND AIMS: The association between dietary phosphorus intake and the risk of diabetes remains uncertain. We aimed to investigate the relation of dietary phosphorus intake with new-onset diabetes among Chinese adults. METHODS AND RESULTS: A total of 16,272 participants who were free of diabetes at baseline from the China Health and Nutrition Survey were included. Dietary intake was measured by 3 consecutive 24-h dietary recalls combined with a household food inventory. Participants with self-reported physician-diagnosed diabetes, or fasting glucose ≥7.0 mmol/L or glycated hemoglobin ≥6.5% during the follow-up were defined as having new-onset diabetes. During a median follow-up of 9.0years, 1101 participants developed new-onset diabetes. Overall, the association between dietary phosphorus intake with new-onset diabetes followed a U-shape (P for nonlinearity<0.001). The risk of new-onset diabetes significantly decreased with the increment of dietary phosphorus intake (per SD increment: HR, 0.64; 95%CI, 0.48-0.84) in participants with phosphorus intake <921.6 mg/day, and increased with the increment of dietary phosphorus intake (per SD increment: HR, 1.33; 95%CI, 1.16-1.53) in participants with phosphorus intake ≥921.6 mg/day. Consistently, when dietary phosphorus intake was assessed as quintiles, compared with those in the 3rd quintile (905.0-<975.4 mg/day), significantly higher risks of new-onset diabetes were found in participants in the 1st-2nd quintiles (<905.0 mg/day: HR, 1.59; 95%CI, 1.30-1.94), and 4th-5th quintiles (≥975.4 mg/day: HR, 1.46; 95%CI, 1.19-1.78). CONCLUSIONS: There was a U-shaped association between dietary phosphorus intake and new-onset diabetes in general Chinese adults, with an inflection point at 921.6 mg/day and a minimal risk at 905.0-975.4 mg/day of dietary phosphorus intake.

Academy of Nutrition and Dietetics Commentary on the Phosphorus Recommendation in the KDOQI Clinical Practice Guidelines for Nutrition in CKD: 2020 Update.

The Kidney Disease Outcomes Quality Initiative Clinical Practice Guidelines for Nutrition in Chronic Kidney Disease: 2020 Update recommends adjusting dietary phosphorus to maintain a serum phosphate goal for hemodialysis patients in the normal range (0.81 to 1.45 mmol/L [2.5 to 4.5 mg/dL]). This is lower than the serum phosphate goal used by many dialysis centers (0.97 to 1.78 mmol/L [3.0 and 5.5 mg/dL]). Although context and clinical judgment must always be considered when providing individualized care to patients, a guideline implementation study conducted from December 2020 to December 2022 found that, based on their documentation, registered dietitian nutritionists from two national dialysis chains are almost universally using dialysis center goals instead of the lower phosphate goal recommended by the guideline. This commentary discusses the possible barriers to implementing the Kidney Disease Outcomes Quality Initiative 2020 nutrition guideline's phosphorus recommendation and proposes a systems level approach to promote and support adoption of the recommendation. Calls to action for potential changes in clinician practices, organizational/institutional culture, and government regulations are put forth.

Dietary phosphorus supplementation in the diet of Pacific white shrimp (Litopenaeus vannamei) alleviated the adverse impacts caused by high Clostridium autoethanogenum protein.

The study evaluated the effects of dietary phosphorus supplementation on the fishmeal replacement with Clostridium autoethanogenum protein (CAP) in the diet of L. vannamei. Four isonitrogenous and isolipid diets were formulated: the PC diet contains 25% fishmeal, the NC, P1 and P2 diets were replaced 40% fishmeal with CAP and supplemented with 0, 0.8 and 1.6% NaH2PO4 respectively (equivalent to dietary phosphorus level of 0.96%, 1.12% and 1.27%). Sampling and V. parahaemolyticus challenge test were conducted after 50-day-feeding (initial shrimp weight 1.79 ± 0.02 g). The results showed that there were no significant differences in the growth performance of shrimp among the 4 groups. The expressions of dorsal in the gut were significantly lower in shrimp fed the P1 and P2 diets than shrimp fed the NC diet and the expression of peroxinectin in the gut was lower in shrimp fed the NC diet than others. The cumulative mortality of shrimp after V. parahaemolyticus challenge was significantly lower in shrimp fed the P2 diet than those fed the NC diet. After the challenge, genes expressions related to the prophenoloxidase activating system (proPO, lgbp, ppaf) were inhibited in the hepatopancreas of shrimp fed NC diet but activated in shrimp fed the P1 diet compared to those fed the PC diet. The AKP and T-AOC activities were higher in shrimp fed the P2 diet than those fed the other diets. The thickness of muscle layer of shrimp fed the P1 diet was thicker than that in the other groups, and significant stress damage happened in the midgut of the shrimp fed the NC diet. The abundance of Pseudoalteromonas, Haloferula and Ruegeria in shrimp fed the P1 diet was higher than those fed the other diets, while Vibrio in shrimp fed the P2 diet was higher than those fed the other diets. This indicated that a low fishmeal diet with dietary phosphorus level of 1.12% could improve the histology, enhance immune response, and increase the abundance of beneficial bacteria in the gut of shrimp. The low fishmeal diet with dietary phosphorus level of 1.27% could improve disease resistance and antioxidant capacity, but there was a possibility of damage to the gut histology as well as increasing abundance of Vibrio in the gut microbiota of shrimp.

Low dietary phosphorus impairs keel bone health and quality in laying hens.

1. Phosphorus (P) is a necessary nutrient for egg production and bone quality in poultry diets. To investigate the effects of low dietary available P (avP) on keel bone, 180 laying hens were fed either a control (C, 0.3% avP) or low phosphorus (LP, 0.15% avP) diet from 20-36 weeks of age (WOA). Each diet was replicated in six cages with 15 birds per cage. Keel samples were collected at 24, 28, 32, and 36 WOA to measure indicators.2. The incidence of keel bone damage in the LP group was higher than C group and increased with age throughout the experiment period. Keel bone length from laying hens in the LP group was shorter than C group (P < 0.05) at 32 and 36 WOA.3. The mRNA expression of receptor activator of nuclear factor kappa-B ligand (RANKL) and ratio of RANKL to osteoprotegerin (OPG) were upregulated (P < 0.05), and that of sclerostin and OPG was downregulated (P < 0.05) in the LP group in comparison to hens in the C group. Meanwhile, mRNA expression of the integrin-binding sialoprotein was increased at 24 and 28 WOA (P < 0.05), and decreased at 32 and 38 WOA (P < 0.05) in the LP group.4. Laying hens in LP group had increased trabecular separation and bone surface fraction (P < 0.05), decreased bone volume, bone volume fraction, trabecular number and thickness, and bone mineral density (P < 0.05) at 32 WOA. The LP-fed hens had increased K, Ti, Mn, Fe, Zn, Se, Sr and Pb bone concentrations (P < 0.05), and decreased P and TI bone concentrations (P < 0.05) at 36 WOA.5. Feeding hens a P-deficient diet with 0.15% avP and 3.37% Ca during the laying period impaired keel bone quality, which could be related to the osteoporosis.

Daily energy expenditure in rats following structured exercise training is affected by dietary phosphorus content.

P ingestion has been found to alter energy balance, while regular physical exercise (E) was reported to be associated with energy compensation. However, it is not clear whether dietary P would affect energy compensation following structured E. Two experiments were performed, low P (LP) (0·1, 0·2 and 0·3 %P) and high P (HP) (0·3 , 0·6 and 1·2 %P) diets. In each experiment, male rats were randomly divided into three groups (n 8), in which a sedentary or a moderate-intensity exercise routine (30 min 5 d a week) was implemented. Energy intake (EI); efficiency and stores; body measures and total energy expenditure (TEEx) were monitored for 6 weeks. In the LP experiment, EI and weight gain were the lowest in the 0·1 and 0·2 %P as compared with the 0·3 %P. In the HP experiment, EI was highest in the high P (0·6 and 1·2 %P) groups, while weight gain was reduced. In both experiments, exercise was able to reduce body fat accumulation and to maintain a higher % lean body mass. In the LP diets experiment, the similarity in TEEx between the sedentary and exercising groups suggests the probability of a reduction in normal daily activities, which indicates the presence of compensation for the energy expended during exercise by a subsequent reduction in EE. In contrast, the elevated TEEx in the HP exercising groups (0·6 and 1·2 %P) argue against the presence of energy compensation. In conclusion, high dietary P decreases the body's capability to compensate for the energy deficit induced by E, consequently maintaining an elevated TEEx.

Dominant factors of the phosphorus regulatory network differ under various dietary phosphate loads in healthy individuals.

BACKGROUND: The purpose of this study was to explore the contribution of each factor of the phosphorus metabolism network following phosphorus diet intervention via Granger causality analysis. METHODS: In this study, a total of six healthy male volunteers were enrolled. All participants sequentially received regular, low-, and high-phosphorus diets. Consumption of each diet lasted for five days, with a 5-day washout period between different diets. Blood and urinary samples were collected on the fifth day of consumption of each diet at 9 time points (00:00, 04:00, 08:00, 10:00, 12:00, 14:00, 16:00, 20:00, 24:00) for measurements of serum levels of phosphate, calcium, PTH, FGF23, BALP, α-Klotho, and 1,25 D and urinary phosphorus excretion. Granger causality and the centrality of the above variables in the phosphorus network were analyzed by pairwise panel Granger causality analysis using the time-series data. RESULTS: The mean age of the participants was 28.5 ± 2.1 years. By using Granger causality analysis, we found that the α-Klotho level had the strongest connection with and played a key role in influencing the other variables. In addition, urinary phosphorus excretion was frequently regulated by other variables in the network of phosphorus metabolism following a regular phosphorus diet. After low-phosphorus diet intervention, serum phosphate affected the other factors the most, and the 1,25 D level was the main outcome factor, while urinary phosphorus excretion was the most strongly associated variable in the network of phosphorus metabolism. After high-phosphorus diet intervention, FGF23 and 1,25 D played a more critical role in active regulation and passive regulation in the Granger causality analysis. CONCLUSIONS: Variations in dietary phosphorus intake led to changes in the central factors involved in phosphorus metabolism.

Acute effects of dietary phosphorus intake on markers of mineral metabolism in hemodialysis patients: post hoc analysis of a randomized crossover trial.

BACKGROUND: Long-term dietary phosphorus excess influences disturbances in mineral metabolism, but it is unclear how rapidly the mineral metabolism responds to short-term dietary change in dialysis populations. METHODS: This was a post hoc analysis of a randomized crossover trial that evaluated the short-term effects of low-phosphorus diets on mineral parameters in hemodialysis patients. Within a 9-day period, we obtained a total of 4 repeated measurements for each participant regarding dietary intake parameters, including calorie, phosphorus, and calcium intake, and markers of mineral metabolism, including phosphate, calcium, intact parathyroid hormone (iPTH), intact fibroblast growth factor 23 (iFGF23), and C-terminal fibroblast growth factor 23 (cFGF23). The correlations between dietary phosphorus intake and serum mineral parameters were assessed by using mixed-effects models. RESULTS: Thirty-four patients were analyzed. In the fully adjusted model, we found that an increase in dietary phosphorus intake of 100 mg was associated with an increase in serum phosphate of 0.3 mg/dL (95% confidence intervals [CI], 0.2-0.4, p < .001), a decrease in serum calcium of 0.06 mg/dL (95% CI, -0.11 to -0.01, p = .01), an increase in iPTH of 5.4% (95% CI, 1.4-9.3, p = .01), and an increase in iFGF23 of 5.0% (95% CI, 2.0-8.0, p = .001). Dietary phosphorus intake was not related to cFGF23. CONCLUSIONS: Increased dietary phosphorus intake acutely increases serum phosphate, iPTH, and iFGF23 levels and decreases serum calcium levels, highlighting the important role of daily fluctuations of dietary habits in disturbed mineral homeostasis in hemodialysis patients.

Reduced phosphorus intake throughout gestation and lactation of sows is mitigated by transcriptional adaptations in kidney and intestine.

BACKGROUND: The environmental impact of pig farming need to be reduced, with phosphorus (P) being of particular interest. Specified dietary regimens and management systems contribute to meet environmental concerns and reduce economic constrains. However, pregnant and lactating sows represent vulnerable individuals, whose reproductive potential and metabolic health status relies on adequate supply of macro- and micronutrients. The aim of this study was to investigate, whether sows fed with a dietary P content that is below or above current recommendations are capable to maintain mineral homeostasis during the reproduction cycle and which endogenous mechanisms are retrieved therefore in kidney and jejunum. Nulliparous gilts were fed iso-energetic diets with recommended (M), reduced (L), or high (H) amounts of mineral P supplements throughout gestation and lactation periods. Blood metabolites and hormones referring to the P homeostasis were retrieved prior to term (110 days of gestation) and at weaning (28 days of lactation). Transcriptional responses in kidney cortex and jejunal mucosa were analyzed using RNA sequencing. RESULTS: The variable dietary P content neither led to an aberration on fertility traits such as total weaned piglets nor to an effect on the weight pattern throughout gestation and lactation. Serum parameters revealed a maintained P homeostasis as reflected by unaltered inorganic P and calcium levels in L and H fed groups. The serum calcitriol levels were increased in lactating L sows. The endocrine responses to the dietary challenge were reflected at the transcriptional level. L diets led to an increase in CYP27B1 expression in the kidney compared to the H group and to an altered gene expression associated with lipid metabolism in the kidney and immune response in the jejunum. CONCLUSIONS: Our results suggest that current P requirements for gestating and lactating sows are sufficient and over supplementation of mineral P is not required. Shifts in renal and jejunal expression patterns between L and H groups indicate an affected intermediate metabolism, which long-term relevance needs to be further clarified.

Dietary Phosphorus to Protein Ratio for the Mexican Population with Chronic Kidney Disease.

OBJECTIVE: Hyperphosphatemia is a major contributor to poor outcomes among cases of chronic kidney disease. Considering that foods with high protein content are major sources of phosphorus, a more suitable dietary phosphorus measure is the phosphorus to protein ratio. However, Mexican phosphorus to protein ratio tables do not exist. This article aims to estimate the phosphorus to protein ratio in foods commonly used by the Mexican population and to establish its usefulness in the selection of foods for patients with chronic kidney disease. METHODS: Six tables with the phosphorus to protein ratio were developed from different data sources concerning Mexican animal food composition. RESULTS: Egg whites have the best phosphorus to protein ratio. Partially skimmed milk has the lowest ratio among dairy products. Dairy products have high phosphorus to protein ratio variability. Red meat products have a ratio with an average of 9 mg/g. The phosphorus to protein ratio varies considerably for seafood (1.2-38.3 mg/g). CONCLUSIONS: The phosphorus to protein ratio could be a good strategy to choose each food during chronic kidney disease dietary treatment for the Mexican population.

Soymilk intake has desirable effects on phosphorus and calcium metabolism.

The objective was to evaluate the effect of replacing milk with soymilk or calcium-fortified soymilk as a part of a meal on postprandial serum phosphorus levels. This study had a randomized crossover design. Ten healthy subjects were enrolled and consumed three test meals that contained either milk, soymilk, or calcium-fortified soymilk containing the same amount of calcium as milk. Blood samples were collected at 0, 30, 60, 120, 240 and 360 min and urine samples were collected from 0 to 360 min after consuming the test meal. Serum phosphorus levels decreased the most after the ingestion of the soymilk meal, and the least after the ingestion of the milk meal. After the ingestion of each meal, serum intact parathyroid hormone levels showed an initial drop followed by a gradual rise, and these changes were more pronounced for the soymilk meal than for the milk meal and the soymilk + calcium meal. Our study shows that replacing milk with soymilk as a part of a meal may suppress the postprandial elevation in serum phosphorus levels, even when the soymilk contains the same amount of calcium as milk.

Dietary Food-Additive Phosphate and Human Health Outcomes.

Dietary intake of phosphorus is required for human health, and dietary reference intakes for phosphorus have been established. Food-grade phosphates are used as additives to provide a wide range of technical functions in food production. Phosphates are often the most efficient ingredients to provide the required functionality in many applications, and in some cases, there are not effective and approved alternatives. However, many investigators have expressed concern about the quantities of phosphorus and food-additive phosphate present in the diets of many populations. This paper presents the outcome of an extensive review of 110 primary research articles focused on identifying evidence that substantiates or refutes associations of total dietary phosphorus and food-additive phosphate intake with health and disease in humans. The lack of conclusive evidence prevented the drawing of firm conclusions about the safety and possible risks of food-additive phosphate in the general population, which is consonant with the overall assessments of authoritative institutions who have concluded that available data are insufficient to make the required determinations. Despite the inadequacy of the evidence currently available, many of the authors of the publications reviewed for this paper expressed concerns about the quantities of phosphorus and food-additive phosphate in the diets of the populations and subpopulations they studied. At the same time, most of these authors offered only qualified conclusions and expressed themselves tentatively. In addition, authors of primary research publications, authors of review articles, and authoritative institutions have called for the conduct of further research.

Availability of 24-h urine collection method on dietary phosphorus intake estimation.

Accurate assessment of dietary phosphorus intake is necessary to prevent hyperphosphatemia. The aim of this study was to evaluate the 24-h urine collection method for estimation of phosphate intake in healthy males. Two experiments, a 1-day and a 5-day loading test, were performed. After an overnight fast, subjects consumed test meals, 24-h urine collection was performed, and blood samples were obtained. In the 5-day loading test, a phosphorus supplement was orally administered on day 3. The association between the phosphorus content of test meals and urinary excretion, anthropometric indices, and blood biomarkers was analyzed to develop a more precise formula for estimating phosphorus intake. In the 1-day loading test, the standard deviation of predictive phosphorus intake, based on multiple linear regression analysis, was less than that for the phosphorus absorption rate. In the 5-day loading test, urinary phosphorus excretion was similar on days 2, 4 and 5, but was significantly higher on day 3 after phosphorus supplementation. Our results indicate that estimation of dietary phosphorus intake with the 24-h urine collection method, using the amount of phosphorus and urea nitrogen excretion, may increase the precision of short-term monitoring.

The New Nordic Diet: phosphorus content and absorption.

PURPOSE: High phosphorus content in the diet may have adverse effect on cardiovascular health. We investigated whether the New Nordic Diet (NND), based mainly on local, organic and less processed food and large amounts of fruit, vegetables, wholegrain and fish, versus an Average Danish Diet (ADD) would reduce the phosphorus load due to less phosphorus-containing food additives, animal protein and more plant-based proteins. METHODS: Phosphorus and creatinine were measured in plasma and urine at baseline, week 12 and week 26 in 132 centrally obese subjects with normal renal function as part of a post hoc analysis of data acquired from a 26-week controlled trial. We used the fractional phosphorus excretion as a measurement of phosphorus absorption. RESULTS: Mean baseline fractional phosphorus excretion was 20.9 ± 6.6 % in the NND group (n = 82) and 20.8 ± 5.5 % in the ADD group (n = 50) and was decreased by 2.8 ± 5.1 and 3.1 ± 5.4 %, respectively, (p = 0.6) at week 26. At week 26, the mean change in plasma phosphorus was 0.04 ± 0.12 mmol/L in the NND group and -0.03 ± 0.13 mmol/L in the ADD group (p = 0.001). Mean baseline phosphorus intake was 1950 ± 16 mg/10 MJ in the NND group and 1968 ± 22 mg/10 MJ in the ADD group and decreased less in the NND compared to the ADD (67 ± 36 mg/10 MJ and -266 ± 45 mg/day, respectively, p < 0.298). CONCLUSION: Contrary to expectations, the NND had a high phosphorus intake and did not decrease the fractional phosphorus excretion compared with ADD. Further modifications of the diet are needed in order to make this food concept beneficial regarding phosphorus absorption.

"Dietaly": practical issues for the nutritional management of CKD patients in Italy.

Evidence exists that nutritional therapy induces favorable metabolic changes, prevents signs and symptoms of renal insufficiency, and is able to delay the need of dialysis. Currently, the main concern of the renal diets has turned from the efficacy to the feasibility in the daily clinical practice.Herewith we describe some different dietary approaches, developed in Italy in the last decades and applied in the actual clinical practice for the nutritional management of CKD patients.A step-wise approach or simplified dietary regimens are usually prescribed while taking into account not only the residual renal function and progression rate but also socio-economic, psychological and functional aspects.The application of the principles of the Mediterranean diet that covers the recommended daily allowances for nutrients and protein (0.8 g/Kg/day) exert a favorable effect at least in the early stages of CKD. Low protein (0.6 g/kg/day) regimens that include vegan diet and very low-protein (0.3-0.4 g/Kg/day) diet supplemented with essential amino acids and ketoacids, represent more opportunities that should be tailored on the single patient's needs.Rather than a structured dietary plan, a list of basic recommendations to improve compliance with a low-sodium diet in CKD may allow patients to reach the desired salt target in the daily eating.Another approach consists of low protein diets as part of an integrated menu, in which patients can choose the "diet" that best suits their preferences and clinical needs.Lastly, in order to allow efficacy and safety, the importance of monitoring and follow up of a proper nutritional treatment in CKD patients is emphasized.

Characterizing and evaluating the expression of the type IIb sodium-dependent phosphate cotransporter (slc34a2) gene and its potential influence on phosphorus utilization efficiency in yellow catfish (Pelteobagrus fulvidraco).

A sodium-dependent phosphate cotransporter gene, NaPi-IIb (slc34a2), was isolated from yellow catfish (Pelteobagrus fulvidraco) intestine through homology cloning and the rapid amplification of cDNA ends. The full-length cDNA of slc34a2 consisted of 2326 bp with an open reading frame encoding 621 amino acids, a 160-bp 5' untranslated region, and a 300-bp 3' untranslated region. The deduced amino acid sequence showed 79.0 and 70.9% sequence identity to Astyanax mexicanus and Pundamilia nyererei, respectively. The membrane-spanning domains based on the hydrophilic and hydrophobic properties of the deduced amino acids were predicted, and results showed that the putative protein had eight transmembrane domains, with the intracellular NH2 and COOH termini. Two functional regions including first intracellular loop and third extracellular loop as well as the six N-glycosylation sites in second extracellular loop were found. The slc34a2 mRNA in the tested tissues was examined through semiquantitative reverse transcription polymerase chain reaction and quantitative real-time PCR, with the highest level found in the anterior intestine, followed by the posterior and middle intestines. The slc34a2 mRNA expression in the whole intestine under different dietary phosphorus (P) treatments was detected using qPCR. The results showed that the slc34a2 expression levels in the low-P groups (0.33 and 0.56%) were significantly higher (p < 0.05) than levels in the sufficient-P (0.81%) and high-P (1.15, 1.31, and 1.57%) groups. High expression of slc34a2 mRNA in low-P groups stimulated P utilization efficiency, indicating the close relationship between genotype and phenotype in yellow catfish. In contrast with conventional strategies (formula and feeding strategies), this study provided another possible approach by using molecular techniques to increase the P utilization in yellow catfish.

Fluctuating plasma phosphorus level by changes in dietary phosphorus intake induces endothelial dysfunction.

High serum phosphorus (P) impairs endothelial function by increasing oxidative stress and decreasing nitric oxide production. Serum P levels fluctuate due to circadian rhythms or dietary P intake in healthy people and due to dialysis in end-stage chronic kidney disease patients. Here we examined whether fluctuating plasma P caused by changes in dietary P intake may be involved in endothelial dysfunction, resulting in increased cardiovascular risk. Rats were fed a diet containing 0.6% P for 16 days (control group), or a diet alternating between 0.02% P and 1.2% P (LH group) or between 1.2% P and 0.02% P (HL group) every 2 days; the total amount of P intake among the groups during the feeding period was similar. In the LH and HL groups, endothelial-dependent vasodilation significantly decreased plasma 8-(OH)dG level significantly increased, and the expression of inflammatory factors such as MCP-1 increased in the endothelium as compared with the control group. These data indicate that repetitive fluctuations of plasma P caused by varying dietary P intake can impair endothelial function via increased oxidative stress and inflammatory response. Taken together, these results suggest that habitual fluctuation of dietary P intake might be a cause of cardiovascular disease through endothelial dysfunction, especially in chronic kidney disease patients.

Estimate of dietary phosphorus intake using 24-h urine collection.

Increases in serum phosphorus levels and dietary phosphorus intake induces vascular calcification, arterial sclerosis and cardiovascular diseases. Limiting phosphorus intake is advisable, however, no assessment methods are capable of estimating dietary phosphorus intake. We hypothesized that urinary phosphorus excretion can be translated into estimation of dietary phosphorus intake, and we evaluated whether a 24-h urine collection method could estimate dietary phosphorus intake. Thirty two healthy subjects were recruited for this study. Subjects collected urine samples over 24 h and weighed dietary records. We calculated dietary protein intake and phosphorus intake from dietary records and urine collection, and investigated associations between the two methods in estimating protein and phosphorus intake. Significant positive correlations were observed between dietary records and UC for protein and phosphorus intake. The average intakes determined from dietary records were significantly higher than from urine collection for both protein and phosphorus. There was a significant positive correlation between both the phosphorus and protein difference in dietary records and urine collection. The phosphorus-protein ratio in urine collection was significantly higher than in dietary records. Our data indicated that the 24-h urine collection method can estimate the amount of dietary phosphorus intake, and the results were superior to estimation by weighed dietary record.

Early manifestation of hypophosphatemic rickets in goslings: a potential role of insufficient muscular adenosine triphosphate in motility impairment of early P-deficient geese.

We aimed to determine the onset time of hypophosphatemic rickets and investigate the mechanism of motility impairment through adenosine triphosphate (ATP) production in goslings. Two hundred and sixteen 1-day-old male Jiangnan white geese were randomly divided into 3 groups, with 6 replicates and 12 geese per replicate. Birds were fed on 3 diets: a control diet (nonphytic phosphorus, NPP, 0.38%), a P-deficient diet (PD; NPP, 0.08%), and a high P diet (HP; NPP, 0.80%) for 14 d. Subsequently, all birds were shifted to the control diet for an additional 14 d. The cumulative incidence of lameness increased significantly (P < 0.01) starting on d 4, reaching over 80% on d 7 and 100% on d 12 in the PD group. Drinking and eating frequency decreased from d 4 and d 5, respectively, in the PD group compared to the other groups (most P < 0.01). The PD group exhibited shorter and narrower beaks, higher (worse) curvature scores of the beak and costochondral junctions, swelling caput costae, and dirtier feathers since d 4, in contrast to the control and HP groups (most P < 0.01). The HP had bigger (P < 0.05) beak and sternum sizes than the control groups on d 4 to 11. Leg muscle ATP levels were lower (P < 0.01 or 0.05) on d 4 to 11; in contrast, adenosine diphosphate (d 7-11) was higher in PD compared to the control (P < 0.05). Leg muscle ATP level had positive linear (R2 > 0.40) correlations (r > 0.60) with eating and drinking frequencies on d 7 and 11 (P < 0.01). Bone stiffness, feather cleanliness, and ATP levels recovered (P > 0.05) to the control level, whereas bone size did not recover (P < 0.05) in PD and HP after eating the control diet for 2 wk. The onset time of hypophosphatemic rickets was around 4 d in goslings, and insufficient leg muscle ATP was related to the impaired motility observed in early P-deficient geese.

Phosphorus Knowledge and Dietary Intake of Phosphorus of US Adults Undergoing Dialysis.

Abnormal serum phosphorus is a concern for adults undergoing dialysis due to the risk for mortality and morbidity. General recommendations for maintaining serum phosphorus within normal limits is monitoring dietary intake of phosphorus and taking phosphate binders, as prescribed. However, limited research is available about adults' phosphorus knowledge and dietary intake of phosphorus. The purpose of this cross-sectional study was to determine the association between phosphorus knowledge and dietary intake of phosphorus of adults on dialysis. An online Qualtrics survey was conducted during February-September 2023. Participants (n = 107) responded to the 74-item questionnaire (30-day food frequency questionnaire, phosphorus knowledge questionnaire, and demographic questions). Analysis included frequencies, descriptive statistics, t-tests, and Spearman correlations. JMP SAS v16 was used with a statistical significance of p < 0.05. Of the participants, 57.0% (n = 61) were on peritoneal dialysis and 43.0% (n = 46) were on hemodialysis. Average phosphorus knowledge score was 10.6 ± 3.0 out of 19 or 55.8%, with those on peritoneal dialysis having lower scores (54.7%) compared to participants on hemodialysis (58.1%) (p < 0.05). The daily average dietary phosphorus intake was 605 ± 297 mg. Participants on peritoneal dialysis consumed more phosphorus (625 mg) compared to participants on hemodialysis (576 mg) (p < 0.05). There was no association with phosphorus knowledge scores and dietary intake of phosphorus. There were positive correlations between discussing about phosphorus, knowing serum phosphorus concentration, and phosphorus knowledge scores. These results can aid practitioners in providing tailored nutrition education among adults on dialysis.