Dietary Phosphorus Research Articles

Interactive effects of calcium, vitamin D3, and exogenous phytase on phosphorus utilization in male broiler chickens from 1 to 21 days post-hatch: A meta-analysis approach

Provision of appropriate dietary phosphorus (P) content considering environmental and economic aspects has been challenging for poultry nutritionists during the last decades. For this reason, many studies have focused on factors affecting P utilization in broiler chickens, such as calcium (Ca), cholecalciferol (vitamin D3; VD), and exogenous phytase (EP), but their results have sometimes been accompanied by inconsistencies. Therefore, comprehensive knowledge of the factors affecting P utilization and their interactions is required to draw conclusions from the available results. For this purpose, a meta-analysis was conducted using 79 studies including 719 experimental treatments published between 2011 and 2021, which considered the effects of Ca, EP, and VD on P utilization in male broiler chickens from 1 to 21 days post-hatch. The collected data were fitted well to a mixed model for average daily gain (ADG; R2 = 0.941), average daily feed intake (ADFI; R2 = 0.956), feed conversion ratio (FCR; R2 = 0.989), and tibia ash (TA) content (R2 = 0.984). Linear and quadratic effects of dietary non-phytate P (NPP) content on ADG, ADFI, FCR, and TA content were observed (P < 0.001). Also, results showed the linear and quadratic effects of EP on ADG, FCR, and TA content (P < 0.001). The ADG (P < 0.01) and TA content (P < 0.05) were affected by VD supplementation. The fitted models showed that the increase in dietary Ca content linearly exacerbated all responses (P < 0.001), but such negative effects were alleviated with the increase in dietary NPP content and EP and, or VD addition due to their interactions. Results of the optimization process showed that simultaneous addition of EP and VD resulted in lower NPP concentration required to optimize growth performance and TA content compared to separate supplementation. Also, increasing dietary level of EP (up to 2000 FTU/kg of diet) reduced NPP requirement for optimal growth performance and bone mineralization. It can be concluded that Ca, EP, and VD affect the NPP requirements of broiler chickens, but the magnitude of these effects varies depending on the studied criterion.

Broiler physiological response to low phosphorus diets at different stages of production

Phosphorus (P) inclusion in broiler diets needs to meet the physiological demands at a specific developmental stage to ensure the performance, health, and welfare of the birds and minimize nutrient losses. Toward a more efficient utilization of P in broiler husbandry, a timed nutritional conditioning strategy might enhance the endogenous mechanisms of mineral homeostasis and thus reduce dietary P supply of mineral sources. In this study, following a variable P supply in the starter phase, the effects of a dietary P depletion of broiler chickens were investigated at different developmental stages. Physiological adaptation mechanisms were elucidated based on zootechnical performance, endocrine parameters, regulation of intestinal P transport, bone characteristics, and health aspects. The results revealed a marked response to P depletion at the earliest developmental phase, after which indications of effective compensatory mechanism were detectable with advancing ages. Potential mechanisms that enable broilers to maintain mineral homeostasis primarily include endocrine control mediated by calcitriol actions, as well as intestinal P uptake and mineral mobilization from the bone. Conclusively, the precise timing, duration, and extent of a P depletion strategy in the broiler chicken might be considered for optimized nutrient utilization.

Effects of dietary calcium and phosphorus restrictions on growth performance, intestinal morphology, nutrient retention, and tibia characteristics in broiler chickens

ABSTRACT 1. This study evaluated the effects of dietary calcium (Ca)‎ and available phosphorus (aP) restrictions on growth performance, intestinal morphology, nutrient apparent total tract retention (ATTR), and tibia characteristics.2. A total of 1296, one-day-old male Ross-308 broilers were reared for 42 d. During the ‎starter phase (1-10 d), all birds were fed a nutrient-adequate diet (C). Diets fed during the grower phase (11-24 d) included: 1. C; 2. 15% of the Ca and aP in C; 3. 30% of the Ca and aP in C. At the beginning of the finisher phase (25 d), chickens fed the C diet were divided into two subgroups including C, and C+ phytase (500 FTU/kg). Restricted treatments were divided into eight subgroups as 1. C; 2. 10% of the Ca and aP in C; 3. 20% of the Ca and aP in C; 4. 30% of the Ca and aP in C; 5. C+ phytase; 6. 10% of the Ca and aP in C+ phytase; 7. 20% of the Ca and aP in C+ phytase and 8. 30% of the Ca and aP in C+ phytase. 3. On d 24 and 42, ATTR of Ca and phytate phosphorus (pP) were linearly increased by decreasing Ca and aP levels (P < 0.05). Birds receiving phytase showed higher nutrient ATTR ‎compared to those fed non-phytase supplemented diets (P < 0.05). Tibia Ca and P were linearly decreased at 24 d (P < 0.05) and tibial ash was linearly decreased (P < 0.05) at 42 d by decreasing levels of Ca and aP in finisher diets (without phytase)‎. By decreasing the levels of Ca and aP in the finisher diets (with phytase) with a 30% reduction of Ca and aP in the grower phase, tibia ash linearly decreased (P < 0.05). Using 500 FTU/kg phytase improved tibia traits compared to non-phytase supplemented treatments (P < 0.05).4. In general, decreasing dietary Ca and aP (up to 30%) during grower and finisher phases increased ATTR of minerals and decreased Ca, P and breaking strength (BS) of tibia without any negative effect on growth performance or intestinal morphology. Reduced dietary Ca and aP decreased tibial ash content, although 500 FTU/kg phytase improved ATTR of minerals and tibia attributes.

Acute High Dietary Phosphorus Following Low-Phosphorus Diet Acclimation Does Not Enhance Intestinal Fractional Phosphorus Absorption in Nephrectomized Male Rats.

Dietary phosphorus restriction and phosphorus binders are commonly prescribed for patients with chronic kidney disease (CKD). However, occurrences of non-adherence to these interventions are common. As low-phosphorus (LP) diets have been consistently experimentally shown in vitro to increase intestinal phosphorus absorption efficiency, a bout of non-adherence to diet or binders may cause an unintended consequence of enhanced intestinal phosphorus absorption. Thus, we aimed to determine the effect of a single bout of high-phosphorus (HP) intake after acclimation to a LP diet. Male Sprague Dawley rats with 5/6 nephrectomy (n=36) or sham operation (n=36) were block-randomized to 1 of 3 diets: LP (0.1% P w/w), HP (1.2%), or LP followed by acute HP (LPHP 0.1% then 1.2%). Phosphorus absorption tests were conducted using 33P radioisotope administrated by oral gavage or intravenously (iv). Although the overall two-way ANCOVA model for intestinal fractional phosphorus absorption was non-significant, exploratory comparisons showed intestinal fractional phosphorus absorption efficiency tended to be higher in rats in the LP compared with HP or LPHP groups. Rats in the HP or LPHP groups had higher plasma phosphorus compared with rats in the LP group, but the LPHP group was not different from the HP group. Gene expression of the major intestinal phosphate transporter, NaPi-2b, was lower in the jejunum of rats in the LPHP group compared with rats in the HP group but not different in the duodenum. These results demonstrate that an acute HP load after acclimation to a LP diet does not lead to enhanced intestinal fractional phosphorus absorption efficiency in 5/6 nephrectomized male rats. These data provide evidence against the notion that dietary phosphorus restriction or binder use adversely increases absorption efficiency after a single instance of dietary or binder non-adherence. However, other adverse consequences of fluctuating dietary phosphorus intake cannot be ruled out. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Effects of Dietary Phosphorus Deficiency and High Phosphorus Content on the Growth Performance, Serum Variables, and Tibia Development in Goslings

Understanding how dietary phosphorus (P) regulates the growth and skeletal development of goslings is essential for fully utilizing P in the production of geese. We aimed to study the effects of dietary P deficiency and high P content on growth performance, serum variables, tibia quality, and mRNA expression of osteogenesis-related genes in tibia to reveal how dietary P regulates bone development in goslings. Two hundred and sixteen one-day-old Jiangnan White male geese were fed corn-soybean meal diets for 14 days. The diets were set with the same calcium (Ca) level (0.80%) and three non-phytate P (NPP) levels: 0.08% (P deficiency), 0.38% (P control), and 0.80% (P high content). Each treatment consisted of six replicates with 12 goslings in each replicate. The P deficient group had a high cumulative mortality of 26.67% with lower body weight (BW), average daily feed intake (ADFI), average daily gain (ADG), serum P contents, tibia width, tibia length, tibia fresh weight at d 14 as compared with the control and high P content group (p ≤ 0.05). Dietary P deficiency caused a reduction in the goslings’ tibia strength, tibia ash content, tibia Ca content, and tibia P content during d 4–d 14 (p &lt; 0.05). The P deficiency reduced tibia mRNA expression of osteoprotegerin (OPG) and runt-related transcription factor 2 (Runx2) on d 7 (p &lt; 0.05), whereas up-regulated serum alkaline phosphatase (ALP) activity, calcitonin (CT) content, and the tibia mRNA ratio of receptor activator of NF-κB ligand (RNAKL)/OPG during d 7–d 14 (p &lt; 0.05). The serum 1,25-(OH2)D3 content, serum bone Gla-protein (BGP), and the mRNA relative expression of RNAKL and BGP in tibia were decreased in the NPP 0.08% and 0.80% groups compared with the control on d 14 (p &lt; 0.05). In conclusion, dietary P deficiency induced acute rickets in goslings as early as the fourth day. A P deficiency hindered the tibia and body growth partly due to poor skeletal calcification caused by a down-expression of osteogenesis-related genes regulated by high serum ALP activity and calcitonin contents and lower serum BGP and skeletal P contents.

Effects of Dietary Phosphorus Levels on Growth Performance, Phosphorus Utilization and Intestinal Calcium and Phosphorus Transport-Related Genes Expression of Juvenile Chinese Soft-Shelled Turtle (Pelodiscus sinensis).

A 60-day feeding trial was performed to assess the effects of dietary phosphorus levels on growth performance, body composition, phosphorus utilization, plasma physiological parameters and intestinal Ca and P transport-related gene expression of juvenile Chinese soft-shelled turtle (P. sinensis). Four diets containing available P at graded levels of 0.88%, 1.00%, 1.18% and 1.63% (termed as D0.88, D1.00, D1.18 and D1.63, respectively) were formulated and each diet was fed to turtles (5.39 ± 0.02 g) in sextuplicate. The turtles were randomly distributed to 24 tanks with 8 turtles per tank. The results indicated that final body weight, specific growth rate, feed conversion ratio and protein efficiency ratio performed best in turtles fed 1.00% available P diet. The crude lipids of the whole body exhibited a decreasing trend with the dietary available P, whereas the calcium and phosphorus of the whole body and bone phosphorus showed an opposite tendency. The apparent digestibility coefficient of phosphorus declined with the dietary available P. Turtles fed 1.00% available phosphorus had the highest phosphorus retention ratio compared with other treatments. Simultaneously they had significantly lower phosphorus loss than turtles fed D1.18 and D1.63 and had no differences in this respect from turtles fed a low-phosphorus diet. It was noteworthy that the lowest plasma calcium concentrations, and alkaline phosphatase activities in plasma and liver, were discovered in turtles fed the diet containing 1.63% available phosphorus. In addition, the high-phosphorus diet resulted in significantly down-regulated expression of intestinal phosphorus and calcium transport-related key genes. In conclusion, the available phosphorus requirement of juvenile P. sinensis was determined at 1.041% (total phosphorus was 1.80%) based on quadratic regression of weight gain rate, and excessive dietary phosphorus stunted turtle growth possibly via inhibiting intestinal calcium absorption.

Interactive effects of dietary phosphorus and microbial phytase on growth performance, intestinal morphometry, and welfare of Nile tilapia (Oreochromis niloticus) fed on low-fishmeal diets

One of the industries with the fastest growth rates in the world is aquaculture. However, as fish meal (FM), the most expensive component of aquafeeds, is increasingly replaced with plant protein, the amount of phosphorus (P) in fish diets decreases as a result of plant proteins' high phytate content, which chelates P. Inorganic P is a dietary supplement that increases fish development and feed utilization, but its high inclusion in aquafeeds causes eutrophication due to environmental contamination. Consuming dietary phytase can make more P available, which lowers the amount of inorganic P in fish diets. The present study assessed the effects of replacing inorganic P in Nile tilapia (O. niloticus) diets with a hybrid microbial phytase (HMPhyt) derived from bacteria hybrid (Buttiauxella gaviniae, Yersinia mollaretti, and Hafnia sp.) on growth and welfare. Fish (1.50 ± 0.16 g) were divided into 18,100-L tanks with 20 fish each, and they were fed one of six low FM diets that were both isonitrogenous (300 g/kg) and isocalorific (17 kJ/g). The control diet had no P or HMPhyt supplements (0P + 0HMPhyt), the second diet contained 0.2 g/kg (1000FTU/kg) HMPhyt only (0P + HMPhyt), the third diet contained 100% P (13.0 g/kg) only (100P + 0HMPhyt), and the fourth to the six diets contained 75% (9.8 g/kg) P (75P + HMPhyt), 50% (6.5 g/kg) P (50P + HMPhyt), or 25% (3.3 g/kg) P (25P + HMPhyt). Fish were fed the experimental diets three times each day for 56 days, until they appeared satisfied. In comparison to the control diet (0P + HMPhyt), the results reveal that dietary phytase and/or inorganic P significantly increased Nile tilapia growth indices and feed intake (P < 0.05) than the control group. In contrast, there were no differences in the feed conversion ratio or the percentage of fish that survived among the various fish groups (P > 0.05). In addition, fish fed on P and/or HMPhyt containing diets had significantly greater counts of red and white blood cells, packed cell volume, and hemoglobin, as well as higher intestinal villi width/height, and absorption area compared to the control group. In contrast, higher levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and malondialdehyde were found in fish fed the control diet (0P + HMPhyt), while higher levels of superoxide dismutase, catalase, lysozyme, and respiratory burst activity were found in fish fed the inorganic P and/or HMPhyt based diets As a result, dietary HMPhyt (1000 FTU/kg) can totally substitute inorganic P in Nile tilapia diets without having any negative impacts on the fish's welfare or growth.

A Review of Current Evidence on the Relationship between Phosphate Metabolism and Metabolic Syndrome.

Phosphorus, present as phosphate in biological systems, is an essential mineral for various biological activities and biochemical processes. Numerous studies have indicated that disturbed phosphate balance may contribute to the development of metabolic syndrome (MetS). However, no consistent result was found on the association between phosphorus intake and serum phosphate concentration with MetS. It is believed that both positive and negative impacts of phosphorus/phosphate co-exist in parallel during MetS condition. Reduced phosphate level contributed to the development of obesity and hyperglycaemia. Low phosphate is believed to compromise energy production, reduce exercise capacity, increase food ingestion, and impair glucose metabolism. On the other hand, the effects of phosphorus/phosphate on hypertension are rather complex depending on the source of phosphorus and subjects' health conditions. Phosphorus excess activates sympathetic nervous system, renin-angiotensin-aldosterone system, and induces hormonal changes under pathological conditions, contributing to the blood pressure-rising effects. For lipid metabolism, adequate phosphate content ensures a balanced lipid profile through regulation of fatty acid biosynthesis, oxidation, and bile acid excretion. In conclusion, phosphate metabolism serves as a potential key feature for the development and progression of MetS. Dietary phosphorus and serum phosphate level should be under close monitoring for the management of MetS.

Acidified diet is not effective in preventing hypocalcemia in dairy cows on French commercial farms

The objective of this study was to assess, in the context of typical dairy farms in western France, the preventive effects of prepartum diet acidification (AcD) and mineral intake during late gestation on the incidence of subclinical hypocalcemia (SHC) and subclinical hypophosphatemia (SHP) after calving. We conducted a longitudinal study that followed a cohort of 371 Holstein cows from 26 French dairy farms; of these, 235 cows (15 farms) were supplied with anionic salts during late gestation, and 136 cows (11 farms) were not. Blood samples were collected from 1 to 22 cows per farm (average of 14.3 cows per farm) between 24 and 48 h after calving. Total calcium and inorganic phosphorus concentrations in plasma were then quantified by inductively coupled plasma - optical emission spectrometry. The effects of AcD on the incidence of SHC and SHP were assessed using mixed linear models that evaluated the cow-level factors parity, milk yield index, and individual health events/treatments, and the farm-level factors diet calcium and magnesium content, dietary phosphorus intake, vitamin D supply, diet crude protein content, and duration of AcD, with farm as a random effect. Approximately 55% of cows were diagnosed with SHC (calcium &amp;lt; 2.0 mmol/l, n = 203) and 37% with SHP (inorganic phosphorus &amp;lt; 1.3 mmol/l, n=136). The first model confirmed earlier findings that the risk of SHC is higher with increased parity (P ≤ 0.0001) and revealed a higher risk associated with high milk yield (P = 0.0005), high phosphorus intake (40–60 g/cow per day, OR = 3.5; ≥ 60 g/cow per day, OR = 7.3; P = 0.0003) and high vitamin D supply (≥ 19950 IU/cow per day, OR = 3, P = 0.007). The second model highlighted a greater risk of SHP with increasing parity (P = 0.03) and showed trends for the preventive effects of AcD (OR = 0.4, P = 0.07) and moderate amounts of phosphorus in the diet (OR = 0.4, P = 0.10). Overall, our results do not support the effectiveness of AcD in preventing SHC or SHP under field conditions examined here, probably resulting from insufficient diet acidification.

Requirements and Metabolism for Calcium, Phosphorus and Vitamin D3 in the Growing-Furring Blue Foxes.

Simple SummaryThe nutritional needs of mink and foxes have long been clear, not specifically for blue foxes. With the development of technology, the present study aimed to study the effect of dietary calcium, phosphorus, and vitamin D3 supplementation levels on the growth performance, nutrient digestibility, and serum biochemical indicators of the growing hairy blue fox. The results showed that Ca (0.8–1.2%) and vitamin D3 (1327 IU·kg−1) doses have important effects on the growth performance and nutrient digestibility of growing blue foxes and can reduce fecal nitrogen and fecal phosphorus by improving the utilization of protein and phosphorus.A 3 × 3 factorial experiment was conducted to investigate the influence of dietary calcium, phosphorus, and vitamin D3 (VD3) supplement levels on the growth performance, nutrient digestibility, and serum biochemical indices of growing-furring blue foxes. One hundred and thirty-five 120-day-old male blue foxes were randomly allocated into nine groups. The nine treatment diets were supplemented with 0%, 0.4%, or 0.8% Ca, and 1000, 2000, or 4000 IU·kg−1 VD3. The base diet contained 0.8% Ca and 327 IU·kg−1 VD3. The dietary calcium level had a significant effect on the average daily gain (ADG) of blue foxes at 121 to 135 days of age and 136 to 150 days (p < 0.05). The ADG of blue foxes at 121 to 135 days of age was significantly decreased by VD3 level (p < 0.05). The Ca dosage decreased the nutrient digestibility (p < 0.05). The Ca dosage increased the fecal Ca and P and decreased the P digestibility (p < 0.05). Interactions were found between the Ca and VD3 levels, which affected the digestibility of Ca and P (p < 0.05). In conclusion, this research determined the suitable doses of Ca and VD3 for growing-furring blue foxes.

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.

Chemical body composition and bone growth of young pigs as affected by deficiency, adequate and excess of dietary phosphorus supply

Abstract Objective of the experiment was to study the effect of deficiency, adequate and excess dietary phosphorus supply on growth performance, retention and utilisation of phosphorus, length, mass and geometry measurements of the femur shaft, content of protein, ash, phosphorus in viscera, edible (meat and fat) and inedible (bones and skin) parts of the body in pigs ageing from 33 to 110 days. It was found that compared to animals fed according to phosphorus requirement the deficiency and excess of dietary phosphorus did not influenced o total feed intake (mean 120.6 kg) and feed conversion (mean 1.9 kg/kg gain). However phosphorus deficiency lowered total gain of the body mass (P=0.0072), diminished weight of the inedible part of the carcass (P=0.0229), decreased the content of body protein (P=0.0171), ash (P=0.0001), and phosphorus (P=0.0001). Whereas, over-supply of dietary phosphorus did not cause any change of these component. Utilisation of the total phosphorus was diminished (P=0.0001) in pigs fed diet with both excess (by 16.26%) and deficiency (by 12.28%) of the phosphorus, but excess had much lower negative impact than its’ deficiency. When available form of this element was considered over-supply still reduced (P=0.0001) its utilisation the most (by 26.58%) but deficiency made utilisation the best (7.77%). Both dietary deficiency and over-supply of the phosphorus diminished (P=0.0001) femur mass (by 25 and 11 g, respectively). Thus negative impact of phosphorus deficiency was much stronger. Moreover, phosphorus deficiency diminished (P=0.0015) bone length (by 0.5 cm), however, excess did not change this feature. Response of animals to a decrease bone mass and length due disturbances in phosphorus supply (both deficiency and excess) was the increase the vertical external diameter of the femur shaft.

Dietary Phosphorus, Its Sources, and Mortality in Adults on Haemodialysis: The DIET-HD Study.

Dietary phosphorus restrictions are usually recommended for people on haemodialysis, although its impact on patient-relevant outcomes is uncertain. We aimed to evaluate the association between total phosphorus intake and its sources with mortality in haemodialysis. Phosphorus intake was ascertained within the DIET-HD study in 8110 adults on haemodialysis. Adjusted Cox regression analyses were conducted to evaluate the association between the total and source-specific phosphorus (plant-, animal-, or processed and other sources) with mortality. During a median 3.8 years of follow-up, there were 2953 deaths, 1160 cardiovascular-related. The median phosphorus intake was 1388 mg/day. Every standard deviation (SD) (896 mg/day) increase in total phosphorus was associated with higher all-cause mortality [hazard ratio (HR), 1.16; 95% confidence intervals (CI), 1.06–1.26] and cardiovascular mortality (HR, 1.18; 95% CI, 1.03–1.36). Every SD (17%) increase in the proportion of phosphorus from plant sources was associated with lower all-cause mortality (HR, 0.95; 95% CI, 0.90–0.99). Every SD (9%) increase in the proportion of phosphorus from the processed and other sources was associated with higher all-cause mortality (HR, 1.06; 95% CI, 1.02–1.10). A higher total phosphorus intake was associated with increased all-cause and cardiovascular death. This association is driven largely by the phosphorus intake from processed food. Plant based phosphorus was associated with lower all-cause mortality.

The active core microbiota of two high-yielding laying hen breeds fed with different levels of calcium and phosphorus.

The nutrient availability and supplementation of dietary phosphorus (P) and calcium (Ca) in avian feed, especially in laying hens, plays a vital role in phytase degradation and mineral utilization during the laying phase. The required concentration of P and Ca peaks during the laying phase, and the direct interaction between Ca and P concentration shrinks the availability of both supplements in the feed. Our goal was to characterize the active microbiota of the entire gastrointestinal tract (GIT) (crop, gizzard, duodenum, ileum, caeca), including digesta- and mucosa-associated communities of two contrasting high-yielding breeds of laying hens (Lohmann Brown Classic, LB; Lohmann LSL-Classic, LSL) under different P and Ca supplementation levels. Statistical significances were observed for breed, GIT section, Ca, and the interaction of GIT section x breed, P x Ca, Ca x breed and P x Ca x breed (p < 0.05). A core microbiota of five species was detected in more than 97% of all samples. They were represented by an uncl. Lactobacillus (average relative abundance (av. abu.) 12.1%), Lactobacillus helveticus (av. abu. 10.8%), Megamonas funiformis (av. abu. 6.8%), Ligilactobacillus salivarius (av. abu. 4.5%), and an uncl. Fusicatenibacter (av. abu. 1.1%). Our findings indicated that Ca and P supplementation levels 20% below the recommendation have a minor effect on the microbiota compared to the strong impact of the bird’s genetic background. Moreover, a core active microbiota across the GIT of two high-yielding laying hen breeds was revealed for the first time.

273 Awardee Talk: A Perspective on Calcium and Phosphorus Nutrition: Where we are and the Opportunities Ahead

Abstract Quantifying dietary calcium (Ca) and phosphorus (P) that can be used in the body of the animal is important for formulating nutritionally adequate diet and for efficient production of animal products. Historically, utilizable Ca and P in feedstuffs have been determined using the slope-ratio bioassays. The relative available Ca or P obtained from the assay is highly dependent on, among others, the available Ca or P in the reference source and the response criterion; and the measure is not usually additive in mixed feeds. The most common response criteria are bone ash and mineral concentration, or breaking strength, which tend to be labor-intensive and expensive, and very importantly do not provide estimates of mineral quantities voided by animals. The use of digestible in place of relative available overcomes some of the issues listed. For the formulation of diets that more accurately match requirement with dietary supply as well as proper quantification of excretion of P for environmental considerations, the use of relative available phosphorus as a currency is nebulous. Because colonic secretion or absorption of Ca has been shown in previous studies, it was important to, first, answer the question on whether there is a difference between Ca digestibility determined by the ileal cannulation technique or the total tract digestibility method. Unlike in poultry where urine P contributes to excreta in total tract, there is no difference between ileal and total tract digestibility of P in swine. The prominence of literature on utilization of Ca and P has provided more clarity in the understanding of the intricate interactions among Ca, P, and phytase. Issues of variation require more investigation into method standardization as well as additivity of digestible Ca and P values in mixed diet.

Review of waste phosphorus from aquaculture: Source, removal and recovery

AbstractThe contribution of phosphorus to water body eutrophication is a global environmental problem, and rapid increases in aquaculture are considered a significant source of phosphorus discharged into the environment. The current review focuses on the source of aquaculture waste phosphorus and measures to decrease phosphorus release into the environment. Because diets are a significant source of phosphorus in fed aquaculture systems, improving the utilization efficiency of dietary phosphorus can reduce the amount of waste phosphorus at the source. A wide range of removal and recovery technologies has been identified, including adsorption, crystallization, enhanced biological phosphorus removal (EBPR), denitrifying phosphorus removal, heterotrophic nitrification aerobic denitrification (HAND) and photosynthetic organism removal. Recovery technologies were also reviewed, particularly sludge phosphorus from recirculating aquaculture systems. A new method using bacteria to immobilize waste nitrogen and phosphorus into bioflocs has been proposed as a better solution. However, most of these technologies have only been implemented at the lab scale to pilot scale. Further studies are necessary to determine the working conditions and removal capacities of related technologies on a commercial scale. Moreover, phosphorus removal methods must be selected based on a consideration of recyclability.

17. Mechanistic model of the fate of dietary phosphorus and calcium in growing broilers

17. Mechanistic model of the fate of dietary phosphorus and calcium in growing broilers

Associations of Dietary Macroelements with Knee Joint Structures, Symptoms, Quality of Life, and Comorbid Conditions in People with Symptomatic Knee Osteoarthritis.

Background: Osteoarthritis (OA), the most common joint disease in the elderly, has no cure. Macroelements are vital in human health and their relationships with OA are not clear. Clarifying the relationships between macroelements and OA may assist knee OA management. Methods: This study was a post-hoc analysis using data from a two-year randomized controlled trial among 392 participants with knee OA. Dietary macroelements, including calcium, magnesium, potassium, and phosphorus were computed-based on a semi-quantitative food frequency questionnaire at baseline. Knee joint structures (including cartilage volume, cartilage defect, bone marrow lesions, and effusion-synovitis volume), OA symptoms, quality of life, and OA comorbid conditions (including lower limb muscle strength and depressive symptoms) were assessed at baseline and month 24. Western Ontario and McMaster Universities (WOMAC) Index and depressive symptoms were assessed at baseline and months 3, 6, 12, and 24. Quality of life and lower limb muscle strength were assessed at baseline and months 6, 12, and 24. All analyses were conducted using mixed-effects models. Results: Higher dietary magnesium and potassium were associated with fewer OA symptoms, higher quality of life, greater lower limb muscle strength, and fewer depressive symptoms, but not with knee joint structures. Higher dietary calcium and phosphorus was not associated with any of the OA-related outcomes, except that dietary phosphorus was associated with greater lower limb muscle strength. Conclusions: In the longitudinal analyses, higher dietary magnesium and potassium intake are associated with fewer OA symptoms, higher quality of life, and milder comorbid conditions in patients with knee OA, suggesting dietary magnesium and potassium may have beneficial effects on OA and could be used for knee OA management.

Effects of dietary phosphorus concentration and phosphate salt form on renal tubule function in unilateral nephrectomized rats.

Background: Excessive consumption of phosphorus (P) impairs renal tubule function; however, the effects of different dietary phosphate salts on chronic kidney disease (CKD) are unclear. Aim: To examine the effects of potassium dihydrogen phosphate (KH2PO4) and potassium tripolyphosphate (K5P3O10) and P concentration on renal function in a rat model of early CKD. Methods: Male sham-operated Sprague-Dawley rats were fed a diet containing KH2PO4 with a normal P level. Kidney injury was induced by unilateral nephrectomy (UNx), and the rats were divided into four groups fed dietary KH2PO4 or K5P3O10 with a normal (UNx-NKH, UNx-NKP) or high (UNx-HKH, UNx-HKP) P concentration, respectively, for 21 days. Results: UNx-NKH rats showed significantly lower creatinine clearance (CCr) and higher albumin (ALB) compared with those of sham rats, confirming UNx-induced kidney injury. The urinary levels of liver-type fatty acid-binding protein (L-FABP) and ALB were significantly higher in UNx-HKP rats than in UNx-HKH rats. However, other markers of renal tubule function, such as CCr, serum creatinine (CRE), calcium (Ca), and hormones, only differed among groups according to the P concentration and not the dietary phosphate salt form. Histological examination showed higher incidence and severity of tubulointerstitial lesions, tubule regeneration, tubule dilation, and calcification in the high-phosphorus than in the normal-phosphorus UNx groups. These changes were more severe in the UNx-HKP group compared with the UNx-HKH group. Conclusion: This study highlights the importance of controlling dietary P intake in terms of both concentration and source to prevent the progression of CKD.

Phosphate Frustration: Treatment Options to Complement Current Therapies.

Hyperphosphatemia eventually develops in almost all patients with advanced chronic kidney disease and is associated with negative clinical outcomes. Thus, guidelines recommend targeting treatment to normal phosphate levels in patients with chronic kidney disease. Despite low phosphorus diets, clearance by dialysis, and phosphate binder use, many patients with chronic kidney disease on dialysis are unable to consistently achieve and maintain serum phosphate concentrations <5.5 mg/dL. A chart audit of patients on dialysis receiving phosphate binders showed that 74 to 86% were unable to consistently achieve serum phosphate ≤5.5 mg/dL over 6 months. Furthermore, although there is evidence that serum phosphate concentrations <4.5 mg/dL are associated with improved survival and cardiovascular outcomes, real-world phosphate control data suggest achieving and maintaining this goal for most patients would be extremely challenging, if not near impossible, using current therapies. As phosphate binders can only remove approximately 300 mg of the 2,500 mg or more daily dietary phosphate intake, therapeutic innovations are necessary to improve phosphate management. We present treatment options to complement current therapies including tenapanor, a novel sodium/hydrogen exchanger isoform 3 inhibitor that blocks the dominant paracellular phosphate absorption pathway and has been shown to reduce phosphate levels in several clinical trials.