Dietary effects on inositol phosphate breakdown in the crop of broilers

BackgroundThe degree to which storage conditions and duration affect phytase activity and inositol phosphates (InsP) was evaluated in wheat. Three wheat cultivars were stored as whole or ground kernels at 20, 7, and −18°C for 13, 48, 118, 188, 265, and 349 days. Samples were analyzed for InsP3‐6 concentration and phytase activity.ResultsThe InsP6 concentration of whole wheat kernels stored at −18 and 7°C did not differ from that at time point 0. Storage of whole kernels at 20°C significantly reduced the InsP6 concentration at days 48, 188, 265, and 349, by up to 8.4%. The InsP6 concentration of ground wheat samples was reduced by up to 23.6% until day 349. The lower InsP isomers Ins(1,2,3,4,5)P5 and Ins(1,2,4,5,6)P5 were detected only at a storage temperature of 20°C and at day 118 or later. Phytase activity did not change over time in ground kernels stored at −18 and +7°C but was decreased in ground kernels at 20°C and in whole kernels independent of temperature. Probable cultivar effects were found regarding phytase activity over time, dependent on grinding and storage temperature.ConclusionTo avoid loss of InsP6 content, wheat samples should be stored as whole kernels at or below 7°C. Phytase activity is more stable in ground samples than in whole kernels. However, some cultivars likely are more prone than others to storage effects.

SummaryPhytase activity was investigated in 13 lichen species using a novel assay method. The work tested the hypothesis that phytase is a component of the suite of surface‐bound lichen enzymes that hydrolyse simple organic forms of phosphorus (P) and nitrogen (N) deposited onto the thallus surface.Hydrolysis of inositol hexaphosphate (InsP6, the substrate for phytase) and appearance of lower‐order inositol phosphates (InsP5–InsP1), the hydrolysis products, were measured by ion chromatography. Phytase activity in Evernia prunastri was compared among locations with contrasting rates of N deposition.Phytase activity was readily measurable in epiphytic lichens (e.g. 11.3 μmol InsP6 hydrolysed g−1 h−1 in Bryoria fuscescens) but low in two terricolous species tested (Cladonia portentosa and Peltigera membranacea). Phytase and phosphomonoesterase activities were positively correlated amongst species. In E. prunastri both enzyme activities were promoted by N enrichment and phytase activity was readily released into thallus washings. InsP6 was not detected in tree canopy throughfall but was present in pollen leachate.Capacity to hydrolyse InsP6 appears widespread amongst lichens potentially promoting P capture from atmospheric deposits and plant leachates, and P cycling in forest canopies. The enzyme assay used here might find wider application in studies on plant root–fungal–soil systems.

Three phytase (EC 3.1.3.26) isoforms from the roots of 8-d-old maize (Zea mays L. var Consul) seedlings were separated from phosphatases and purified to near homogeneity. The molecular mass of the native protein was 71 kD, and the isoelectric points of the three isoforms were pH 5.0, 4.9, and 4.8. Each of the three isoforms consisted of two subunits with a molecular mass of 38 kD. The temperature and pH optima (40[deg]C, pH 5.0) of these three isoforms, as well as the apparent Michaelis constants for sodium inositol hexakisphosphate (phytate) (43, 25, and 24 [mu]M) as determined by the release of inorganic phosphate, were only slightly different. Phytate concentrations higher than 300 [mu]M were inhibitory to all three isoforms. In contrast, the dephosphorylation of 4-nitrophenyl phosphate was not inhibited by any substrate concentration, but the Michaelis constants for this substrate were considerably higher (137-157 [mu]M). Hydrolysis of phytate by the phytase isoforms is a nonrandom reaction. D/L-Inositol-1,2,3,4,5- pentakisphosphate was identified as the first and D/L-inositol-1,2,5,6-tetrakisphosphate as the second intermediate in phytate hydrolysis. Phytase activity was localized in root slices. Although phosphatase activity was present in the stele and the cortex of the primary root, phytase activity was confined to the endodermis. Phytate was identified as the putative native substrate in maize roots (45 [mu]g P g-1 dry matter). It was readily labeled upon supplying [32P]phosphate to the roots.

Changes in phytic acid content, activity of phytase and α-amylase in rye breads were determined during rye bread making. The activity of phytase is highest in grain and flour whereas the activity in the sourdoughs is almost the half of the activity in the flour. The activity was unchanged in the dough after mixing and proofing. Degradation of phytic acid (IP6) into lower inositol phosphates and free phosphate is almost completed during the production of rye bread with long fermentation time whereas the degradation is less completed when whole grains are included in the recipe. In rye bread made from milled rye (DB00), 99% of IP6 is degraded and IP3 becomes the dominating inositol phosphate in this bread type presumably resulting in a high level of bioavailable minerals. In rye bread made with 30% grains (SB30), 94% of the IP6 content was reduced with IP4 and IP3 being the dominating lower inositol phosphates. In rye bread made with 50% whole grains (KB50) the degradation of IP6 was 82%, and the three inositol phosphates IP5, IP4 and IP3 were found in equal amount in this bread type. Due to significant amounts of phytic acid and remaining IP5, some of the minerals might not be available for human absorption after consumption of this bread type.

Effect of diets containing enzyme supplements and microwave-treated or untreated wheat on inositol phosphates in the small intestine of broilers

Two experiments (Exp.) with ileally cannulated growing barrows were conducted. The concentrations of positional inositol phosphate (InsP) isomers in ileal digesta and feces were determined, as well as the prececal and total tract phytate (InsP6) hydrolysis, and digestibility of dry matter, P, Ca, nitrogen, and gross energy. Prececal amino acid (AA) digestibility and digestive enzyme activities in ileal digesta were also studied. In both Exp., pigs had an initial body weight (BW) of 28 kg and were completely randomized to a Double Latin Square Design with eight pigs, four diets, and three periods of 12 d each. Feces and ileal digesta were collected for 5 d and 2 d, respectively. Pigs were housed individually in stainless steel metabolic units. Water was available ad libitum and feed was provided two times daily at an amount of 4% of mean BW. In Exp. 1, pigs received a corn–soybean meal (SBM)-based diet that was supplemented with 0, 750, 1,500, or 3,000 FTU of a microbial phytase/kg diet. In Exp. 2, pigs were allotted to a 2 × 2 arrangement of diets based on corn and SBM or an SBM-rapeseed cake (RSC) mix and phytase supplementation at 0 or 1,500 FTU/kg of diet. In ileal digesta of pigs fed without the phytase supplement, the dominating InsP isomers beside InsP6 were InsP5 isomers. The InsP pattern in ileal digesta changed with the inclusion of microbial phytase in both Exp., as there was a remarkable increase in Ins(1,2,5,6)P4 concentration (P < 0.001). In both Exp., the myo-inositol concentration in ileal digesta was greater upon phytase addition (P < 0.001). Without phytase supplementation, prececal and total tract P digestibility were low, whereas hardly any InsP6 was excreted in feces. There was no difference between prececal and total tract P digestibility values. For most AA studied in Exp. 2, prececal digestibility was lower (P < 0.01) when the diet contained RSC. However, phytase supplementation did not significantly affect prececal AA digestibility in both Exp. The present study showed that InsP6 disappearance by the end of the ileum can be increased up to around 90% in SBM- and SBM–RSC-based diets when microbial phytase is supplemented, but prececal P digestibility hardly exceeded 60%. The study confirms that pigs cannot benefit from a remarkable InsP6 degradation in the hindgut.

Distribution of phytase activity, total phosphorus and phytate phosphorus in legume seeds, cereals and cereal by-products as influenced by harvest year and cultivar

Phytase activity in the small intestinal brush border membrane of the chicken

Phytases catalyze the hydrolysis of phosphomonoester bonds in phytate, thereby releasing lower forms of myo-inositol phosphates and inorganic phosphate. Phytase enzyme preparations have a wide range of applications in animal and human nutrition. The addition of phytate-degrading enzyme can improve the nutritional value of plant-based foods by enhancing protein digestibility and mineral availability through phytate hydrolysis during digestion in stomach or during food processing. 30 strains of potential phytate-degrading enzymes bacteria isolated from Malaysian maize plantation were cultivated in Luria Bertani (LB) and Luria Bertani + Rice Bran (LBRB) media for 5 days and were analyzed for phytase activity. The 6 strains with highest activity were chosen for species identification. Two set of broad-range 16S rRNA PCR primers were used for genotypic identification. ASUIA279 was the strain that had has the highest phytase activity in LBRB followed by ASUIA271, ASUIA138, ASUIA260, ASUIA243 and ASUIA30. The genotypic technique revealed Pantoea stewartii ASUIA271, Enterobacter sakazakiiASUIA279, Bacillus cereus ASUIA260, Bacillus subtilis ASUIA243, P. stewartiiASUIA138 and B. cereus ASUIA30. Key words: Bacterial phytase, rice bran, production, genotypic.

In vitro hydrolysis of phytate in canola meal with purified and crude sources of phytase

Phytic acid is an antinutritional factor that forms 1–2% of most of the seeds and their co-products representing more than 60% of their total phosphorus. Monogastric and agastric animals are unable to utilize phytate phosphorus either due to lack of or insufficient amount of phytate degrading enzymes. Phytases (myo-inositol hexakisphosphate-phosphohydrolase) are a special class of phosphatases that catalyze the hydrolysis of phytic acid in a stepwise manner to lower inositol phosphates, myo-inositol and inorganic phosphate. Phytases are found naturally in plants and microorganisms and a sizeable number of phytases have been purified and characterized from various fungi, yeasts and bacteria. The present investigation involves studies on the effect of moisture content, pH value and different media ingredients such as carbon, nitrogen, and surfactants on the production of phytase by the fungus Aspergillus ficuum DSM 932 in solid-state fermentation (SSF) using rice bran as substrate. The production of phytase by SSF was favored, when the fungus was grown at a moisture content of 60% and pH 7.0, resulted in a phytase activity of 5.2 units/g dry substrate. There was a 20% increase in phytase yield in the presence of sucrose in SSF medium, while glucose and fructose were not effective in enhancing the phytase activity when used individually. Yeast extract was found to be a favorable nitrogen source for phytase production by SSF, which resulted in a 20% increase in phytase activity. There was no significant effect in increasing phytase production with the use of either soy peptone or tryptic soy as nitrogen source. Approximately 30% inhibition in phytase activity was shown in the presence of the surfactant Tween-80 or Triton X-100 in the SSF. By supplementing rice bran with sucrose and yeast extract, and performing the SSF in tray bioreactors, a phytase activity of 6.76 units/g dry substrate could be obtained. Keywords: phytase, solid-state fermentation, Aspergillus ficuum , nutritional factors, rice bran

![][1] The old adage that pregnant women eat for two might be more true than ever before in the light of recent research into diet and the control of gene expression. The link between the diet of pregnant women—and, to some extent, men—during pre‐conception and the health of the fetus has been viewed mostly in terms of major risk factors such as smoking or substance abuse. However, epidemiological and molecular research is revealing a more complex and subtle picture of how a pregnant woman's eating behaviour influences the expression of her own—and possibly her fetus's—genes, and thus the long‐term health of her children. “Type II diabetes, heart disease due to obesity, insulin resistance, and hypertension are the diseases most strongly associated with maternal diet during pregnancy,” said Karen Lillycrop, who specializes in perinatal nutrition at the University of Southampton in the UK. In addition, there is growing evidence that dietary effects, which can alter the expression and control of genes, might even have been a driving force for human evolution. A recent study revealed that the greatest divergence between the genomes of humans and chimpanzees is found among genes that control metabolism and are closely associated with diet (Somel et al , 2008). The mechanisms that allow the genome to interact with environmental factors, such as diet, are epigenetic changes—a concept first proposed by the British biologist Conrad Waddington (1905–1975) in 1942 to describe the interplay between genes and the environment in determining the phenotype of an organism. Further research since Waddington's time has shown that epigenetic changes not only take place during embryonic development, but also throughout the lifetime of an organism. The same mechanisms—notably DNA methylation and histone modification—have a role in the acquisition and maintenance of epigenetic changes induced by dietary or other environmental factors. In fact, they … [1]: /embed/graphic-1.gif

Two experiments were carried out to examine the influence of a Trichoderma viride enzyme complex [cellulase, endo-β-(1:3)(1:4)-glucanase, xylanase] on nutrient utilization and production parameters of laying hens. In exp. 1, the influence of extrusion (110 °C, 20 s) and dietary enzyme addition on the nutritive value of the diet was tested. Dietary treatments were as follows: M and MR, unprocessed feed, plus or minus enzyme; E, feed extruded without enzyme; ER-1, feed extruded with enzyme; ER-2, enzyme added after extrusion. Diets were fed in mash form. Partial inactivation of the enzyme took place as indicated by a significant difference in energy use in groups ER-1 and ER-2 (73 vs. 75%). According to the enzyme-affected changes of the feed extract viscosity, 65% of the enzyme initial efficacy were lost as a result of extrusion. Nevertheless, the addition of enzyme before extrusion (ER-1) was not without effect, as birds fed the ER-1 diet had improved energy (73 vs. 71%) and fat utilization (89 vs. 85%) as compared with those fed the extruded unsupplemented diet (E). Extrusion decreased feed AME content by 0.3 MJ kg−1. A significant interaction between processing and enzyme for energy and fat utilization indicated a greater beneficial effect of enzyme in extruded feed. Experiment 2 was arranged in a same way as exp. 1, with the exception that pelleting (70 °C) replaced the extrusion process. Feed extract viscosity measurements revealed that pelleting reduced initial enzyme efficacy by 52%. Despite this, enzyme improved nutrient utilization in unprocessed and pelleted diet to the same extent, and no further improvements were observed by supplementation of the feed after processing. Pelleting itself did not affect nutritive value of the feed. Key words: Enzyme supplementation, laying hens, feed processing

Several neurotransmitters activate polyphosphoinositide (PPI) hydrolysis in CNS neurons as the first step of a transmembrane signalling cascade that may lead to neuronal circuit modulation. Muscarinic and quisqualate receptor-triggered PPI hydrolysis was investigated in neuronal primary cultures. A clear increase in inositol phosphates (Ins-Ps) was detected as early as 15 s after the agonist addition; at this time, the increases of inositol 1,4,5-trisphosphate (measured by HPLC) were relatively larger with respect to the other Ins-Ps. Ins-P accumulation was maintained in part in a Ca2+-free medium, excluding that Ca2+ entry is the fundamental step of the receptor-induced PPI hydrolysis. Acute cell pretreatment with phorbol dibutyrate, an activator of protein kinase C, was able to inhibit 50% of the response to carbachol, and almost completely the quisqualate effect, suggesting a negative feedback modulation by the enzyme. Finally, pertussis toxin failed to inhibit muscarinic responses, whereas it blocked greater than 70% of the quisqualate stimulation. The two receptors therefore appear coupled to phosphodiesterase by two different G proteins. The comparison of the results obtained by stimulating the two receptor systems suggests that the generation of the same intracellular signal at two distinct receptor types may occur by different coupling mechanisms, and be differently regulated even in the same neuronal preparations.

Dietary Effects on Coagulation Factor VII Vary across Genotypes of the R/Q353 Polymorphism in Elderly People