Bioavailability of Zinc and Iron from Mature Winged Bean Seed Flour

The relative bioavailability of zinc and iron from mature winged bean (Psophocarpus tetragonolobus) flour was determined utilizing standard rat bioassay procedures. Weight gain of rats after 21 days and total bone (tibia) zinc resulting from zinc addition to the standard diet as zinc carbonate or from zinc endogenous to winged bean flour were compared. The relative bioavailability of winged bean zinc was calculated to be 85% (P < 0.05) and 93% (N.S.) when weight gain and log tibia zinc were the criteria of evaluation. The results of the hemoglobin repletion assay indicated that iron from winged bean was 89% (N.S.) as bioavailable iron from ferrous sulfate.     

Influence of high dietary iron as ferrous carbonate and ferrous sulfate on iron metabolism in young calves

Twelve intact male Holstein calves averaging 90 kg and 12 wk of age were fed one of three dietary treatments for 28 d. The diets were A) control, B) control plus 1000 ppm iron as ferrous carbonate, and C) control plus 1000 ppm iron as ferrous sulfate monohydrate. Calves were dosed orally on d 15 of the treatment period with 1 mCi of iron-59. Neither source of added iron had a significant effect on weight gains, feed consumption, hemoglobin, packed cell volume, serum total iron, serum total iron-binding capacity, unbound iron-binding capacity, serum copper, tissue copper, fecal dry matter, or a consistent effect on fecal pH. The ferrous carbonate had no significant effect on stable zinc or stable iron in any tissue studied. Calves fed ferrous sulfate had higher average stable iron in most tissues and significantly more in the small intestine. Tissue zinc was lower in spleen and pancreas of ferrous sulfate-fed calves. Both sources of added iron sharply reduced iron-59 in serum, whole blood, and body tissues. The reduction was substantially greater in calves fed the ferrous sulfate iron. Iron in ferrous sulfate had a higher biological availability than that in the ferrous carbonate; however, bioavailability of the ferrous carbonate iron appeared to be substantial and considerably more than that noted in previous studies in which a different source of ferrous carbonate was used. The maximum safe level of dietary iron is materially influenced by the source of iron with a higher tolerance indicated for ferrous carbonated than ferrous sulfate monohydrate.     

A COMPARATIVE STUDY OF IRON BIOAVAILABILITY IN RATS FROM SOYBEAN AND COTTONSEED PROTEIN ISOLATE DIETS

The purpose of this research was to determine the relative iron bioavailability from soybean and cottonseed protein isolates by using an iron depletion/repletion method. Iron stores of rats were depleted so that any iron introduced in the diet would be utilized at a maximum and linear rate for hemoglobin regeneration. A comparison of iron utilization from cottonseed and soy to the reference standard could then be made. Between 40 and 47% of the iron consumed from the soy diet was converted to hemoglobin iron. The cottonseed diets had a significantly lower (29 to 34%) conversion efficiency (P < 0.05) in comparison to casein but were not significantly different from the soy diets.     

Bioavailability of Iron in Iron-Fortified Fluid Milk

The bioavailability of iron in pasteurized and homogenized cow's milk was determined by the hemoglobin depletion-repletion technique using rats. A water soluble citrate phosphate iron complex (iron, 16.67%) was used to fortify milk (iron, 38 ppm). Results showed that iron in milk was as well available as that in ferrous sulfate (99% vs 100%); the same was true when the iron complex was tested as such (not added to milk). Thus, milk or milk components appear not to adversely affect the bioavailability of added iron under the conditions of this experiment.     

Iron bioavailability from ferric pyrophosphate in rats fed with fructan-containing yacon (Smallanthus sonchifolius) flour

The effects of inulin-type fructans (ITF)-containing yacon flour (YF) on Fe bioavailability from ferric pyrophosphate (FP) were evaluated in Fe-deficient rats using the Hb repletion efficiency (HRE) assay. Weanling male Wistar rats were fed a low-Fe diet (12 mg/kg) for 15 days followed by 2 weeks of Fe repletion with diets providing 35 mg Fe/kg as either ferrous sulphate (FS) or FP, supplemented with 7.5% ITF as either YF or Raftilose (RAF), a purified ITF. ITF increased caecal fermentation, whereas YF was more butyrogenic than RAF. ITF improved HRE in FP-fed rats, and those fed YF had a higher relative biological value compared with those fed FP and RAF. Liver Fe was increased by ITF, but only YF led to values similar to those in the FS group. It is observed that ITF increased caecal fermentation and Fe bioavailability. These effects were more pronounced when YF was the ITF source.     

Bioavailability of iron in goat milk compared with cow milk fed to anemic rats

Bioavailabilities of iron from dehydrated whole and skim goat milk were investigated using iron-deficient rats. Hemoglobin regeneration efficiencies were determined as the percent conversion of dietary iron into hemoglobin. The respective hemoglobin regeneration efficiencies for groups fed whole goat milk, whole cow milk, skim goat milk, and skim cow milk were 50.6, 13.1, 26.0, and 13.0%, indicating that iron bioavailability of goat milk was greater than cow milk. However, rats fed each milk had negative net increases in hemoglobin concentrations, implying that the iron contents of each milk were not adequate. For animals consuming whole goat milk supplemented with ferrous sulfate, the slope relating hemoglobin iron gained versus iron intake was .95. Respective bioavailabilities relative to ferrous sulfate were 54, 14, 28, and 14% for the four sources of milk. Iron bioavailability of goat milk is superior to cow milk when fed to anemic rats.     

Iron absorption and haemoglobin status of rats fed a ferrous bisglycinate‐fortified growing‐up milk

BACKGROUND: Infants and toddlers aged 6–24 months constitute one of the groups at highest risk of iron deficiency. A promising alternative for ferrous sulfate (FS) might be ferrous bisglycinate (FeAAC), which is less likely to cause sensory changes in the food vehicle. This work aims to compare the effect of FeAAC with that of FS, when added to a growing‐up milk, on the iron and haemoglobin status in weanling rats using a depletion–repletion model. RESULTS: After the repletion period no significant differences were found in iron absorption, Hb concentration, Hb iron, Hb regeneration efficiency (HRE), mean corpuscular volume (MCV), mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC), serum iron, total iron binding capacity (TIBC), transferrin saturation (TS), and ferritin between the group fed a growing‐up milk fortified with FS and the group fed one fortified with FeAAC. Furthermore, iron absorption, HRE, MCV, MCH, serum iron, and TS were significantly (P < 0.05) higher in groups fed either type of iron‐fortified growing‐up milk compared to the control group (AIN‐93G diet). CONCLUSION: A growing‐up milk supplemented with FeAAC showed an improvement in the iron absorption and haemoglobin status at the same level as those of FS. Copyright © 2009 Society of Chemical Industry     

Effect of Partial Phytate Removal and Heat upon Iron Bioavailability from Soy Protein-Based Diets

The effect of heat and partial phytate removal upon in vivo iron bioavailability from soy protein was studied by chick hemoglobin repletion. Iron repletion diets were formulated with unheated and heated soy protein isolates and phytate-reduced soy protein isolates, with and without iron supplementation. Heating at 120°C for 20 min, 75% phytate reduction and 20 mg/kg iron supplementation improved iron bioavailability by 65-77%, 6-11% and 10-17%, respectively. These beneficial effects were interpreted in terms of promoting protein and protein-Fe-phytate complex digestion and release of endogenous and added iron.     

Bioavailability to rats of iron from fortified grain amaranth flour

In this study, fortified and unfortified grain amaranth seed flour and FeSO₄ fortified casein diet as control were evaluated for their iron bioavailability. NaFeEDTA, ferrous fumarate, and FeSO₄-fortified grain amaranth were fed to Sprague Dawley weanling male rats. Iron intake, Hb Fe gain, Fe availability and binding capacity, serum iron, non-haem liver iron and relative biological value (RBV) were determined and values compared with FeSO₄-fortified casein control; all were improved greatly by fortification.
Relative biological values (RBV) were 0.40, 1.55, 1.75, 1.67 and 1.00 for animals receiving unfortified amaranth diet, those fed diet fortified with NaFeEDTA, ferrous fumarate, FeSO₄ and casein fortified with FeSO₄ respectively. RBV of the unfortified cereal was 40% of control suggesting perhaps low iron absorption from the amaranth cereal.
Based on the results of this study, amaranth cereal is ideal as a food vehicle for iron fortification. The iron fortificant of choice is ferrous fumarate.     

Comparison of methods to determine relative bioavailability of magnesium in magnesium oxides for ruminants

Two Mg balance trials were conducted with wethers to compare relative bioavailability of Mg in several Mg oxides with that of reagent grade sulfate as determined by different methods. In Experiment 1,600 ppm Mg as sulfate or four feed grade oxides varying in origin and particle size were added to a semi-purified basal diet (200 ppm Mg). Diets were fed at 800 g/d to 30 crossbred wethers during the 14-d trial and fecal and urinary collections were made during the last 7 d. In Experiment 2, the basal corn-soybean meal-cottonseed hull diet (1387 ppm Mg) was supplemented with 0, 700, 1400, or 2100 ppm added Mg as reagent grade sulfate or 1400 ppm Mg as three of the oxides from Experiment 1 and fed at 1000 g/d to 35 wethers. Urine was collected daily for 10 d and feces were collected on d 7 through 10. In Experiments 1 and 2, absorption of Mg from the oxide of brine origin and larger particle size distribution was lower than that from sulfate, but there was no difference in absorption for sheep fed oxides derived from sea water or calcined magnesite. In Experiment 2, urinary Mg excretion on d 4 and 5 of the collection was lower for sheep fed the brine oxide than for those fed sulfate or oxide from calcined magnesite. Urinary Mg excretion on d 4 and 5 following addition of 1400 ppm Mg to practical diets could be used to predict bioavailability of Mg.     

Iron Availability from Soy, Meat and Soy/Meat Samples in Anemic Rats With and Without Prevention of Coprophagy

The biological availability of iron from samples of soy proteins (nontextured, extruded and spun), meat (chicken and beef) and spun soy/meat combination products was compared to ferrous sulfate using a hemoglobin regeneration bioassay. Compared to ferrous sulfate (55%) iron availability from the various soy proteins ranged from 29-57%, for the meat samples 32-39% and for soy/meat combination products 61-92%. There was no significant improvement in iron availability by fortification with ferrous sulfate or ascorbic acid. Prevention of coprophagy in the anemic rats during the bioassay using aluminum anal cups produced varying degrees of reduction in iron availability for various samples and this effect clearly needs further investigation.     

Effect of Heat Treatment on Bioavailability of Meat and Hemoglobin Iron Fed to Anemic Rats

Efficiency of converting dietary iron from meat, bovine hemoglobin (HB) and ferrous sulfate into hemoglobin was investigated in anemic rats. Raw or autoclaved HB, and raw, autoclaved, boiled, or baked beef round, and ferrous sulfate were mixed into diets to give 36 mg Fe/kg diet. Heat treatments increased the efficiency of converting both HB and meat iron into hemoglobin by the anemic rats. Efficiencies of conversion were 23, 30, 33, 37, 37, 36 or 60 (LSD 0.05/0.01 = 4/6), respectively, for raw HB, autoclaved HB, raw meat, autoclaved meat, boiled meat, baked meat or ferrous sulfate. An in vitro measurement of iron availability in meat correlated poorly with bioavailability determined in rats. Cooking did not significantly affect the bioavailability of meat iron.     

Fortification of soy sauce using various iron sources: sensory acceptability and shelf stability

BACKGROUND: Soy sauces are available in different types and grades, which allows them to reach consumers of all socioeconomic groups. Ferric sodium ethylenediaminetetraacetic acid (NaFeEDTA) has been used for iron fortification of soy sauces in some countries, however, its high cost may make it unattractive to policymakers and industry. OBJECTIVE: We evaluated the feasibility of using more economical iron sources for iron fortification, with soy sauce of various types and grades used as a vehicle. METHODS: Seven iron sources were tested for their feasibility for fortification of four types of soy sauce: naturally fermented in the traditional style, naturally fermented according to large-scale industrial formulas 1 and 5, and chemically hydrolyzed at 5 mg per serving (15 mL, per Thailand's food labeling regulations). Either citric acid or sodium citrate was added at 0.1% as a chelator. RESULTS: Five iron sources--ferrous sulfate, NaFeEDTA, ferric ammonium citrate, ferrous lactate, and ferrous gluconate--did not significantly affect the sensory qualities of the product over a period of 3 months (p > .05). Ferrous fumarate and ferrous bisglycinate caused unacceptable precipitation. Less than 3% of 260 and 306 commonly cooked foods out of 871 and 772 preparations using soy sauces fortified with NaFeEDTA and ferrous sulfate, respectively, were found to be different from normal with regard to sensory qualities. The cost of fortification was US 0.22 cents to US 3.28 cents per bottle (700 mL). CONCLUSIONS: Both naturally fermented and chemically hydrolyzed soy sauces could be fortified with all five iron sources. Ferrous sulfate is the most appropriate source because of its low cost and acceptable sensory characteristics. Soy sauce is a promising vehicle for iron fortification, however, the bioavailability of iron in the products examined here needs to be evaluated under normal use conditions.     

Effect of excess iron in milk replacer on calf performance

Milk replacers containing 100, 500, 1000, 2000, or 5000 ppm iron were fed to 3-d-old calves for 6 wk to estimate the lowest amount of dietary iron (added as ferrous sulfate) that would reduce calf performance. Calves tolerated all iron treatments except 5000 ppm. At this intake calves showed reduced weight gains, DM intake, feed efficiency, and digestibility of DM and protein. There were no other signs of iron toxicity and no gross abnormalities were found on postmortem examination. Percent of dietary iron in feces increased with higher dietary iron and ranged from 65 to 84%. Elevated iron intakes caused relatively small increases in iron concentration of blood plasma, bile, kidney, heart, and muscle but marked increased in spleen and liver iron, particularly in liver for the 2000 and 5000 ppm treatments. At 100 ppm iron intake, nonheme iron in liver, spleen, and kidney was composed of similar proportions of ferritin and hemosiderin, but at 5000 ppm iron intake, hemosiderin predominated in these tissues. Thus, the preruminant calf tolerated between 2000 and 5000 ppm iron in milk replacer. At toxic iron intake, calf performance and feed efficiency were reduced; there was a characteristic change to higher liver than spleen iron; and hemosiderin became the predominant iron storage compound in both tissues.     

Iron bioavailability from Amaranthus species: 2—Evaluation using haemoglobin repletion in anaemic rats

Initial screening of 46 lines from 12 species of Amaranthus indicated wide variation in total iron (Fe) and small but significant differences in bioavailable Fe when estimated by an in vitro assay. To verify if differences in bioavailable Fe detected by in vitro assay were biologically significant, one line from each species A tricolor, A hypochondriacus and A cruentus was evaluated using a haemoglobin (Hb) repletion assay with anaemic rats. Anaemic rats were fed treatment diets in which almost all Fe was provided by amaranth lines, and Hb gains were compared to those of rats fed control FeSO₄ diets. Slope ratio analysis indicated that Fe supplied by A hypochondriacus had a greater relative bioavailability (61%) than from A tricolor (44%), when compared to FeSO₄ (100%). However, A tricolor contained a higher concentration of total Fe (690 ppm) in the leaf material. When the same amount of amaranth was added to individual diets (30 g kg⁻¹ diet), analysis of Hb repletion efficiency (HRE) indicated that A tricolor supported the largest Hb gain of the three lines, despite having the lowest relative bioavailability compared to A hypochondriacus and A cruentus. Despite a lack of correlation between total and bioavailable Fe, these results suggest future efforts should focus initially on enhancing total Fe concentration of green leafy vegetables (GLVs), until the forms of bioavailable Fe in these plant materials are identified. Rat bioassay did confirm relative differences in bioavailable Fe estimated by the in vitro assay, supporting use of the in vitro assay in breeding programmes focused on improving Fe nutritional quality of GLVs. © 1998 Society of Chemical Industry     

Iron-Enriched Bread: Interaction Effect of Protein Quality and Copper on Iron Bioavailability

These studies examined the bioavailability of iron in iron-enriched breads. The test breads also contained added protein in the form of gluten, soy or nonfat dry milk. Bioavailability was assessed based on net hemoglobin synthesis in rats initially made iron deficient and then fed bread-based diets containing 38.5 ppm iron (NRC requirement for rat, 35 ppm) and 3.75, 5.00, or 6.25 ppm copper (NRC requirement for rat, 5 ppm). More hemoglobin was synthesized on milk-supplemented (83 mg/mg iron) and on soy-supplemented (85 mg/mg iron) bread diets than on gluten-supplemented (59 mg/mg iron) bread diets. Copper appeared to have no influence on hemoglobin regeneration or on hepatic iron accumulation under the conditions of this experiment.     

Effect of processing on iron bioavailability of extruded bovine lung

The iron bioavailability of extruded and non-extruded lung products was compared with that of ferrous sulfate by the haemoglobin regeneration method. Extrusion was performed in a laboratory extruder (L/D 20:1) at several processing temperatures and moisture contents of the feed (115–160 °C; 16–30% moisture) with screw (4:1 compression ratio) speed fixed at 200 rpm. These conditions included the optimum observed for lung texturization. Bioavailability of iron was determined as efficiency of haemoglobin regeneration in rats fed bovine extruded lung-based diets, compared with non-extruded lung and casein standard diets. The results showed that iron bioavailability was high and comparable with ferrous sulfate standard, irrespective of the extrusion conditions adopted. These results showed that extruded lung can be used as a good iron source, even if processed in conditions deleterious for other nutrients.     

蛋氨酸螯合铁对大鼠肝脏物质代谢相关基因表达的影响

研究缺铁日粮中补充蛋氨酸螯合铁与硫酸亚铁对大鼠铁利用及肝基因表达的影响。20只SD断奶大鼠,建立缺铁大鼠模型,然后均分成两组,分别饲喂加入等量铁(35mg/kg)的蛋氨酸螯合铁和硫酸亚铁日粮,补铁后4、7d后测定体重、血红蛋白,组织器官铁含量及血清总铁结合力;并提取大鼠肝组织总RNA,用Afymetrix基因芯片进行基因表达分析,研究硫酸亚铁与蛋氨酸螯合铁对缺铁大鼠物质代谢基因表达的差异。结果表明,蛋氨酸螯合铁组大鼠增重明显高于硫酸亚铁组,血红蛋白、总铁结合力含量有升高趋势。与硫酸亚铁组比较,蛋氨酸螯合铁组肝组织珠蛋白与转铁蛋白合成相关基因,以及胆固醇合成,脂肪代谢、ATP合成相关基因明显上调。补充蛋氨酸螯合铁动物铁代谢和物质代谢存在显著差异。     

Effects of high but nontoxic dietary manganese and iron on their metabolism by calves

Sixteen male Holstein calves were fed one of four diets for 18 days in an experiment consisting of 0 and 1000 ppm supplemental manganese and 0 and 1000 ppm added iron as manganese carbonate and ferrous carbonate. The control diet contained 55 ppm manganese and 220 ppm iron. All calves were dosed orally 48 h prior to sacrifice with 500 muCi of manganese-54. Small intestinal iron was less in calves fed a high manganese diet, a possible interaction of these two elements at the absorption site. Feeding a high manganese diet tended to decrease iron (total) concentrations in liver and pancreas. When the high manganese diet was supplemented with additional iron, antagonistic effects of manganese on iron were eliminated. Neither iron nor manganese concentrations in tissues were affected by an increase of dietary iron. Manganese-54 content of tissue was reduced by the high manganese diet but was not affected by dietary iron. Total manganese and iron in feces fairly closely reflected dietary intake of each element with no evidence of interaction. Calves fed the high iron diet excreted less manganese-54 in their feces over 2 days. Total iron in blood serum was not affected significantly by the dietary treatments.     

Supplementation of Copper as Copper Sulfate or Copper Proteinate for Growing Calves Fed Forages Containing Molybdenum

Holstein calves (age > 12 wk old) were assigned to dietary treatments of 1) no supplemental copper, 2) copper proteinate, or 3) copper sulfate. The copper supplements were incorporated into premixes and added to a pelleted concentrate. The concentrates were fed at 1.8 kg per head per d and contained 5, 19, or 19 ppm copper and .6 ppm molybdenum by analysis. All calves were fed a grass hay free-choice, which contained 1 ppm copper and 5 ppm molybdenum. Ratios of copper to molybdenum were .9, 2.8, and 2.8 for diets 1, 2, and 3, respectively. Copper concentrations in plasma were significantly greater at wk 12 in calves fed copper proteinate than control or calves supplemented with copper sulfate. Liver copper also was higher at wk 12 in calves fed copper proteinate. Final body weights, plasma zinc, plasma iron, hemoglobin, and hematocrit were not affected by treatment. Bioavailability of dietary copper from copper proteinate was greater than from copper sulfate for calves fed diets containing molybdenum.