Monitoring the stepwise phytate degradation in the upper gastrointestinal tract of pigs

The degradation and formation of inositol phosphates as affected by microbial phytase and gastrointestinal enzyme activities during the passage of phytate through the stomach and small intestine were studied in two experiments with four barrows and three collection periods. The degradation and formation of inositol phosphates were measured at the duodenal and ileal sites using Cr‐NDR, TiO₂ and Co‐EDTA as indigestible markers. In experiment 1, the effect of graded doses of Aspergillus niger phytase (0, 150 and 900 FTU Natuphos^® kg^?1), added to a maize–soybean meal‐based diet with very low intrinsic phytase activity on the degradation of phytate and the formation of inositol phosphates during digestion in the stomach and small intestine was investigated. In experiment 2, three different mixtures of inositol phosphates, produced by Aspergillus niger phytase, containing mainly high, intermediate and low phosphorylated inositol phosphates, were added to the same maize–soybean meal‐based diet as used in experiment I. The fate of the inositol phosphates during digestion in the stomach and small intestine was studied. Experiment 1 showed that the extent of phytate degradation was dependent of the graded dietary phytase activities. At high phytase activity (900 FTU kg^?1 of diet), strong phytate degradation occurred and the once hydrolysed phytate was rapidly dephosphorylated to lower inositol phosphates (mainly inositol di‐ and triphosphates). Intermediate inositol phosphates, such as inositol tetraphosphates, were quantitatively unimportant in duodenal and ileal digesta. At a phytase activity of 150 FTU kg^?1 of diet, a broader spectrum of intermediate inositol phosphates was determined, which was probably due to a slower breakdown of phytate. Experiment 2 showed as a predominant result that lower inositol phosphates such InsP₄ and InsP₃ were degraded, whereas InsP₂ accumulated in the duodenal and ileal digesta. No substantial disappearance of phytate from the stomach and small intestine was found when high concentrations of soluble phytate were added to the diet, which indicates that no substantial phytate absorption occurs in the upper part of the pig gut. Copyright © 2005 Society of Chemical Industry     

Peniophora lycii phytase is stabile and degrades phytate and solubilises minerals in vitro during simulation of gastrointestinal digestion in the pig

BACKGROUND: Microbial phytases (EC 3.1.3) are widely used in diets for monogastric animals to hydrolyse phytate present in the feed and thereby increase phosphorus and mineral availability. Previous work has shown that phytate solubility is strongly affected by calcium in the feed and by pH in the gastrointestinal (GI) tract, which may have an effect on phytase efficacy. An in vitro model simulating the GI tract of pigs was used to study the survival of Peniophora lycii phytase and the effect of the phytase on phytate degradation, inositol phosphate formation and mineral solubilisation during in vitro digestion of a 30:70 soybean meal/maize meal blend with different calcium levels. RESULTS: The phytase retained 76 and 80% of its initial activity throughout the gastric in vitro digestion. Total phytate hydrolysis by P. lycii phytase was in the same range at total calcium levels of 1.2 and 6.2 mg g^?1 dry matter (DM), despite very large differences in phytate solubility at these calcium levels. However, at 11.2 and 21.2 mg Ca g^?1 DM, phytate hydrolysis was significantly lower. The amount of soluble mineral was generally increased by P. lycii phytase. CONCLUSION: Stability of P. lycii phytase during gastric digestion was not found to be critical for phytate hydrolysis. Furthermore, original phytate solubility was not an absolute requirement for phytate degradation; phytate solubility seemed to be in a steady state, allowing insoluble phytate to solubilise as soluble phytate was degraded. This is new and interesting knowledge that adds to the current understanding of phytate–phytase interaction. Copyright © 2007 Society of Chemical Industry     

Supplementation of alkaline phytase (Ds11) in whole-wheat bread reduces phytate content and improves mineral solubility

Abstract: In this study, alkaline phytase was added to whole‐wheat bread and the phytate content and mineral profiles were compared to commercially available acidic phytase. At neutral pH, some phytate (approximately 20%) was degraded by endogenous phytase in wheat flour, while 40% of phytate was hydrolyzed by alkaline phytase DS11 and a 35% reduction was observed with acidic phytase. Most of the enzymatic activity occurred during the proofing stage, and the rate of reaction depended on pH. DS11 phytase effectively degraded the phytate level within a 30 min treatment at pH 7; however, at least 60 min was needed with acidic phytase to achieve the same hydrolysis level. Mineral profiles were also dramatically affected by the phytate reduction. The biggest increase was observed in Fe²⁺ by the phytase treatment. The Fe²⁺ content increased 10‐fold at pH 7 and 8‐fold at pH 5 with alkaline phytase DS11. Alkaline phytase DS11 was shown to be effective at phytate reduction in whole‐wheat bread preparation. Additionally, phytate degradation enhanced the mineral availability of bread.     

Laminarin in the dietary fibre concept

Dietary fibres consist of edible plant polysaccharides that are resistant to digestion and absorption in the human small intestine but undergo complete or partial fermentation in the colon. Seaweeds, notably Laminaria spp, are particularly rich in polysaccharides resistant to hydrolysis in the upper gastrointestinal tract and are, in consequence, considered as dietary fibres. Most of the carbohydrates from Laminaria spp are thought to be indigestible by humans. The main storage polysaccharide of these algae is laminarin, a β‐polymer of glucose. The aims of this work were, on the one hand, to compare various methods of extraction of laminarin by partial characterisation of the product obtained and, on the other hand, to study the fate of this polysaccharide and its effects in the gastrointestinal tract in order to determine its potential as a dietary fibre in human nutrition. Among four methods tested to extract laminarin, the best appeared to be a hot HCl‐based method. Human digestive enzymes did not hydrolyse laminarin, so this polysaccharide can be considered as a dietary fibre. After ingestion by rats, this polysaccharide was not found in faeces of these animals. It did not increase the intestinal transit and stool output in vivo, but it increased the contractile response of the stomach to acetylcholine in vitro. Copyright © 2004 Society of Chemical Industry     

Degradation of Phytate in Foods by Phytases in Fruit and Vegetable Extracts

ABSTRACT The ability of phytases from fresh fruits and vegetables to degrade phytate in foods was determined in vitro. In contrast to the more consistent presence of phytase in vegetables, only a few fruits contained detectable phytase activity. The highest phytase activities were 121 and 97 nmol min^‐1 g^‐1 in scallion leaves and avocado fruit, respectively. Avocado fruit also contained 0.14% phytate on a wet‐weight basis. Crude phytase extracts were incubated with ground corn tortillas or refried beans at 37 °C. Most of the phytate was degraded within 30 min by a 4‐fold excess by dry weight of scallion leaves. Avocado extracts incubated alone metabolized most of their endogenous phytate within 2 h.     

In vitro degradation and in vivo passage kinetics of carvacrol,thymol, eugenol and trans‐cinnamaldehyde along the gastrointestinal tract of piglets

BACKGROUND: The essential oils (EO) carvacrol, thymol, eugenol and trans‐cinnamaldehyde have well‐documented antimicrobial properties and offer therefore an alternative for the antimicrobial growth promoters in pig feeds. The aim of this work was to determine the degradation and kinetics of these EO along the gastrointestinal tract (GIT) of piglets, which is necessary information for correct application in pig feeds. RESULTS: None of these compounds was significantly degraded in in vitro simulations of pig gastric fermentation. Carvacrol and thymol were not degraded in jejunal simulations, but significant losses of up to 29% were found in caecal simulations. Eugenol and trans‐cinnamaldehyde showed a more pronounced degradation in jejunal and caecal simulations. A single dose mixed with feed (13.0, 13.2, 12.5 and 12.7 mg kg^?1 body weight for carvacrol, thymol, eugenol and trans‐cinnamaldehyde respectively) was given orally to piglets. Half‐lives in total digestive tract ranged between 1.84 and 2.05 h, whereby trans‐cinnamaldehyde showed the fastest disappearance. All of these EO were mainly and almost completely absorbed in the stomach and the proximal small intestine. Plasma concentrations (sum of free and conjugated compound) peaked at 1.39, 1.35 and 0.83 h for carvacrol, thymol and eugenol respectively and this was accompanied by high concentrations in urine. CONCLUSION: The four compounds were in vitro poorly degraded in the proximal segments of the GIT of piglets, but degradation is expected in more distal segments. In vivo, the EO were mainly and almost completely absorbed in the stomach and the proximal small intestine. Copyright © 2008 Society of Chemical Industry     

The degradation of phytate by microbial and wheat phytases is dependent on the phytate matrix and the phytase origin

BACKGROUND: Phytases increase utilization of phytate phosphorus in feed. Since wheat is rich in endogenous phytase activity it was examined whether wheat phytases could improve phytate degradation compared to microbial phytases. Moreover, it was investigated whether enzymatic degradation of phytate is influenced by the matrix surrounding it. Phytate degradation was defined as the decrease in the sum of InsP₆ + InsP₅. RESULTS: Endogenous wheat phytase effectively degraded wheat InsP₆ + InsP₅ at pH 4 and pH 5, while this was not true for a recombinant wheat phytase or phytase extracted from wheat bran. Only microbial phytases were able to degrade InsP₆ + InsP₅ in the entire pH range from 3 to 5, which is relevant for feed applications. A microbial phytase was efficient towards InsP₆ + InsP₅ in different phytate samples, whereas the ability to degrade InsP₆ + InsP₅ in the different phytate samples ranged from 12% to 70% for the recombinant wheat phytase. CONCLUSION: Wheat phytase appeared to have an interesting potential. However, the wheat phytases studied could not improve phytate degradation compared to microbial phytases. The ability to degrade phytate in different phytate samples varied greatly for some phytases, indicating that phytase efficacy may be affected by the phytate matrix. Copyright © 2011 Society of Chemical Industry     

Phytate content and phytate degradation by endogenous phytase in pea (Pisum sativum)

In order to rapidly reduce the content of inositol tri–hexaphosphates in pea flour by action of the endogenous phytase, raw materials as well as incubation conditions have been evaluated. The phytate (inositol hexaphosphate) content was analysed in 27 pea varieties; the influence of storage time and the difference in phytate content between the germ and the cotyledon were determined. Furthermore, degradation of inositol phosphates by the endogenous phytase enzyme was studied in pea flour, germ and cotyledon. To find the maximum phytate degradation, the effects of temperature and pH during pea flour incubation were investigated. The most efficient phytate degradation in pea flour incubation was achieved at pH 7.5 and 45 °C. At this condition an almost complete degradation of phytate and a 66% reduction in the sum of inositol hexa‐, penta‐, tetra‐ and triphosphates were reached in 10 h. The storage time of pea seeds or removal of the germ did not have a major effect on the phytate content. Since several inositol pentaphosphate isomers were produced during phytate degradation, it can be concluded that peas contain several phytate‐degrading enzymes, or one phytate‐degrading enzyme with unspecific initial hydrolysation pattern. © 2001 Society of Chemical Industry.     

Phytate hydrolysate induces circumferential F‐actin ring formation at cell–cell contacts by a Rho‐associated kinase‐dependent mechanism in colorectal cancer HT‐29 cells

Phytate (inositol hexa‐phosphate or IP6) possessing anticancer activity is hydrolyzed by phytase in intestinal microbes and the metabolites are distributed throughout the colon. Cellular circumferential F‐actin rings, which are involved in cell polarity and structure, are lost early during tumorigenesis. We investigated F‐actin ring formation by the phytate hydrolysate in colorectal cancer HT‐29 cells to explore the novel mechanisms underlying the phytate‐mediated anticancer function. The phytate hydrolysate, but not inositol or phytate, induced F‐actin ring formation with a peak at 10 min in the cells and was associated with phosphorylation of myosin regulatory light chain. F‐actin ring formation and myosin regulatory light chain phosphorylation by the phytate hydrolysate were suppressed by inhibitors of Rho‐associated kinase (ROCK), Janus kinase (JAK), c‐Jun N‐terminal kinase (JNK), and protein kinase Cδ (PKCδ). Activation of ROCK and JAK, but not JNK or PKCδ, was observed at 10 min and/or earlier after stimulation with the phytate hydrolysate. Altogether, the phytate hydrolysate induces circumferential F‐actin ring formation through a ROCK‐dependent myosin II activation in the HT‐29 cells, which requires JAK activation and basal activities of JNK and PKC. Hydrolysis products of phytate in the intestine may contribute to anticancer function of phytate.     

Phytase and Citric Acid Supplementation in Whole-Wheat Bread Improves Phytate-phosphorus Release and Iron Dialyzability

ABSTRACT Conditions were established for maximizing phytate breakdown in whole‐wheat flour (wwf) during bread baking and for assessing the effects of dephytinization on dialyzability of intrinsic and added iron in the bread. Three different sources of phytase (Aspergillus niger, A. fumigatus, and Escherichia coli) with various levels of citric acid (0 to 6.25 g/kg wwf) were used. Supplementing citric acid at 6.25 g/kg wwf enhanced phytate degradation catalyzed by intrinsic phytase from 42% in the untreated bread to 69% (P < 0.05). Supplementation of microbial phytase (285 units/kg) plus 3.125 or 6.25 g citric acid/kg wwf further enhanced phytate reduction up to 85%. Compared with the untreated bread, citric acid alone and the combination of citric acid and phytase enhanced total iron dialyzability by 12‐ and 15‐fold, respectively, while the combination of phytase, citric acid, and ascorbic acid improved total iron dialyzability in the mixture by 24‐fold.     

Determination of phytic acid in cereals – a brief review

Phytic acid is the major storage form for phosphorus in the cereal grains. It exists in the form of mixed salts of Ca–Mg–K (i.e. phytate), and occurs in many locations within the kernel. This form of phosphorus is not available to monogastric animals, including humans, because they lack the enzyme phytase in their digestive tract. In order to permit a better understanding of the functions and heritability of phytic acid, a literature search was conducted to review the development of procedures for the determination of phytic acid. Starting from a basic method of precipitation as insoluble ferric phytate in acid solution, the techniques for the determination of phytic acid have progressed through many kinds of instrumental methods such as colorimetric, synchronous fluorescence, isotachophoresis, high-performance ionic chromatography, and high-performance liquid chromatography.     

Phytate Hydrolysis by Phytase in Cereals; Effects on In Vitro Estimation of Iron Availability

Phytate (inositol hexaphosphate) hydrolysis by endogenous and exogenous phytases was studied for their effect on increasing iron availability in cereals. Wheat bran and whole meal flours of rye and oats were soaked at optimal conditions for phytase activity (55°C, pH 5) for different time intervals. Phytate and its degradation products were determined by HPLC and related to iron solubility under simulated physiological conditions. Small amounts of phytate (< lμmol/g) had a strong negative effect on iron solubility. When inositol hexa- and pentaphosphates of wheat bran and rye flour were completely hydrolyzed by activating endogenous phytase, iron solubility under simulated physiological conditions increased from 3 to 53% (wheat) and 5 to 21% (rye). Addition of wheat phytase to uncooked oatmeal increased iron solubility from 4 to 11 and in precooked to 18%, while endogenous phytase of uncooked oatmeal had less effect on phytate digestion and iron solubility.     

Stable current outputs and phytate degradation by yeast‐based biofuel cell

In this paper, we report for the first time that Candida melibiosica 2491 yeast strain expresses enhanced phytase activity when used as a biocatalyst in biofuel cells. The polarization also results in an increase of the yeast biomass. Higher steady‐state electrical outputs, assigned to earlier production of an endogenous mediator, were achieved at continuous polarization under constant load. The obtained results prove that the C. melibiosica yeast‐based biofuel cell could be used for simultaneous electricity generation and phytate bioremediation. In addition, the higher phytase activity obtained by interruptive polarization suggests a new method for increasing the phytase yield from microorganisms. Copyright © 2014 John Wiley & Sons, Ltd.     

The effect of germination on the phytase activity,phytate and total phosphorus contents of some Nigerian‐grown grain legumes

BACKGROUND: Grain legumes are under‐exploited as possible sources of phytase for the poultry industry. The current study was conducted to assess the effect of germination on phytase activities, phytate and total phosphorus content in samples of Nigerian‐grown grain legumes. The legumes screened were African yambean (AYB, Sphenostylis stenocarpa), lima bean (Phaseolus lunatus), pigeon pea (Cajanus cajan), cowpea (Vigna unguiculata) and groundnut (Arachis hypogea). RESULTS: Phytase activity was low in AYB, lima bean and pigeon pea but high in cowpea and groundnut. Phytate content ranged between 3.01 g kg^?1 and 8.95 g kg^?1 while total phosphorus content ranged between 2.63 g kg^?1 and 5.93 g kg^?1. The grain legumes with higher phytase activity recorded the lowest phytate and phosphorus content. During germination there was an initial 4‐fold to 35‐fold increase in phytase activity after 6–7 days of germination followed by a decrease until 10 days (P < 0.05). The increase in phytase activity during germination was accompanied by a significant reduction in phytate (P < 0.05) and a small but significant increase in total phosphorus. CONCLUSION: The increase in phytase activity and the accompanying decrease in phytate content could have a positive implication for the nutrition of poultry and ruminants and for the environment. Copyright © 2010 Society of Chemical Industry     

A model of phosphorus digestion and metabolism in the lactating dairy cow

A dynamic, mechanistic, compartmental model of phosphorus (P) digestion and metabolism was constructed in the Advanced Continuous Simulation Language using conservation of mass principles and mass action kinetics. Phosphorus was assumed to exist in 3 forms: inorganic (Pi), phytic acid (Pp), and organic (excluding phytic acid; Po). All 3 forms were assumed to be present in the digestive tract with absorption of Pi into blood. Inputs to the model were total P intake; Pp, Po, and Pi as proportions of total P; milk yield; rate of salivation (fixed at 239 L/d); and rate of liquid passage from the rumen (fixed at 198 L/d). The model was fitted to 2 experiments from the literature. Derived parameters were well defined by the data. With a mean observed P intake of 75 g/d, total tract P digestibility was 38%. Phytic acid P digestibility in the rumen was 74%, with no additional Pp digestion in the lower tract. Inorganic P and Po digestibility in the lower tract were 48 and 89%, respectively. Flows of Po and Pi from the rumen were 2.4 and 3.0 times greater than intake, respectively. The increase in Po was apparently due to microbial growth. The increase in Pi arose primarily from secretion of Pi into the rumen via salivation where 65% of absorbed P was recycled to the rumen. Milk synthesis used 30% of absorbed Pi, and 1% was excreted in urine. This research suggested that the primary regulation points for maintaining blood P were bone deposition and resorption and absorption from the intestine. However, because bone P balance was related to both dietary P intake and ruminal phytase activity, it is critical to achieve a better understanding of phytate digestibility across several feeds if dietary P is to be reduced below current requirements.     

植酸酶在食品中的应用

植酸酶是能够水解植酸盐的主要作为单胃动物饲料添加剂应用的一种磷酸酶，降低食品中植酸盐含量能够增加矿物质的生物利用率。近年来，植酸酶不断应用于食品的生产加工中。在食品生产中加入植酸酶，除了能提高矿物质和微量元素的生物利用率，还能改善终产品的质量和产量。目前，植酸酶在面包加工、植物蛋白分离物的生产和谷物糠的分馏中都有应用。     

植酸酶在食品中的应用

植酸酶是能够水解植酸盐的主要作为单胃动物饲料添加剂应用的一种磷酸酶,降低食品中植酸盐含量能够增加矿物质的生物利用率。近年来,植酸酶不断应用于食品的生产加工中。在食品生产中加入植酸酶,除了能提高矿物质和微量元素的生物利用率,还能改善终产品的质量和产量。目前,植酸酶在面包加工、植物蛋白分离物的生产和谷物糠的分馏中都有应用。     

Effect of enzymatic treatment on tannins and phytate in sorghum (Sorghum bicolor) and its nutritional study in rats

Sorghum is a cereal used as a food source by humans and animals. However, it presents antinutritional factors such as tannins and phytic acid, compounds that form complexes with proteins and minerals, respectively, decreasing sorghum’s digestive value. The purpose of this study was to apply tannase and phytase to sorghum and evaluate the effect on tannins and phytate level and the effect of the enzymatic treatment on Wistar rats. Tannin sorghum was treated with tannase and phytase, the effect of this treatment was measured in a study with rats, a group received a diet with raw sorghum and the other one a diet with treated sorghum. The enzymatic treatment was effective in reducing tannins and promoting the increase of inorganic phosphorus. The biological assay showed that the enzymatically treated sorghum was better than raw sorghum in the apparent digestibility of phosphorus, in the level of glucose, cholesterol and triacylglycerol. Treatment of the sorghum also resulted in lower activity of the enzymes aspartate aminotransferase and alanine aminotransferase in rat serum. The enzymatic treatment of sorghum could improve the nutritional value of this cereal while also decreasing environmental pollution.     

Recovery at the terminal ileum of some legume non‐nutritional factors in cannulated pigs

In order to exert an effect, either local or systemic, putative beneficial dietary substances have to survive at least to some extent the digestive process within the gastrointestinal tract. For that purpose, five castrated male pigs (100 ± 2 kg mean live b.w.) fitted with T‐shaped ileal cannulas were used to determine the recovery up to the terminal ileum of various non‐nutritional factors (NNF) from legumes (defatted soybean, raw lupin, raw chickpea and raw or autoclaved kidney beans). Kidney bean lectin (PHA) recovery within the small intestine ranged between 2.5 and 4.8 mg from 5.96 mg ingested. Two different methods were used to determine ileal digestibility of protease inhibitors (PI) in pigs. According to the enzyme‐linked immunosorbent assay (ELISA) method, apparent digestibility of Kunitz trypsin inhibitor and Bowman–Birk inhibitor for pigs fed the defatted soybean‐based diet were 0 and 58%, respectively. On the other hand, the apparent digestibility of PI along the small intestine, expressed in terms of trypsin inhibitory activity, was 96, 98 and 95% of activity in the diet, while data expressed in terms of chymotrypsin inhibitory activity were 95, 99 and 79% of activity in the diet for defatted soybean, raw chickpea and autoclaved kidney bean diets respectively. Differences found in ileal digestibility values of PI using both methodologies, ELISA and enzymatic inhibition, might be explained by the detection of inactive forms by specific antibodies. Intestinal apparent digestibility of phytate was 0% for defatted soybean and autoclaved kidney bean diets, whereas values for raw lupin and chickpea diets were 4.1 and 24.5%, respectively. In conclusion, significant amounts of several NNF survived the passage through the stomach and small intestine of cannulated pigs, which might have biological relevance. Copyright © 2006 Society of Chemical Industry     

Effect of grain source and exogenous phytase on phosphorus digestibility in dairy cows

Two experiments were conducted to determine P digestibility in lactating dairy cows fed corn or barley as grain sources. The first experiment utilized a replicated incomplete 5 × 4 Latin square design with 8 lactating Holstein cows fed diets containing either corn alone or corn in combination with one of 4 barley varieties that differed in chemical composition. Total tract digestibility of P ranged from 11 to 29% for diets containing the barley varieties and was approximately 35% for the corn diet. A second experiment compared P digestibility in cows fed diets containing corn or barley when exogenous phytase was added to the diets. Lactating Holstein cows (n = 16) were arranged in 4 replications of a Latin square with 2 grains (barley or corn), fed separately or with added exogenous phytase (427 phytase units/kg of total mixed ration and 4 periods of 21 d. Phytate P comprised about 50% of the total P (0.46% P) in the total mixed ration. The concentration of serum inorganic P was higher in cows fed diets with exogenous phytase (5.8 vs. 6.5 mg/dL in cows fed barley diets and 5.5 vs 6.0 mg/dL in cows fed corn diets). Using acid detergent lignin as an internal marker, hydrolysis of phytate P was increased by the exogenous phytase, and total P digestibility tended to be increased. In contrast to Experiment 1, in Experiment 2 there was no effect of grain source on P digestibility and total fecal P. Dry matter intake and efficiency of milk production were not affected by exogenous phytase or grain type. Although phytase activity occurs in the rumen, physical properties of the diet and ruminal passage rates may prevent total hydrolysis of phytate in the rumen of lactating cows. Thus, exogenous dietary phytase might improve P digestibility in dairy cows in some dietary situations.