High-phytate Diet Research Articles

Microalgae polyphosphate nanoparticles deliver bioavailable calcium against phytate antagonism: Ex vivo and in vivo studies

Biogenic nanoparticles are promising carriers to deliver essential minerals. Here, calcium-enriched polyphosphate nanoparticles (CaPNPs) with a Ca/P molar ratio > 0.5 were produced by Synechococcus sp. PCC 7002 in the growth medium containing 1.08 g/L CaCl2, and had nearly spherical morphologies with a wide size distribution of 5–75 nm and strongly anionic surface properties with an average ζ-potential of –39 mV, according to dynamic light-scattering analysis, transmission and scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The ex-vivo ligated mouse ileal loop assays found that calcium in CaPNPs was readily available to intestinal absorption via both ion channel-mediated and endocytic pathways, specifically invoking macropinocytic internalization, lysosomal degradation, and transcytosis. Rat oral pharmacokinetics revealed that CaPNPs had a calcium bioavailability approximately 100 % relative to that of CaCl2 and more than 1.6 times of that of CaCO3. CaPNPs corrected the retinoic acid-induced increase in serum calcium, phosphorus, and bone-specific alkaline phosphatase, and decrease in serum osteocalcin, bone mineral content/density, and femoral geometric parameters with an efficacy equivalent to CaCl2 and markedly greater than CaCO3. In contrast to CaCl2, CaPNPs possessed desirable resistance against phytate’s antagonistic action on calcium absorption in these ex vivo and in vivo studies. Overall, CaPNPs are attractive as a candidate agent for calcium supplementation, especially to populations on high-phytate diets.

Evaluation of exogenous phytase in high-phytate diets for broiler chickens and pigs

There is a gap in the understanding of the relationship between dietary phytate levels and the relative efficacy of phytase to improve amino acid (AA) digestibility in pigs and chickens. Two experiments were conducted to investigate the effect of exogenous phytase on standardized ileal digestibility (SID) of AA and the apparent ileal digestibility (AID) of P in both standard- (SP) and high-phytate (HP) diets for broilers and swine. There were either 40 cages of Cobb 500 male broilers or 10 crossbred barrows (35 kg) fitted with ileal T-cannulas. Both studies were allotted to five dietary treatments (8 replicates). Treatments consisted of four corn-soybean meal-based diets arranged in a 2 × 2 factorial of standard or high phytate and exogenous phytase at 0 or 1 000 phytase units (FYT)/kg; and one N-free diet. Birds were fed a common starter diet from d 0 to 20 and fed experimental diets from d 20 to 25. Birds were euthanized on d 25 via CO2 asphyxiation, and digesta were collected from the terminal ileum. Pigs were fed for a total of four 7-d periods, where digesta were collected on d 6 and 7 of each period. Diet and digesta samples were analyzed for DM, N, Ti, AA, and P to determine AA and P digestibility. The SID of AA was determined by correcting the AID of AA for the basal endogenous losses estimated using the N-free diet. Main effects of the diet type (standard or HP) and phytase (0 or 1 000 FYT/kg), and the interaction of diet type and phytase were evaluated. For both experiments, the HP diets produced lower SID of AA compared to the SP (P < 0.001). For broilers, there was a phytase effect (P < 0.001) for the SID of all AAs evaluated regardless of the diet type. For pigs, phytase improved (P < 0.05) the SID of Met, Lys, Cys, Glu and Ser and tended to improve (P < 0.10) Arg, Leu, Thr, and Tyr. There were no significant interactions for either experiment. For both experiments, AID of P was lower for the HP diets (P < 0.01), and phytase produced greater AID of P for both diet types (P < 0.01). These data indicate that phytase greatly improves the digestibility of P for broilers and pigs and has the ability to significantly increase the digestibility of amino acids for these animals, regardless of the dietary phytate P.

Efficacy of a novel phytase in response to low and high phytate diets using a short-term digestibility model in broiler chickens at two ages

A total of 2000 male broilers were used to evaluate the efficacy of a novel phytase in terms of phytate hydrolysis and apparent ileal digestibility coefficient (AIDC) of phosphorus (P) and calcium (Ca), in response to low and high phytate diets, using a short-term digestibility model in broiler chickens at two ages. The experimental diets were in a 2 × 5 factorial arrangement with 2 dietary phytate concentrations (low or high) and 5 doses of a novel phytase supplemented at 0, 500, 1000, 2000 FYT/kg or extradose (3000 or 4000 FYT/kg for low or high phytate diet, respectively). The extradosing of phytase was intended for nearly complete phytate hydrolysis when considering the phytate levels in the diet. Ten treatments with 10 replicate cages each were fed to birds for 36-hours at 9–11 or 19–21 days of age (12 or 8 birds per replicate). From day 9–11, a lower dose of phytase was able to improve feed conversion ratio (FCR) for birds fed high phytate diet, resulting in a phytase × phytate interaction (P < 0.05). Phytase supplementation (P < 0.05) or high phytate diet (P < 0.05) improved FCR at day 19–21, and increased body weight gain (BWG) at both ages. From day 9–11, a higher dose of phytase was required in birds fed high phytate diet to increase ileal phytate P degradation and AIDC of P comparable to the values of birds fed low phytate diet (phytase × phytate interaction, P < 0.05); whereas this interaction was not detected for birds at day 19–21, the two aforementioned measurements were increased with phytase supplementation (P < 0.05) or decreased with high phytate diet (P < 0.05). Interestingly, a phytase × phytate interaction (P < 0.05) was observed for AIDC of Ca, digestible Ca and P at both ages: a lower dose of phytase was needed to maximize AIDC of Ca and digestible Ca in high phytate diet when compared to low phytate diet; while a higher dose of phytase provided digestible P to a greater extent in high phytate diet compared with low phytate diet. In conclusion, phytase effectively hydrolyzed phytate P and increased digestible P and Ca. The impact of dietary phytate on phytase efficacy varied in terms of Ca or P response, and the extent of impact was different in younger compared with older birds.

Effects of supplemental myo-inositol on growth performance and apparent total tract digestibility of weanling piglets fed reduced protein high-phytate diets and intestinal epithelial cell proliferation and function.

Myo-inositol is a breakdown product of phytate produced in the gut through the action of phytase. Although the effect of phytase-released phosphorus (P) on growth performance of animals has been well characterized, there is still little understanding of the effect of myo-inositol. The first objective of this study was to determine the effects of added myo-inositol to a phytate-rich low-protein diet on growth performance and apparent total tract digestibility (ATTD) in growing piglets. The second objective was to determine whether myo-inositol could directly affect intestinal epithelial cell proliferation and function for which we used intestinal porcine epithelial cells (IPEC-J2). A total of 128 weanling piglets were allotted to four dietary treatments consisting of eight replicates per treatment and four piglets per replicate in a randomized complete block design for 4 wk. The four experimental diets comprised the positive control [PC; 20% crude protein (CP)], negative control (NC; 17% CP), negative control plus 2.0g/kg myo-inositol (NC+INO; 17% CP), and negative control plus 3000FTU/kg phytase (NC+PHY; 17% CP). Average daily feed intake (ADFI), average daily gain (ADG), and gain-feed ratio (G: F) were recorded. Phytase supplementation in the protein-deficient NC diet increased the G:F ratio (P < 0.05) without myo-inositol effects on growth performance. Phosphorus digestibility in the phytase-supplemented group increased compared to the PC, NC, and NC+INO groups, whereas plasma myo-inositol concentration was significantly higher (P < 0.05) in the NC+INO group. Due to the lack of myo-inositol effect on growth performance, an additional in vitro study was conducted to determine the direct effect of myo-inositol on the intestinal epithelium that might not be reflected in growth performance. Myo-inositol increased the mRNA abundance of selected nutrient transporters in a concentration-dependent manner (P < 0.05). Myo-inositol also enhanced barrier integrity in the IPEC-J2 monolayer by increasing the transepithelial electrical resistance (TEER) with reduced paracellular permeability of FITC-dextran (P < 0.05). In conclusion, despite the lack of myo-inositol effect on animal performance, the in vitro data indicate that myo-inositol may directly regulate gut barrier integrity. Addition of myo-inositol to pig diets at levels that enhance intestinal epithelial cell function may result in effects on growth performance and gut health of pigs.

High-Phytate Diets Increase Amyloid β Deposition and Apoptotic Neuronal Cell Death in a Rat Model.

Amyloid-β (Aβ) accumulation in the hippocampus is an essential event in the pathogenesis of Alzheimer’s disease. Insoluble Aβ is formed through the sequential proteolytic hydrolysis of the Aβ precursor protein, which is cleaved by proteolytic secretases. However, the pathophysiological mechanisms of Aβ accumulation remain elusive. Here, we report that rats fed high-phytate diets showed Aβ accumulation and increased apoptotic neuronal cell death in the hippocampus through the activation of the amyloidogenic pathway in the hippocampus. Immunoblotting and immunohistochemical analyses confirmed that the overexpression of BACE1 β-secretase, a critical enzyme for Aβ generation, exacerbated the hippocampal Aβ accumulation in rats fed high-phytate diets. Moreover, we identified that parathyroid hormone, a physiological hormone responding to the phytate-mediated dysregulation of calcium and phosphate homeostasis, plays an essential role in the transcriptional activation of the Aβ precursor protein and BACE1 through the vitamin D receptor and retinoid X receptor axis. Thus, our findings suggest that phytate-mediated dysregulation of calcium and phosphate is a substantial risk factor for elevated Aβ accumulation and apoptotic neuronal cell death in rats.

Effects of Zinc Source and Enzyme Addition on the Fecal Microbiota of Dogs.

Supplemental zinc from organic sources has been suggested to be more bioavailable than inorganic ones for dog foods. However, the bioavailability of zinc might be affected by dietary constituents such as phytates. The present study aimed to evaluate the effects of two zinc sources (zinc sulfate and zinc proteinate) and the addition of a multi-enzymatic complex from the solid-state fermentation of Aspergillus niger on end-products of fecal fermentation and fecal microbiota of adult Beagles fed a high-phytate diet. The experimental design consisted of three 4 × 4 Latin Squares with a 2 × 2 factorial arrangement of treatments (n = 12 Beagles), with four periods and four diets: zinc sulfate without (IZ) or with (IZ +) enzyme addition, and zinc proteinate without (OZ) or with (OZ +) enzyme addition. Enzyme addition significantly affected Faith’s phylogenetic diversity index, whereas zinc source did not affect either beta or alpha diversity measures. Linear discriminant analysis effect size detected nine taxa as markers for organic zinc, 18 for inorganic source, and none for enzyme addition. However, with the use of a negative binomial generalized linear model, further effects were observed. Organic zinc was associated with a significantly higher abundance of Firmicutes and lower Proteobacteria and Bacteroidetes, although at a genus level, the response varied. The DNA abundance of Clostridium cluster I, Clostridium cluster XIV, Campylobacter spp., Ruminococcaceae, Turicibacter, and Blautia was significantly higher in dogs fed IZ and IZ + diets. Higher abundance of genus Lactobacillus was observed in dogs fed enzyme-supplemented diets. End-products of fecal fermentation were not affected by zinc source or enzymes. An increase in some taxa of the phyla Actinobacteria and Firmicutes was observed in feces of dogs fed organic zinc with enzyme addition but not with inorganic zinc. This study fills a gap in knowledge regarding the effect of zinc source and enzyme addition on the fecal microbiota of dogs. An association of zinc bioavailability and bacteria abundance is suggested, but the implications for the host (dog) are not clear. Further studies are required to unveil the effects of the interaction between zinc sources and enzyme addition on the fecal microbial community.

Comparative digestibility and retention of calcium and phosphorus in normal- and high-phytate diets fed to gestating sows and growing pigs

The objective of this research was to test the hypothesis that calculated values for standardized total tract digestibility (STTD) and retention of Ca and P are not different between gestating sows and growing pigs. A total of 32 gestating sows (day of gestation = 40) and 32 castrates (body weight = 19.8 kg) were placed in metabolism crates. Two diets were formulated to contain 9.8 or 29.4 g/kg phytate. Diets were formulated based on corn, soybean meal, Ca carbonate, and dicalcium phosphate and the high-phytate diet also contained 400 g/kg full-fat rice bran. A Ca-free diet and a P-free diet were used to determine basal endogenous losses of Ca and P. Feces and urine were collected for 4 days after 4 days of adaptation. Results indicated that basal endogenous losses of Ca and P from gestating sows were greater (P < 0.05) than from growing pigs. The digestibility of dry matter was not affected by the physiological state of the animals, but was greater (P < 0.001) in the normal-phytate diet than in the high-phytate diet. Phytate level did not affect the STTD of Ca or Ca retention by gestating sows, but the STTD of Ca and Ca retention were greater if growing pigs were fed the normal-phytate diet than if they were fed the high-phytate diet (physiological state × phytate level interaction; P < 0.001). The STTD of P was greater for the normal-phytate diet than for the high-phytate diet, but the difference was greater for growing pigs than for gestating sows (physiological state × phytate level interaction; P = 0.002). Phosphorus retention by growing pigs fed the normal-phytate diet was greater than if they were fed the high-phytate diet, but P retention by gestating sows was not affected by phytate level (physiological state × phytate level interaction; P < 0.001). Regardless of phytate level, gestating sows had reduced (P < 0.001) STTD of Ca and P and reduced retention of Ca and P compared with growing pigs. In conclusion, gestating sows have reduced digestibility and retention of Ca and P, but increased basal endogenous losses of Ca and P, compared with growing pigs. Response to dietary phytate is different for STTD and retention of Ca and P between gestating sows and growing pigs. It may, therefore, not always be accurate to formulate diets for gestating sows using digestibility values for Ca and P that were obtained in growing pigs.

The response of zinc transporter gene expression of selected tissues in a pig model of subclinical zinc deficiency

This study compared the relative mRNA expression of all mammal zinc (Zn) transporter genes in selected tissues of weaned piglets challenged with short-term subclinical Zn deficiency (SZD). The dietary model involved restrictive feeding (450 g/animal*day−1) of a high-phytate diet (9 g/kg) supplemented with varying amounts of zinc from ZnSO4*7H2O ranging from deficient to sufficient supply levels (total diet Zn: 28.1, 33.6, 38.8, 42.7, 47.5, 58.2, 67.8, 88.0 mg Zn/kg). Total RNA preparations comprised jejunal and colonic mucosa as well as hepatic and nephric tissue. Statistical modelling involved broken-line regression (P≤.05). ZIP10 and ZIP12 mRNAs were not detected in any tissue and ZnT3 mRNA was only identified in the kidney. All other genes were expressed in all tissues but only a few gene expression patterns allowed a significant (P<.0001) fitting of broken-line regression models, indicating homeostatic regulation under the present experimental conditions. Interestingly, these genes could be subcategorized by showing significant turnarounds in their response patterns, either at ~40 or ~60 mg Zn/kg diet (P<.0001). In conclusion, the present study showed clear differences in Zn transporter gene expression in response to SZD compared to the present literature on clinical models. We recognized that certain Zn transporter genes were regulated under the present experimental conditions by two distinct homeostatic networks. For the best of our knowledge, this represents the first comprehensive screening of Zn transporter gene expression in a highly translational model to human physiology.

Effect of a Multi-Carbohydrase and Phytase Complex on the Ileal and Total Tract Digestibility of Nutrients in Cannulated Growing Pigs.

Simple SummaryIt is well accepted that monogastric livestock lack phytase in their gastrointestinal tracts. Phytate (myo-inositol hexaphosphate, IP6) is the principal storage form of phosphorus (P) in many plant feeds, which can barely be used as a P source for animals. In addition, IP6 reduces the utilization of the proteins, amino acids, and minerals. Most of the IP6 is in the indigestible fibrous part of cereal grains, which also contain non-starch polysaccharides (NSP) that might also be beneficial for the availability of P, proteins, and amino acid. In this study, the multi-carbohydrase and phytase complex (MCPC) was tested to evaluate the effects on the ileal and total tract nutrients digestibility in growing pigs fed with low and high levels of phytate. The dietary supplementation of the MCPC improved the apparent ileal digestibility (AID) of P and calcium (Ca), along with the apparent total tract digestibility (ATTD) of crude fat, P, and Ca both in low and high phytate diet. Moreover, only a trend in enhanced protein digestibility was observed in the low phytate diet. In summary, the MCPC can be used in the diet of growing pigs which mainly promote the ADI and ATTD of P and Ca, which improve the efficiency of pig production.The current study evaluated the influence of a multi-carbohydrase and phytase complex (MCPC) on the ileal and total tract digestibility of nutrients in growing pigs. A total of eight barrows (initial BW = 30.7 ± 1.1 kg) were surgically fitted with a T-cannula at the distal ileum and randomly allotted to four groups. The experiment was conducted according to a 4 × 4 Latin square design, each period lasting 10 days. Pigs were fed four experimental diets, which consisted of two basal diets (BD1, low phytate; BD2, high phytate) with or without MCPC containing at least 1800 U xylanase, 6600 U α-arabinofuranosidase, 1244 U β-glucanase, and 1000 U phytase per/kg corn–soybean meal with 15% corn distillers based diet. The high phytate diet reduced (p < 0.05) the apparent ileal digestibility (AID) of crude protein by 1.4% and the apparent total tract digestibility (ATTD) of organic matter, crude protein, and gross energy by 1.7, 2.3, and 1.9%, respectively, and tended to decrease (p = 0.10) the ATTD of Ca by 17.3%, relative to the low phytate diet. The dietary supplementation of the MCPC increased (p < 0.05) the AID of phosphorus (P) and calcium (Ca) by 34.2% and 31.1% for BD1 and 26.7% and 41.3% for BD2, respectively, and increased (p < 0.05) ATTD of crude fat, P, and Ca by 1.4%, 45.6%, and 9.6% for BD1 and 3.1%, 66.0%, and 52.7% for BD2, respectively. The MCPC supplementation did not significantly increase the AID and (or) ATTD of crude protein, organic matter, and starch. In conclusion, the dietary supplementation of the MCPC could improve the AID of P and Ca and the ATTD of crude fat, P, and Ca.

Effect of Zinc Source and Exogenous Enzymes Supplementation on Zinc Status in Dogs Fed High Phytate Diets.

Simple SummaryPet food is a sector in expansion, demanding novel solutions for old issues. The mineral supplementation of animal feed has been a target of research for livestock animals, but less attention has been devoted to companion animals. The present study offers both nutritionists and pet food manufacturers knowledge concerning organic and inorganic sources of zinc for dog food supplementation. Zinc proteinate and zinc sulfate were added to a high phytate dry food for healthy dogs at maintenance. Moreover, the role of exogenous enzymes to overcome the undesirable effects of phytates was also studied, with the inclusion of a solid-state fermentation product from Aspergillus niger. Data suggest that organic zinc is promising for dog food supplementation. Yet, the use of exogenous enzymes seems to require refinement to fit the needs and physiological conditions of dogs and thus add value to mineral availability and nutrient digestibility. Zinc is an essential element, a cofactor of many enzymes, and performs catalytic, structural and regulatory functions. Once in the gastrointestinal tract, zinc can interact with food constituents. Phytic acid, the major phosphorus storage in plants, limits zinc availability from animal feeds due to the formation of insoluble complexes with phytates. This study tested the effect of supplemental zinc source (zinc sulfate and a chelate zinc proteinate) and the addition of exogenous enzymes from a solid-state fermentation product of Aspergillus niger to a high phytate diet. The study was designed according to three Latin Squares 4 × 4 with a 2 × 2 factorial arrangement of treatments, with four periods, four diets, and 12 young adult Beagles. Periods lasted 5 weeks each. Diets were supplemented with 75 mg/kg of zinc sulfate (IZ) or zinc proteinate (OZ), and without or with 200 mg/kg of exogenous enzymes (IZ+, OZ+). Results showed that zinc proteinate increased the bioavailability of phosphorus, yet the zinc biomarkers remained unaffected by the zinc source, with the exception of lymphocyte subsets that benefit from zinc proteinate. The use of exogenous enzymes did not affect zinc availability nor nutrient and energy digestibility.

Influence of graded concentrations of phytase in high-phytate diets on growth performance, apparent ileal amino acid digestibility, and phytate concentration in broilers from hatch to 28 D post-hatch.

An experiment was conducted to evaluate graded doses of phytase in high-phytate diets. Ross 308, male broilers (n = 600) were assigned to one of 4 diets, with 10 replicate pens/diet and 15 birds/replicate pen. Diets were a nutrient adequate positive control (PC), a negative control (NC) diet with a reduction of Ca by 0.22%, available P by 0.20%, energy by 120kcal/kg, and amino acids by 1 to 5% compared with the PC. The NC diet was supplemented with 0, 2,000, or 4,000 phytase units (FTU)/kg. Phytase increased (linear, P < 0.05) weight gain from hatch to day 18. Birds fed the NC + 4000 FTU/kg ate and gained more (P < 0.05) than birds fed the PC. The apparent ileal digestibility (AID) of all nutrients and amino acids were reduced (P < 0.05) in birds fed the NC compared with birds fed the PC. Phytase increased (linear, P < 0.10) AID of most nutrients. Digestibility was lower (P < 0.10) in birds fed the NC + 4000 FTU/kg compared with birds fed the PC. Using daily intake and AID to determine digestible nutrient intake resulted in no differences between birds fed the PC or NC + 4000 FTU/kg diets. Digestible intake of methionine or glutamate was better correlated with BW gain (P < 0.0001) than AID (P > 0.10). Phytase reduced (linear, P < 0.01) phytate concentration and increased inositol (linear, P < 0.01), phytate hydrolysis (linear, P < 0.05), and jejunal expression (linear, P < 0.05) of SNAT-1 and LAT-4 transporters. Supplementation of increasing doses of phytase in high-phytate, low-nutrient dense diets improved gain and digestibility through nearly complete phytate destruction. Digestible nutrient intake may be a better indication of broiler gain than AID alone.

157 Comparative Digestibility and Retention of Calcium and Phosphorus By Gestating Sows and Growing Pigs Fed Low- and High-Phytate Diets without or with Microbial Phytase.

157 Comparative Digestibility and Retention of Calcium and Phosphorus By Gestating Sows and Growing Pigs Fed Low- and High-Phytate Diets without or with Microbial Phytase.

Regular Consumption of a High-Phytate Diet Reduces the Inhibitory Effect of Phytate on Nonheme-Iron Absorption in Women with Suboptimal Iron Stores ,

Background: High phytate (HP) consumption is a concern in developing countries because of the high prevalence of iron deficiency in these countries.Objective: We investigated whether habitual consumption of an HP diet reduces the inhibitory effect of phytate on nonheme-iron absorption.Methods: Thirty-two nonanemic females, 18–35 y of age, with normal body mass index but with suboptimal iron stores (serum ferritin, ≤30 μg/L), were matched for serum ferritin concentration and randomly assigned to HP and low-phytate (LP) groups, in a parallel design study. Each subject consumed HP or LP foods with at least 2 of their daily meals for 8 wk, resulting in a change in phytate intake (from 718 to 1190 mg/d in the HP group and 623 to 385 mg/d in the LP group). The serum iron response over 4 h after a test meal containing 350 mg of phytate was measured at baseline and postintervention. Ferritin, transferrin receptor, and hepcidin concentrations were measured at baseline and 8 wk.Results: Twenty-eight subjects completed the study (n = 14 per group). The serum iron response to the test meal increased in the HP group at postintervention, resulting in a 41% increase in the area under the curve (AUC; P < 0.0001). However, no effect was observed in the LP group (21% decrease in AUC; P = 0.76). The postintervention serum iron response was lower (P < 0.0001) in the LP group than in the HP group after controlling for the baseline serum iron response and hepcidin concentration, reflecting in a 64% lower AUC.Conclusions: We found that habitual consumption of an HP diet can reduce the negative effect of phytate on nonheme-iron absorption among young women with suboptimal iron stores. Future studies are needed to explore possible mechanisms. This trial was registered at clinicaltrials.gov as NCT02370940.

Influence of phytate level on broiler performance and the efficacy of 2 microbial phytases from 0 to 21 days of age

Phytate is an antinutrient in animal feeds, reducing the availability and increasing the excretion of nutrients. Phytases are widely used to mitigate the negative influences of phytate. This trial was designed to compare the efficacy of 2 Escherichia coli-derived phytases on broiler performance and bone ash as influenced by dietary phytate level. A total of 1,024 Arbor Acres male broilers were used with 8 replicate pens of 16 birds/pen. Experimental diets were based on low available phosphorus (avP; 1.8 g/kg) with low (6.40 g/kg) or high (10.65 g/kg) phytate. The low-avP diets were then supplemented with mono-dicalcium phosphate to increase the avP level to 4.5 g/kg, 500 phytase units/kg of phytase A, or 500 phytase units/kg of phytase B to create 8 experimental diets. Feed intake, BW gain, FCR, and livability were influenced by a P source × phytase interaction. Feed intake, BW gain, and livability were reduced and FCR was higher in broilers fed low-avP diets, particularly in the presence of high phytate. Phytase A or phytase B improved feed intake, BW gain, and FCR, particularly in the high-phytate diet. However, broilers fed phytase A ate more and were heavier than broilers fed phytase B. Tibia ash was lowest in broilers fed the low-avP diet and highest in broilers fed the diet supplemented with mono-dicalcium phosphate. Phytase increased tibia ash, and broilers fed phytase A had an increase in tibia ash compared with broilers fed phytase B. In conclusion, high dietary phytate reduced broiler performance. Phytase A and phytase B improved bone ash and growth performance, especially in the high-phytate diets. However, phytase A was more efficacious than phytase B, regardless of the level of phytate.

Adaptation of iron bioavailability with high phytate diet consumption (122.6)

Phytate is one of the inhibitors of nonheme iron absorption which is of particular concern in developing countries. In this study, we investigated whether individuals adapt to the inhibitory effect of phytate on iron bioavailability. Female subjects with Ferritin &lt; 30µg/L (n=28) were randomized into two groups of 14 after matching for ferritin. Each group consumed either high or low phytate foods that were provided for 8 weeks. Iron bioavailability from a high phytate test meal was measured using area under the curve (AUC) for serum iron at baseline and after the intervention. During the 8 week period, phytate intake increased significantly (p&lt;0.01) in the high phytate (HP) group and decreased significantly (p&lt;0.001) in the low phytate (LP) group. No significant changes were observed in ferritin and transferrin receptor concentrations in both groups. AUC increased significantly (p&lt;0.05) in the HP group (640 to 905 µmol/L) but the decrease (337 to 267 µmol/L) in the LP group was not significant. We found a strong positive correlation between phytate intake and AUC (r=0.68, p&lt;0.0001) and a negative correlation between hepcidin and AUC at post intervention (r= ‐0.48; p=0.011). Our data suggests that iron bioavailability from high phytate meal may improve in individuals who consume a habitual high phytate diet. Further studies on how long term dietary changes affect the regulation of iron absorption are needed.Grant Funding Source: IFPRI/HarvestPlus

Relative bioavailabilities of organic zinc sources with different chelation strengths for broilers fed diets with low or high phytate content

A six-day experiment was conducted to estimate the relative bioavailability values (RBV) of zinc (Zn) in three organic sources (oZn) with different chelation strengths compared to inorganic ZnSO4 (iZn) for broilers fed a low or high phytate diet. A total of 1080, one-d-old male broiler chicks were randomly assigned to one of 18 dietary treatments (six replicates cages of ten chicks per cage) in a completely randomized design involving a 2×2×4 factorial arrangement with two levels of added phytate (0 or 10g phytate as sodium phytate/kg), two levels of added Zn (30 or 60mg/kg) and four Zn sources (iZn and three oZn sources) plus one low and one high phytate control treatments without Zn addition. The three oZn sources consisted of (1) Zn amino acid with weak chelation strength (ZnAA-L, formation quotient Qf=6.6, containing 119g Zn/kg), (2) Zn proteinate with moderate chelation strength (ZnPRO-M, Qf=30.7, containing 133g Zn/kg) or (3) Zn proteinate with strong chelation strength (ZnPRO-H, Qf=944.0, containing 186g Zn/kg). Chicks were harvested at 6 days of age and pancreas metallothionein (MT) mRNA expression was used to estimate Zn RBV. Pancreas MT mRNA expression increased (P<0.01) as dietary Zn level increased. Chicks fed high phytate diets had lower (P<0.05) MT mRNA expression than chicks fed low phytate diets. Based on multiple linear regression slope ratios with ZnSO4 set at 1.00, the RBV of ZnAA-L, ZnPRO-M and ZnPRO-H were 1.01, 1.28 and 0.70, respectively, for low phytate diets, and 1.05, 1.39 and 0.92, respectively, for high phytate diets. The slope for the oZn source with moderate chelation strength differed (P<0.05) from iZn and the other two oZn sources. The RBV of ZnAA-L, ZnPRO-M and ZnPRO-H under the high phytate diet increased by 0.04, 0.11 and 0.22, respectively, compared to those under the low phytate diet. Results indicate that the oZn sources with moderate or strong chelation strength offer partial or complete resistance to interference from high dietary phytate during digestion; and the oZn with moderate chelation strength had a greater RBV with both low and high phytate diets than iZn or oZn sources with weak or strong chelation strength.

Randomized Placebo-Controlled Trial of Guava Juice as a Source of Ascorbic Acid to Reduce Iron Deficiency in Tarahumara Indigenous Schoolchildren of Northern Mexico

Objective: Assess the efficacy of a 10-week consumption of guava juice on the iron status of children with mild iron deficiency anemia.Methods: Ninety-five boarding school children aged 6–9 years identified as anemic were randomly allocated to receive 300 mL of natural guava juice containing ∼200 mg of ascorbic acid (AA) or placebo (guava-flavored juice free of AA) with the main meal (5 d/wk). Information about dietary intake was collected at weeks 3, 5, and 7 at school and household levels. Changes in hemoglobin (Hb) and plasma ferritin (PF) among the subsample iron deficient at baseline (n = 33) were the main outcomes.Results: Iron and phytic acid intakes at school and at home did not differ between groups. Baseline Hb and PF were 11.9 ± 0.5 g/dL and 8.2 ± 3.6 ng/mL for the guava, and 11.4 ± 1.1 g/dL and 7.4 ± 4.6 ng/mL for the placebo group (Hb: p = 0.08; PF: p = 0.31); at week 10 of the study, corresponding values were 13.1 ± 0.9 g/dL and 17.9 ± 10.3 ng/mL (n = 16), and 12.3 ± 1.3 g/dL and 15.4 ± 5.8 ng/mL (n = 12) (Hb: p = 0.05; PF: p = 0.21). With analysis of variance (ANOVA) for repeated measures, the guava group had 0.64 g/dL higher Hb (CI95, 0.18–1.11; p = 0.01) and 2.47 ng/mL higher PF (CI95, −1.04 to 5.98; p = 0.12) compared with the placebo group.Conclusion: Guava juice providing 200 mg AA at one meal on each school day had a marginal effect on Hb and PF concentrations in children consuming high-phytate diets fortified with iron.

Development of fortified biscuit using NaFeEDTA

Sodium iron ethylenediaminetetraacetic acetate (NaFeEDTA) is a promising iron fortificant for populations consuming high-phytate diets. It produces fewer organoleptic effects than other fortificants do, especially when the matrix of the food vehicle contains fat, and has a bioavailability two to four times higher than that of ferrous sulfate. This study investigated the effects of varying levels of NaFeEDTA (576-1152 mg kg(-1)) on the physicochemical and sensory characteristics of Petit Beurre biscuits. There were no significant differences in pH, ash, moisture and breaking strength values among all formulae. The iron content (7.2-14.4 mg per 100 g) of the biscuits increased with increasing fortificant level. During a 60 day storage period the peroxide value increased in both fortified and non-fortified formulae, especially after 28 days. The addition of NaFeEDTA had a significant (P < 0.05) effect on the colour, texture and flavour of fortified biscuits. Based on the range proposed for the use of NaFeEDTA as a fortification agent (10 mg iron and 67 mg EDTA per person per day), the results of this study reveal that 720 mg kg(-1) NaFeEDTA (9 mg iron per 100 g) is the optimum level for iron fortification in Petit Beurre biscuits.

A Reduced Phytate Diet Does Not Reduce Endogenous Fecal Zinc in Children on a Habitual High‐Phytate Diet

Ten Malawian children, ages 3 to 5 years, at risk for zinc deficiency and receiving a habitual maize-based high-phytate diet, received maize after phytate reduction for 40 days and had their endogenous fecal zinc (EFZ) measured using stable isotope techniques before and after phytate reduction. The phytate:Zn of the diet before reduction was 23.0 and afterward was 7.6. EFZ was similar before and after dietary phytate reduction, 1.15 ± 0.33 and 1.17 ± 0.16 mg/day, respectively. EFZ was not affected by dietary phytate in this population.

Relationship of calcium absorption with 25(OH)D and calcium intake in children with rickets

Nutritional rickets has long been considered a disease caused by vitamin D deficiency, but recent data indicate that inadequate dietary calcium intake is an important cause of rickets, particularly in tropical countries. Children with rickets due to calcium deficiency do not have very low 25(OH)D concentrations, and serum 1,25(OH)(2) D values are markedly elevated. Studies of Nigerian children with rickets demonstrated they have high fractional calcium absorption. A high-phytate diet was demonstrated to increase calcium absorption compared with the fasting state, and enzymatic dephytinization did not significantly improve calcium absorption. When given vitamin D, children with rickets have a marked increase in 1,25(OH)(2) D concentrations without any change in fractional calcium absorption. No positive relationship was found between fractional calcium absorption and serum 25(OH)D concentrations in children on low-calcium diets. More research is needed to understand the interaction between calcium and vitamin D and the role of vitamin D in calcium absorption.