Dietary Phosphorus Research Articles

Effects of a Low Phosphorus Diet on Phosphorus and Calcium Whole-Body Balance and Intestinal Absorption: Results of a Pilot Study in Adults with Moderate CKD

Effects of a Low Phosphorus Diet on Phosphorus and Calcium Whole-Body Balance and Intestinal Absorption: Results of a Pilot Study in Adults with Moderate CKD

256 Evaluation Calcium and Phosphorus Ratios in the Presence of Phytase on Performance and Whole-Body Bone Mineralization in Growing Pigs

Abstract The objective of this study was to evaluate the effects of dietary calcium and phosphorus ratios in the presence of super dose phytase on grower pigs growth performance and bone mineral density. In two replicates, a total of 48 mixed sex pigs (26.7 kg BW) were allotted by BW and sex into individual pens across 3 dietary treatments (16 pigs/treatment) for 28 days. All diets contain phytase at 1,500 FTU/kg of complete feed and the three diet treatments were formulated with differing levels of Ca to achieve 0.7, 1.1 and 1.5 total Ca:total P. All diets were formulated to be isocaloric and isonitrogenous and ratios were achieved by vary limestone and sand. Pig BW and feed disappearance were recorded at the start (d 0) and end (d 28) of the study to calculate ADG, ADFI and G:F. On day 28, all pigs were euthanized to determine whole body bone, foot, rib, femur and tibia bone mineral density via dual x-ray absorptiometry. Data were analyzed with pen as the experimental unit, fixed effect of dietary treatment, sex and their interaction, and initial BW block and repartition as random effects. Differences were determined significant at P ≤ 0.05. Pig ADG was increased in the 1.1 verses 0.7 and 1.5 Ca:P diets (1.01, 0.95 and 0.95 kg/d, respectively, P = 0.046). End body weight was not different in the 0.7, 1.12 and 1.5 Ca:P treatments (53.5, 54.8 and 53.1 kg, respectively, P = 0.106). Diet Ca:P ratio did not alter ADFI or G:F. Whole body, tibia and femur bone mineral density was increased by 110% in 1.5 verses 0.7 Ca:P fed pigs, with bone mineral density being intermediated in the 1.1 Ca:P diets. Whole body (0.740, 0.752, 0.797, g/cm2, for 0.7, 1.1 and 1.5 Ca:P respectively, P = 0.033). For 0.7, 1.1 and 1.5 Ca:P femurs, bone mineral density was 0.463, 0.498 and 0.516, respectively, P = 0.034). Dietary treatment did not alter whole foot or 10th rib bone mineral densities (P > 0.05). Sex did not affect pig performance, but gilts had a 9% increase in bone mineral content. In conclusion, formulating dietary Ca:P in the presence of super dosing phytase at 1.1:1 total Ca:P resulted in the best ADG, but a ratio of 1.5:1 had the greatest bone mineral density.

273 Dynamics of Bone Mineralization in Primiparous Sows as a Function of Dietary Phosphorus and Calcium During Lactation

Abstract In a context of maximizing the use of dietary phosphorus (P) in swine production, research should focus on understanding the mechanisms of bone P and calcium (Ca) utilization in sows. A better knowledge of P and Ca quantities that can be mobilized from bones during lactation, which would then be restored during gestation, would allow the development of new feeding strategies including this dynamic process. In turn, it can lead to a substantial decrease in dietary P supply. The role of dietary phytase supplementation also needs to be quantified in such potential strategies. In addition to the bone mineral status of sows, the consequences of these strategies on litter performance need to be documented. The objectives of the experiment were to measure the capacity of the sow to mobilize bone minerals reserves during lactation according to dietary digestible P (P dig) content and phytase addition, to restore them, during the following gestation, and to measure the effects on the growth performance of the offspring. Whole body bone mineral content (BMC) of primiparous Swiss Large White sows (n = 24) from the Agroscope sow herd was measured by dual-energy X-ray absorptiometry (DXA) on days 2, 14, 26, 66, and 106 after parturition. Four lactation diets were formulated to cover all nutritional requirements except for Ca and P dig: control without phytase (100%; 3.0 g P dig, 9.9 g Ca/kg), 75% of P dig without phytase (75%; 2.3 g P dig, 8.3 g Ca/kg), 50% of P dig without phytase (50; 1.5 g P dig, 6.0 g Ca/kg), and 50% of P dig with phytase (50+Phyt; 3.0 g P dig, 7.6 g Ca/kg). The gestation diet was formulated to cover nutritional requirements of Ca and P dig (2.6 g P dig, 8.2 g Ca/kg). Piglets were weighed at 1 and 14 days after parturition and at weaning (day 26), and the average daily gain (ADG) per piglet was calculated. During lactation, BMC of the sow (in g/kg of body weight, BW) tended to be less in treatment 50% than in treatment 100% (-12.8%, linear effect x time quadratic, P = 0.05). During gestation, BMC was similar between treatments. Therefore, sows in treatment 50% were able to recover their bone-mineralization deficit during the next gestation. The BMC (in g and in g/kg BW) was similar between treatments 100% and treatment 50+Phyt throughout the experimental period. Piglet weight at days 1, 14, and 26 and ADG (days 1 to 14, 14 to 26 and 1 to 26) were similar between dietary treatments. These results show the possibility of drastically reducing dietary P during lactation without decreasing litter performance and highlight the ability of primiparous sows to mobilize bone mineral during lactation and restore it during gestation.

Dietary non-phytate phosphorus requirements for optimal productive and reproductive performance, and egg and tibial quality in egg-type duck breeders

Optimal dietary non-phytate phosphorus (NPP) is essential in poultry to maximise productive and reproductive performance, along with indices of egg and bone quality. This study aimed to establish the NPP requirements of egg-type duck breeders aged from 54 to 80 weeks on the following traits: egg production, egg incubation, egg quality, tibial characteristics, reproductive organ, plasma indices, and the expression of genes related to phosphorus absorption. Longyan duck breeders aged 54 weeks (n = 300) were randomly allotted to five treatments, each containing six replicates of 10 individually caged birds. Birds were fed corn-soybean meal-based diets containing 0.18, 0.25, 0.32, 0.38, and 0.45% NPP/kg for 27 weeks. The tested dietary NPP levels did not affect egg production or egg quality indices. The hatchling weight of ducklings increased (quadratic, P < 0.01) as dietary NPP level increased, and the highest value occurred with 0.25% NPP. The number of large yellow follicles (LYF), and the relative weights of LYF and ovary showed linear and quadratic responses to dietary NPP levels; the lowest number and relative weight of LYF occurred with 0.38% NPP, and the lowest ovarian weight was obtained with 0.25% NPP. There were no differences in tibial length, breaking strength, and mineral density in response to dietary NPP levels. In contrast, tibial content of Ca increased (linear, P < 0.01) with dietary NPP levels increasing from 0.18 to 0.45%, and the tibial content of P increased at 0.32% NPP and the higher dietary NPP levels. Plasma concentration of P showed a quadratic (P < 0.05) response to the dietary NPP levels, where the highest value was seen at 0.38% NPP. In conclusion, dietary NPP levels from 0.18 to 0.45% had no effects on egg production, and egg and tibial quality of duck breeders. The duck breeders fed a diet with 0.25% NPP showed the highest hatchling weight of their offspring, while those fed 0.38% NPP had the lowest number and relative weight of LYF. These results indicated that the diet with 0.25% NPP can be used in egg-type duck breeders to improve the hatchling weight of their offspring, without adverse effects on their productivity. The regression model indicated that the maximal hatchling weight of ducklings was obtained from duck breeders fed the diet with 0.30% NPP.

Effects of Lower Dietary Calcium and Phosphorus on Growth Performance and Bone Mineralizatıon of Broilers

This experiment was carried out to investigate the effects of reduced dietary calcium (Ca) and non-phytate-phosphorus (NPP) levels at 2:1 constant ratio on performance, carcase parameters and bone mineralization of Ross-308 broilers. A total of 11400 one-day-old chicks were randomly allocated to five dietary treatments with twelve replicates and were fed starter diets including either recommended (control treatment, T1) or a 6.25% lower level of both Ca and NPP according to breeder’s recommendations during starter period (SP). After SP, control treatment (T1) continued to be provided through diets containing 0.87 and 0.78 % Ca for grower (GP) and finisher periods (FP), respectively, while 6.25 % reduced group was divided into 4 dietary treatments regarding extent of decrease in Ca and NPP levels and provided by diets containing 0.79;0.65 (T2), 0.79;0.60 (T3), 0.75;0.65 (T4), and 0.75;0.60 (T5) % Ca for GP and FP, respectively. After SP, moderate and even substantial reduction of Ca and NPP significantly decreased feed intake (FI) (quadratic, P&lt;0.05), but obtained similar body weight gain (BWG) and FCR compared to the control (P&gt;0.05). On the other hand, reduced dietary Ca through T1 to T5 significantly decreased the total Ca and NPP intake of broilers (linear and quadratic, P&lt;0.01), and accompanied to significant linear and quadratic relationship between Ca intake and FCR and BWG respectively. It can be concluded that reducing Ca level down to 0.75 and 0.60 % in grower and finisher phase, respectively are possible without compromising the growth performance and bone mineralization of modern broilers.

Longitudinal Assessment of Health-Related Quality of Life in Three Different Hyperphosphatemia Management Groups of Stage III and IV Chronic Kidney Disease Patients.

Health-related quality of life (HRQoL) has emerged as an important outcome measure inpatients with CKD. The lack of prospective studies on HRQoL and its relation with hyperphosphatemia control measures among pre-dialysis patients necessitated the need for this study. This is a prospective, randomized, controlled, open-labelled studythat was conducted for one year on 120 CKD stages III and IV patients divided equally into three groups: Group 1, in which patients under went dietary phosphorus modification; Group 2, in which they were administered calcium-based phosphate binders; and Group 3, in which they were administered non-calcium-based phosphate binders. Patients were assessed for HRQoL, fibroblast growth factor 23 (FGF 23), intact parathyroid hormone (iPTH), phosphorus, and nutritional status, and dietary phosphorus control strategies at 0, 6, and 12 months. HRQoL was measured by using the 36-item Short Form Survey (SF-36) that included a physical component score (PCS) and mental component score (MCS). The scores is ranging from 0 to 100. Higher scores indicate better health status. Usingthe two-wayand one-way repeated measure ANOVA, we analyzed equality of group means, time intervals, and interactions. At baseline, the mean PCS and MCS were equal in three groups. PCS improved significantly (P < 0.00) from baseline to one year in all the three groups: ingroup 1, the PCS score was 66.5 ± 13.5to 75.1 ± 9.76; in group 2, it was 68.9 ± 11.80 to 77.2 ± 7.50; and in group 3, it was 66.2 ± 12.16 to 73.8 ± 9.27. Initially, MCS declined substantially on the sixth month but recovered afterone year. Multiple regression analysis in 13 associated parameters yielded R2 of 13.7% and 18.1% in PCS and MCS, respectively, indicating little contribution of various parameters. There has been a significant positive change in PCSs in three hyperphosphatemia management groups over a period of 12 months. Among the three study groups, the incremental changes in PCS and MCS scores were insignificant.

The association between dietary mineral intake and the risk of preeclampsia in Chinese pregnant women: a matched case–control study

Previous studies on the relationship between dietary minerals and preeclampsia (PE) have given inconsistent results. The aim of this study was to further clarify the relationship between dietary minerals intake and PE in Chinese pregnant women. In this study, 440 pairs of hospital–based preeclamptic and healthy women were matched 1:1. Dietary intake was obtained through a 78–item semi–quantitative food frequency questionnaire. Multivariate conditional logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). Restricted cubic splines were plotted to evaluate the dose–response relationship between dietary minerals intake and PE. This study found significant inverse associations for dietary intake of calcium, magnesium, phosphorus, iron, copper, manganese and zinc and the risk of PE in both univariate and multivariate models (all P- trend < 0.05). After adjusting for possible confounders, compared with the lowest quartile, the odds ratio of the highest quartile was 0.74 (95% CI 0.56–0.98) for calcium, 0.63 (95% CI 0.42–0.93) for magnesium, 0.45 (95% CI 0.31–0.65) for phosphorus, 0.44 (95% CI 0.30–0.65) for iron, 0.72 (95% CI 0.53–0.97) for copper, 0.66 (95% CI 0.48–0.91) for manganese and 0.38 (95% CI 0.25–0.57) for zinc. In addition, a reverse J–shaped relationship between dietary minerals intake and PE risk was observed (P–overall association < 0.05). In Chinese pregnant women, a higher intake of dietary minerals, including calcium, magnesium, phosphorus, copper, iron, manganese, and zinc was associated with a lower odds of PE.

Effects of two phosphorous sources in the diet on the growth performance, digestibility, and plasma physiological parameters of Pelodiscus sinensis juveniles

Phosphorus is an essential mineral for aquatic animals to maintain the health of the skeletal system and many physiological functions. This study assessed the effects of two inorganic phosphorus sources on growth performance, apparent phosphorus digestibility, whole-body proximate composition, and physiological status in juvenile Pelodiscus sinensis. Two experimental diets were supplemented with 4% calcium phosphate monobasic (MCP) and 5.47% calcium phosphate dibasic (DCP), respectively, to obtain equal total dietary phosphorus (2.20%). 96 turtles (initial body weight: 5.40±0.03g) were randomly distributed into 12 tanks and fed the corresponding diets for 60d. Results showed that phosphorus sources have not significantly influenced the growth parameters, including the specific growth rate, feeding rate, and feed conversion ratio (P&gt;0.05). No significant differences were observed in the hepatosomatic index and whole-body proximate compositions between MCP and DCP groups (P&gt;0.05). The apparent digestibility coefficients of dry matter and phosphorus in MCP group (53.22%) are slightly higher than that in DCP group (48.98%) but did not reach the statistically significant level (P &gt; 0.05). Turtles in MCP and DCP groups are the same in plasma physiological parameters and have equal alkaline phosphatase activities in plasma and liver (P&gt;0.05). In conclusion, calcium phosphate monobasic and calcium phosphate dibasic had the same biological phosphorus availability in diet for juvenile Pelodiscus sinensis.

Influence of dietary phosphorus on orthophosphate accumulation in recirculating aquaculture systems with rainbow trout (Oncorhynchus mykiss)

Dietary phosphorus (P) levels affect the excretion of orthophosphate (PO4-P) from fish. Since most recirculating aquaculture systems (RAS) do not specifically remove PO4-P within the recirculating loop, dietary P levels may influence PO4-P concentrations in RAS water. A feeding trial was performed in freshwater RAS, aiming to determine the relationship between dietary P levels and PO4-P accumulation in RAS water, and to examine potential effects of dietary P levels on microbial activity and abundance in RAS water given that P is an essential mineral for all microorganisms. Three diets with 1.49% (HiP), 1.20% (MeP), and 0.89% (LoP) total P, respectively, were each fed to triplicate pilot-scale RAS with juvenile rainbow trout (Oncorhynchus mykiss) for five weeks, applying a daily feed loading of 1.67 kg feed/m3 make-up water. Digestible dietary P levels correlated significantly with the PO4-P concentrations in RAS water at the end of the trial, while no similar correlations with microbial abundance or activity were observed. Nitrate-N concentrations measured by the end of the trial matched predicted equilibrium concentrations. In contrast, measured PO4-P concentrations were approximately 40 – 50% lower than predicted regardless of diets, suggesting that PO4-P was likely utilized by RAS microbes. We therefore speculate whether lowering dietary P levels could become an effective tool for microbial management in RAS.

Effect of feeding kulthi seeds (Dolichos biflorus L.) with high calcium low phosphorus diet on induced/reduced urolithiasis and kidney damage in cockerel

Effect of feeding kulthi seeds (Dolichos biflorus L.) with high calcium low phosphorus diet on induced/reduced urolithiasis and kidney damage in cockerel

Addressing Phosphorus Waste in Open Flow Freshwater Fish Farms: Challenges and Solutions

Legislation and interest exists to protect and restore freshwater and marine ecosystems from the environmental impact of aquaculture. However, aquaculture-induced eutrophication remains a major environmental concern. Water soluble phosphorus, uneaten feed, feces, and metabolic waste from farmed fish increase phosphorus concentrations in adjacent waters. In open freshwater fish farms, in particular, the effects can be more immediate, as excess phosphorus is introduced directly into ecosystems. Several intestinal enzymes, transporters, and regulating factors have been implicated in farmed fish dietary phosphorus retention. For example, alkaline phosphatase and other transporters aid in the absorption of phosphorus in the anterior intestine, while pH, calcium, and vitamin D influence these enzymes and transporters. This process may also be influenced by intestinal morphology and the gut microbiome. To reduce phosphorus pollution from open flow fish farms, a thorough understanding of the processes that affect nutrient retention and absorption, as well as the impact of dietary factors, anti-nutritional substances, and intestinal morphology, is required. Aquaculture can be made more sustainable by reducing phosphorus release. This can be achieved by optimizing feed composition, adding functional feed ingredients, managing gut health, and treating effluent aquaculture waters with bioremediation and absorbing materials. Anti-nutritional factors can be mitigated through processing and through the use of functional feed additives. Addressing these issues will reduce aquaculture’s environmental impact, ensuring aquatic ecosystem health and global food security. In addition, treating effluent aquaculture waters with bioremediation and absorbing materials can remove phosphorus from the water, preventing it from entering the environment. This can further reduce the environmental impact of aquaculture and help to ensure the sustainability of this sector.

High Dietary Phosphorus Is Associated with Increased Breast Cancer Risk in a U.S. Cohort of Middle-Aged Women.

Research has shown that high amounts of dietary phosphorus that are twice the amount of the U.S. dietary reference intake of 700 mg for adults are associated with all-cause mortality, phosphate toxicity, and tumorigenesis. The present nested case-control study measured the relative risk of self-reported breast cancer associated with dietary phosphate intake over 10 annual visits in a cohort of middle-aged U.S. women from the Study of Women's Health Across the Nation. Analyzing data from food frequency questionnaires, the highest level of daily dietary phosphorus intake, >1800 mg of phosphorus, was approximately equivalent to the dietary phosphorus levels in menus promoted by the United States Department of Agriculture. After adjusting for participants' energy intake, this level of dietary phosphorus was associated with a 2.3-fold increased risk of breast cancer incidence compared to the reference dietary phosphorus level of 800 to 1000 mg, which is based on recommendations from the U.S. National Kidney Foundation, (RR: 2.30, 95% CI: 0.94-5.61, p = 0.07). Despite the lack of statistical significance, likely due to the small sample size of the cohort, the present nested case-control study's clinically significant effect size, dose-response, temporality, specificity, biological plausibility, consistency, coherence, and analogy with other research findings meet the criteria for inferred causality in observational studies, warranting further investigations. Furthermore, these findings suggest that a low-phosphate diet should be tested on patients with breast cancer.

A High-Phosphorus Diet Moderately Alters the Lipidome and Transcriptome in the Skeletal Muscle of Adult Mice.

A high phosphorus intake has been associated with various metabolic disorders, including chronic kidney disease, cardiovascular disease, and osteoporosis. Recent studies have demonstrated the effects of dietary phosphorus on lipid and glucose metabolism. This study investigated the impact of a high-phosphorus diet on mouse skeletal muscle lipid composition and gene transcription. Adult male mice (n = 12/group) received either a diet with an adequate (0.3%) or a high (1.2%) phosphorus concentration for 6 weeks. The lipidome analysis showed that among the 17 analyzed lipid classes, the concentrations of three classes were reduced in the high phosphorus group compared to the adequate phosphorus group. These classes were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and lysophosphatidylcholine (LPC) (p < 0.05). Out of the three hundred and twenty-three individual lipid species analyzed, forty-nine showed reduced concentrations, while three showed increased concentrations in the high phosphorus group compared to the adequate phosphorus group. The muscle transcriptome analysis identified 142 up- and 222 down-regulated transcripts in the high phosphorus group compared to the adequate phosphorus group. Gene set enrichment analysis identified that genes that were up-regulated in the high phosphorus group were linked to the gene ontology terms "mitochondria" and "Notch signaling pathway", whereas genes that were down-regulated were linked to the "PI3K-AKT pathway". Overall, the effects of the high-phosphorus diet on the muscle lipidome and transcriptome were relatively modest, but consistently indicated an impact on lipid metabolism.

Increased Slc34a2 expression and paracellular phosphate permeability contribute to high intestinal phosphate absorption in young mice.

Phosphorus is a critical constituent of bone as a component of hydroxyapatite. Bone mineral content accrues rapidly early in life necessitating a positive phosphorus balance, which could be established by a combination of increased renal reabsorption and intestinal absorption. Intestinal absorption can occur via a transcellular pathway mediated by the apical sodium-phosphate cotransporter, Slc34a2/NaPiIIb or via the paracellular pathway. We sought to determine how young mammals increase dietary phosphorus absorption from the small intestine to establish a positive phosphorus balance, a prerequisite for rapid bone growth. The developmental expression profile of genes mediating phosphate absorption from the small intestine was determined in mice by qPCR and immunohistochemistry. Additionally, Ussing chamber studies were performed on small bowel of young (p7-p14) and older (8- to 17-week-old) mice to examine developmental changes in paracellular Pi permeability and transcellular Pi transport. Blood and urinary Pi levels were higher in young mice. Intestinal paracellular phosphate permeability of young mice was significantly increased relative to older mice across all intestinal segments. NaPiIIb expression was markedly increased in juvenile mice, in comparison to adult animals. Consistent with this, young mice had increased transcellular phosphate flux across the jejunum and ileum relative to older animals. Moreover, transcellular phosphate transport was attenuated by the NaPiIIb inhibitor NTX1942 in the jejunum and ileum of young mice. Our results are consistent with young mice increasing phosphate absorption via increasing paracellular permeability and the NaPiIIb-mediated transcellular pathway.

45. Dynamics of bone mineralization in primiparous sows as a function of dietary phosphorus and calcium during lactation

45. Dynamics of bone mineralization in primiparous sows as a function of dietary phosphorus and calcium during lactation

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, mineralizationand 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, 7.5and 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 6.5and 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, bonesand 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, bonesand 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.

Fishmeal replacement and its effects on nutrition and the physiology of Penaeus vannamei shrimp juveniles

The replacement of fishmeal with plant protein sources has been studied in Penaeus vannamei. However, it has only been studied from the point of view of protein replacement, forgetting the integral role that fishmeal plays in the nutrition of shrimp. This study aimed to determine if a supplement of dietary phosphorus can sustain the fishmeal replacement by a blend of plant protein feedstuffs, with betaine and tauren as attractants and still supporting homeostasis, growth, digestive enzymes, and lipid-soluble antioxidant systems at normal levels in juveniles of P. vannamei. A standard feed (25% fishmeal) for juvenile P. vannamei was partially replaced with a mix of plant ingredients (soybean and canola paste, soy protein concentrate, and wheat meal). These feedstuffs were supplemented with amino acids (MET, LYS, TAU) plus microencapsulated exogenous phytase, betaine, and dicalphosphate. P. vannamei juveniles (2.56 g) were maintained in 100 L fiber tanks for 70 days. Biomass was significantly affected by the treatments (P &lt; 0.05), being better as the fishmeal was replaced in the diet and comparable to commercial feed. No significant changes were observed in blood parameters. Muscle superoxide dismutase activity was significantly affected by the diets (P &lt; 0.05). There were adaptive changes in digestive enzymes, and homeostasis remained stable. Fishmeal replacement may depend on supplementation with taurine and soluble phosphorus, not only for performance but flesh quality, and here, the shear strength of the shrimp muscle remained within the acceptable value (69-81 mJ).

A first model of the fate of dietary calcium and phosphorus in broiler chickens

To reduce P excretion and increase the sustainability of poultry farms, one needs to understand the mechanisms surrounding P metabolism and its close link with Ca metabolism to precisely predict the fate of dietary P and Ca and related requirements for birds. This study describes and evaluates a model developed to estimate the fate of Ca and P consumed by broilers. The Ca and P model relies on three modules: (1) digestion of Ca and P; (2) dynamics of Ca and P in soft tissue and feathers; and (3) dynamics of body ash. Exogenous phytase affects the availability of Ca and P; thus, to predict the absorption of those minerals, the model also accounts for the effect of phytase on Ca and P digestibility. We used a database to estimate the consequences of dietary Ca, P, and phytase over feed intake response. This study followed a four-step process: (1) Ca and P model development and its coupling with a growth broiler model; (2) model behavior assessment; (3) sensitivity analysis to identify the most influential parameters; and (4) external evaluation based on three databases. The proportion of P in body protein and the Ca to P ratio in bone are the most sensitive parameters of P deposition in soft tissue and bone, representing 91 and 99% of the total variation. The external evaluation results indicated that body water and protein had an overall mean square prediction error (rMSPE) of 7.22 and 12.3%, respectively. The prediction of body ash, Ca, and P had an rMSPE of 7.74, 11.0, and 6.56%, respectively, mostly errors of disturbances (72.5, 51.6, and 90.7%, respectively). The rMSPE for P balance was 13.3, 18.4, and 22.8%, respectively, for P retention, excretion, and retention coefficient, with respective errors due to disturbances of 69.1, 99.9, and 51.3%. We demonstrated a mechanistic model approach to predict the dietary effects of Ca and P on broiler chicken responses with low error, including detailed simulations to show the confidence level expected from the model outputs. Overall, this model predicts broilers’ response to dietary Ca and P. The model could aid calculations to minimize P excretion and reduce the impact of broiler production on the environment. A model inversion is ongoing that will enable the calculation of Ca and P dietary quantities for a specific objective. This will simplify the use of the model and the feed formulation process.

Dietary exogenous phytase improve egg quality, reproductive hormones, and prolongs the lifetime of the aging Hy-Line brown laying hens fed nonphytate phosphorus

The study examined how adding phytase to nonphytate phosphorus (NPP) diets affected performance, egg quality, reproductive hormones, and plasma biochemical indices in 73- to 80-wk-old laying hens. Six treatments with 5 replicates of 18 Hy-Line brown laying hens each were randomly assigned. Three isonitrogenous, isocaloric diets containing consistent calcium levels (3.8%) were formulated to contain 0.20, 0.25, and 0.30% NPP, treated with or without phytase supplementation (1,000 FYT per kg feed, Ronozyme HiPhos-L, Aspergillus oryzae 6-phytase). The results showed that the addition of phytase to the diet containing 0.20, 0.25, and 0.30% NPP increased egg production by 1.50, 1.64, and 0.97%, respectively, and improved eggshell thickness. Also, use of phytase in the diet contain 0.25, and 0.30% NPP increased the plasma concentration of albumin (ALB), high-density lipoprotein (HDL), phosphorus (P), and plasma follicle-stimulating hormone (FSH), plasma calcium (Ca), estradiol-17β (E2β), and luteinizing hormone (LH). In contrast, the egg weight, feed intake, egg mass, feed conversion ratio, albumen height, Haugh unit, yolk, and shell color were unaffected. It can be advisable to use phytase supplementation in an elderly laying hen's diet contain 0.25, and 0.30% NPP to improve shell quality and positively impact reproductive hormones leading to the persistence of egg production.

#2971 LONG-TERM EFFECTS OF THE NEW NORDIC RENAL DIET ON PHOSPHOROUS HOMEOSTASIS IN PATIENTS WITH CHRONIC KIDNEY DISEASE STAGE 3 AND 4

Abstract Background and Aims Chronic kidney disease (CKD) causes severe disturbances in phosphate metabolism. The New Nordic Renal Diet (NNRD) is a whole food approach designed by our group, with low dietary phosphorus content (850 mg/day). In a 1-week study, NNRD had positive effects on phosphorus homeostasis in patients with CKD stage 3-4 [1]. The aim of the present study was to examine the long-term health effects of a dietary intervention with NNRD in patients with CKD stage 3-4 [2]. Method A 26-week randomized, controlled, non-blinded trial comparing the effect of NNRD vs. non-restricted habitual diet. Patients in the NNRD group received weekly home delivery of fresh food items (free of charge) and recipes for five days of the week, and on the remaining two days they were instructed to prepare meals according to the NNRD food principles. The study was designed with seven follow-up visits in the outpatient clinic where fasting blood samples and 24-hour urine collection were delivered. Linear mixed-effects models were used to assess the effects of the intervention, time, and the potential interaction between intervention and time. The primary endpoint was the difference in 24-hour urine phosphorus excretion between the two study groups. Secondary endpoints included fractional phosphorus excretion and plasma fibroblast growth factor 23 (p-FGF23). Results Sixty patients (mean age 54 years, 31 women) with mean eGFR of 34 ml/min/1.73 m2 were included. Two patients were withdrawn due to dialysis initiation. In the NNRD-group (n = 29), mean 24-hour urine phosphorus excretion during the intervention period was 651 mg (SD, 35 mg) vs. 930 mg (SD, 84 mg) in the control group (n = 29), between-group difference 279 (95% CI; -372, -91; P &amp;lt; 0.001) (Figure 1). Mean fractional phosphorus excretion was 11% (SD, 5%) in the NNRD-group and 14% (SD, 7%) in the control group, between-group difference 3% (95% CI; -6.4, -0.8; P = 0.01). Mean p-FGF23 was 162 pg/ml (SD, 130 pg/ml) in the NNRD-group and 215 pg/ml (SD, 230 pg/ml) in the control group, between-group difference 52 pg/ml (95% CI; -100, 73; P = 0.03). P-urea was 3.4 mmol/L lower in the NNRD group (95% CI; -5.3, -0.2, P = 0.03). P-albumin was 1.1 g/L higher in the NNRD group (95% CI; 0.02, 2.4; P = 0.04) and 24-h urine bicarbonate excretion was 4.1 mmol higher in the NNRD group (95% CI; 0.7, 7.5, P = 0.01). There was no difference between study groups in p-phosphorous, p-creatinine, p-potassium, p-calcium, p-lipids, or proteinuria. Conclusion NNRD intervention in the context of fresh food delivery and recipes was feasible and had a major beneficial effect on phosphorous parameters in patients with CKD 3-4.