Dietary Iron Levels Research Articles

High Iron Consumption Modifies the Hepatic Transcriptome Related to Cholesterol Metabolism.

Iron supplementation is a common method for alleviating symptoms of iron deficiency, but excessive iron intake may lead to systemic copper deficiencies and hypercholesterolemia. In our study, we explored the intricate relationship between dietary iron and copper levels and their impact on cholesterol metabolism. Using a rat model, we conducted dietary interventions with varying iron and copper concentrations and analyzed hepatic transcriptomes. High iron intake coupled with low copper intake induced hypercholesterolemia and altered the expression of genes associated with cholesterol and lipid metabolism, thereby, exacerbating cardiovascular disease risks. Conversely, copper supplementation mitigated these hepatic gene expression alterations, suggesting that dietary copper plays a role in cholesterol regulation. Transcriptomic analysis revealed significant upregulation of genes involved in cholesterol synthesis and antioxidative pathways in response to high iron intake, while genes involved in cholesterol elimination were downregulated. Furthermore, high iron consumption was associated with cellular apoptosis and the activation of cholesterol synthesis. Our findings underscore the importance of balanced iron and copper intake in cholesterol homeostasis and highlight the potential of copper supplementation for mitigating iron-induced hypercholesterolemia.

Source and level of dietary iron influence semen quality by affecting inflammation, oxidative stress and iron utilization levels in boars

BackgroundBoars fed a mixed form of inorganic and organic iron in excess of the NRC recommended levels still develop anemia, which suggested that the current level and form of iron supplementation in boar diets may be inappropriate. Therefore, 56 healthy Topeka E line boars aged 15–21 months were randomly divided into 5 groups: basal diet supplemented with 96 mg/kg ferrous sulfate (FeSO4) and 54 mg/kg glycine chelated iron (Gly-Fe, control); 80 mg/kg or 115 mg/kg Gly-Fe; 80 mg/kg or 115 mg/kg methionine hydroxyl analogue chelated iron (MHA-Fe, from Calimet-Fe) for 16 weeks. The effects of dietary iron supplementation with different sources and levels on semen quality in boars were investigated.Results1) Serum Fe and hemoglobin concentrations were not affected by reduced dietary iron levels in the 80 mg/kg or 115 mg/kg Gly-Fe and MHA-Fe groups compared with the control group (P > 0.05). 2) Serum interleukin-6 (IL-6) and sperm malondialdehyde (MDA) levels in the 80 mg/kg or 115 mg/kg MHA-Fe groups were lower than those in the control group (P < 0.05), and higher serum superoxide dismutase levels and lower MDA levels in the 115 mg/kg MHA-Fe group (P < 0.05). 3) Boars in the 80 mg/kg or 115 mg/kg Gly-Fe and MHA-Fe groups had lower serum hepcidin (P < 0.01), ferritin (P < 0.05), and transferrin receptor (P < 0.01) concentrations, and boars in the 115 mg/kg MHA-Fe group had higher seminal plasma Fe concentrations compared with the control group. 4) Boars in the 80 mg/kg and 115 mg/kg MHA-Fe groups had lower abnormal sperm rate and in situ oscillating sperm ratio compared to the control group at weeks 12 and/or 16 of the trial. However, the effect of Gly-Fe on improving semen quality in boars was not evident. 5) Serum IL-6 level was positively correlated with hepcidin concentration (P < 0.05), which in turn was significantly positively correlated with abnormal sperm rate (P < 0.05). Furthermore, significant correlations were also found between indicators of iron status and oxidative stress and semen quality parameters.ConclusionsDietary supplementation with 80 mg/kg or 115 mg/kg MHA-Fe did not induce iron deficiency, but rather reduced serum inflammatory levels and hepcidin concentration, alleviated oxidative stress, increased body iron utilization, and improved semen quality in adult boars.

Effect of dietary iron (Fe) supplementation on growth performance, hematological parameters and anti-oxidant responses of coho salmon Oncorhynchus kisutch (Walbaum, 1792) post-smolts

Effects of graded dietary iron (Fe) levels on coho salmon Oncorhynchus kisutch (Walbaum, 1792) post-smolts were assessed by determining the growth performance, Fe deposited in tissue, liver and serum antioxidant and immunity responses. Six experimental diets containing graded Fe (FeSO4·7 H2O as a Fe source) levels of 23.70, 42.40, 63.80, 89.30, 102.70 and 125.70 mg/kg were made and fed to three replicate groups of fish. A total 180 coho salmon post-smolts (188.28 ± 0.40 g) were randomly distributed to 18 floating cages (water volume 1000-L) with a flow-through system for 10 weeks, and fed three times daily until satiation. The results showed that the final body weight (FBW) and specific growth rate (SGR) were increased (p < 0.05) with increasing Fe content (from 23.70 to 89.30 mg/kg) in the diet, and significantly decreased (p < 0.05) in these traits were recorded when dietary Fe supplementation was further increased (from 89.30 to 125.70 mg/kg). However, feed conversion ratio (FCR) showed the opposite trend. Survival rate, morphological indices, and body proximate compositions did not differ significantly among the groups (p > 0.05). Nevertheless, the Fe contents in the whole body and muscle exhibited a steady rise (linear, p < 0.05), meanwhile, the liver Fe content significantly increased with increasing dietary Fe levels (linear and quadratic, p < 0.05). Increasing dietary Fe levels increased (p < 0.05) the hemoglobin (Hb), erythrocyte counts and hematocrit. In serum, lysozyme activity was significantly increased in 89.30 mg/kg diets ( p < 0.05). There was a significant increase in liver and serum superoxide dismutase (SOD) and catalase activities in response to the Fe levels in the diet, whereas a significant quadratic decrease in malondialdehyde levels (p < 0.05). Quadratic regression analysis of SGR and FCR against dietary Fe levels indicated that the optimal dietary Fe requirements were estimated to be 100.00 mg/kg and 104.17 mg/kg. Broken-line model analyses of the hepatic Fe content and SOD activity, the Hb content in the blood, and serum SOD activity against dietary Fe levels indicated that the optimal dietary Fe levels are 85.01, 87.53, 87.04, 91.23 mg/kg in Oncorhynchus kisutch post-smolts, respectively.

Evaluation of dietary Fe on juvenile mirror carp (Cyprinus carpio var. specularis) and lettuce (Lactuca sativa var. ramosa Hort) in recirculating aquaponic system

In this study, we assessed the effects of dietary Fe level on the growth performance, nutritional status and health condition of mirror carp (Cyprinus carpio var. specularis) (12.59 ± 1.73 g), production and quality of lettuce (Lactuca sativa var. ramosa Hort) in recirculating aquaponic system for a 60-day feeding trial. Five semi-purified diets with ferrous sulfate as the iron source were used in the feeding trail, which were: T1 (53.81 mg Fe/kg); T2 (118.83 mg Fe/kg); T3 (209.24 mg Fe/kg); T4 (328.44 mg Fe/kg); T5 (498.74 mg Fe/kg). The findings indicated the following: (1) The growth results showed that compare to other groups, the weight gain of mirror carp in Group T2 was the highest, and the feed conversion ratio was the lowest (P < 0.05). (2) The body composition results showed that muscle crude fat and crude protein of the mirror carp significantly increase in the T2 group compared to the T1 group (P < 0.05). Additionally, the C20:5n-3 levels in both the T2 and T3 groups were significantly higher than that of T1 group (P < 0.05). (3) Group T2 exhibited the highest liver superoxide dismutase activity, with significantly elevated catalase activity compared to the other groups (P < 0.05), and the liver malondialdehyde content in group T2 was significantly lower than the T4 and T5 groups (P < 0.05). (4) The morphological measurements of intestinal tissues in mirror carp showed that compared to Group T1 and Group T5, Group T2 exhibited the highest villus length and muscular layer thickness (P < 0.05). (5) The lowest yield of lettuce is in the T1group (3.35 kg/m2/month), and the highest yield (3.96 kg/m2/month) is in the T5 group, along with the highest chlorophyll and soluble sugar content (P < 0.05). (6) The T5 group had the highest nitrogen utilization efficiency (69.44%), while the T1 group had the lowest nitrogen utilization efficiency (58.37%). In addition, the different dietary iron levels did not adversely affect the water quality of the aquaponic systems. Based on the line regression analysis of weight gain and feed conversion ratio with feed iron content, it was found that the most suitable iron content in feed is 118.22–120.44 mg/kg, and the production and quality of lettuce will increase with the increase of feed iron content. According to the results of fish and vegetable growth, as well as nitrogen utilization efficiency, it is suggested that the dietary iron level in the feed of juvenile mirror carp utilized within aquaponic systems should ideally fall within the range of 120–200 mg/kg.

Comparison of the effects of high dietary iron levels on bone microarchitecture responses in the mouse strains 129/Sv and C57BL/6J

Iron is an essential nutrient for all living organisms. Both iron deficiency and excess can be harmful. Bone, a highly metabolic active organ, is particularly sensitive to fluctuations in iron levels. In this study, we investigated the effects of dietary iron overload on bone homeostasis with a specific focus on two frequently utilized mouse strains: 129/Sv and C57BL/6J. Our findings revealed that after 6 weeks on an iron-rich diet, 129/Sv mice exhibited a decrease in trabecular and cortical bone density in both vertebral and femoral bones, which was linked to reduced bone turnover. In contrast, there was no evidence of bone changes associated with iron overload in age-matched C57BL/6J mice. Interestingly, 129/Sv mice exposed to an iron-rich diet during their prenatal development were protected from iron-induced bone loss, suggesting the presence of potential adaptive mechanisms. Overall, our study underscores the critical role of genetic background in modulating the effects of iron overload on bone health. This should be considered when studying effects of iron on bone.

Effect of feeding different dietary levels of zinc and iron on growth performance immune response and hematological parameters of growing Turkey poults

Effect of feeding different dietary levels of zinc and iron on growth performance immune response and hematological parameters of growing Turkey poults

Iron and cancer: overview of the evidence from population-based studies.

Iron is an essential nutrient required for various physiological processes in the body. However, iron imbalance can potentially contribute to initiating and promoting cancer development. Epidemiological studies have investigated the relationship between dietary iron intake and the risk of different types of cancer, yet, not all studies have consistently shown a significant association between dietary iron and cancer risk. Also, studies have shown different effects of dietary heme and non-heme iron intake on cancer risk. While some epidemiological studies suggest a possible link between high dietary iron (mainly heme-iron) intake and increased cancer risk, the evidence remains inconsistent. Moreover, multiple iron biomarkers, which can mirror physiological iron status, have demonstrated varied correlations with the risk of cancer, contingent upon the specific biomarker analyzed and the type of cancer being investigated. Here, we have investigated the current evidence on the potential relationship between dietary iron intake on one hand, and iron biomarkers on the other hand, with the risk of developing different types of cancer, including breast, prostate, lung, pancreatic, colon, colorectal, and liver cancers. Further research is warranted to better understand the complex relationship between dietary iron, physiological iron and cancer development. Future research should account for factors that affect and interact with dietary iron and physiological iron levels, such as genetic susceptibility, overall diet quality, and lifestyle habits.

Assessment the Levels of Serum Ferritin and Some Biochemical Parameters in Type 2 Diabetic Subjects Attending A Tertiary Hospital in Bangladesh

Background: Type 2 diabetes (NIDDM) is the commonest form of diabetes constituting nearly 90% of the diabetic population in any country. Iron is an important mineral in normal physiological processes, and ferritin is a specialized iron storage protein, which reflects iron stores in the body. Iron overload is a risk factor for diabetes. The link between iron and diabetes was first recognized in pathologic conditions-hereditary hemochromatosis and thalassemia, but high levels of dietary iron also import diabetes risk. Iron plays a direct and causal role in diabetes pathogenesis mediated both by β-cell failure and insulin resistance. The objective of the study to evaluate serum ferritin level among type 2 diabetes patients. Method: A hospital based observational study a total of 240 subjects among them 60 male diabetes patients and 60 female diabetes patients were recruited. Serum ferritin level were checked in all participants. Results: The mean age of T2DM was 59  14 years and control group was 50  13 years. The BMI of each group was 27.52  2.6 and 24.80  2.4. Ferritin (ng/dL) level in T2 DM subjects was 231  36 and control subjects was 48  22. Serum ferritin level among the study subjects control vs T2 DM, t/p value (8.465/0.0001). Conclusion: From this study it was observed that ferritin level is significantly higher among type 2 diabetes patients.

Effect of dietary iron (Fe) level on growth performance and health status of largemouth bass (Micropterus salmoides)

The aim of this study was to investigate the effects of dietary iron (Fe) levels on the growth performance, health status, meat quality, and intestinal flora of juvenile largemouth bass (Micropterus salmoides) and to determine the dietary Fe requirement of largemouth bass. Largemouth bass was fed with 6 isonitrogenous and isocaloric experimental diets containing Fe levels of 42.26, 50.79, 66.61, 80.86, 123.13, and 201.87 mg/kg for 10 weeks. The results showed that both final body weight (FBW) and specific growth rate (SGR) tended to increase and then decrease with increasing dietary Fe level, reaching their highest values of 50.34 g and 3.58%/d at a dietary Fe concentration of 80.86 mg/kg respectively. Feed efficiency (FE) and protein efficiency ratio (PER) increased linearly with increasing dietary Fe level. Total serum protein (TP) and urea nitrogen (UN) decreased linearly with increasing dietary Fe level. Serum superoxide dismutase (SOD) and catalase (CAT) enzyme activities tended to increase and then decrease with increasing dietary Fe level, while serum malondialdehyde (MDA) level tended to decline and then increase. In addition, increased dietary Fe level tended to improve muscle hardness and chewiness, thus improving meat quality. Analysis of the intestinal flora showed that the abundance of microorganisms such as Plesiomonas, Peptostreptococcaceae, and Lactococcus in the genus level increased significantly at dietary Fe concentrations of 80.86 mg/kg and 201.87 mg/kg, indicating that appropriate levels of dietary Fe can increase the diversity of intestinal microorganisms. Optimal dietary Fe levels for juvenile largemouth bass were determined to be between 73.81 and 83.22 mg/kg based on the broken-line regression analyses of SGR, FE, or hemoglobin content.

Could commercial meal kits be part of the solution to food insecurity during pregnancy? An Australian exploratory study.

To explore the nutritional content of meal kits from two main Australian companies over a 6-week period against healthy eating guidelines for pregnancy. Across the 6-week period, weekly meal kits from both Provider 1 and Provider 2 were purchased, 36 individual meals were assessed. All data were analysed for the development of a macronutrient and micronutrient profile of meals. Extracted data were macronutrient, vitamin, and mineral composition, which were compared against the healthy eating guidelines for pregnant women in Australia and New Zealand. Meal kits include higher levels of sodium, and lower levels of dietary fibre, calcium, magnesium, zinc, iron, thiamin, riboflavin, grains, and dairy when compared against the guidelines for healthy eating for pregnant women in Australia and New Zealand. Meal kits may increase meals prepared and consumed in the home, and thanks to the clear instructions and pre-portioned ingredients, may reduce stress related to food preparation. They have the potential to provide nutritionally adequate meals to pregnant women as a way to mitigate food insecurity or hunger during pregnancy and may provide some nutritional benefits and have the potential to remove some of the challenges with maintaining an adequate diet when pregnant.

A perspective on addressing rancidity in pearl millet

Pearl millet is a boon crop having the inherent capacity to grow under adverse environmental conditions without compromising with the quality and quantity of the grains. Among millets, pearl millet has many health benefits and new variants that are being conventionally cultivated provides a higher level of dietary iron to women. However, off-odour development in flour is one of the major limiting factors in the popularization of pearl millet all over the world. The poor keeping quality of pearl millet flour is due to the oxidative/ hydrolytic rancidity caused by enzymes like lipase and lipoxygenase that hydrolyse triacylglycerol to free fatty acids and lead to rapid deterioration of flour during storage. In this review, the changes observed in nutritional value of pearl millet flour during storage and key biochemical parameters associated with the development of flour rancidity and the genetics controlling rancidity associated traits are discussed

Dietary Iron Levels and Hypoxia Independently affect Iron Absorption in Mice

The effect of dietary iron levels on the hypoxic response of iron absorption was investigated by feeding mice diets of different iron composition and determining iron absorption. Eight groups of mice were fed a purified diet consisting of casein, corn oil and sucrose with vitamins and iron-free mineral supplements. Groups A–D were fed a nonpurified diet until 6 wk old and then switched to purified diet for 4 d. Groups E–H were fed purified diet for 4 wk from weaning. Groups C, D, G and H were exposed to hypoxia (53.3 kPa) for the last 3 d of the study. Groups A, C, E and G received the low iron purified diet (<1 mg iron per kg); the other groups received the same diet supplemented with 62 mg/kg iron as FeCl3·6H2O. Hypoxic exposure raised iron absorption (P < 0.001) by a similar proportion (2.5- to 5.0-fold) in all mice but did not affect duodenal nonheme iron levels. Low iron diet feeding raised iron absorption but reduced duodenal and liver nonheme iron levels. In a second experiment, mice fed nonpurified diet were divided into four groups and exposed to normal atmosphere or hypoxia (53.3 kPa) with or without dosing with 100 µg iron by stomach tube 1 h before determining iron absorption. There was no effect of iron dosing on iron absorption at either pressure. The data suggest that the control of iron absorption by tissue oxygen acts through a mechanism independent of the control exerted by dietary or mucosal iron levels.

Dietary Intake Levels of Iron, Copper, Zinc, and Manganese in Relation to Cognitive Function: A Cross-Sectional Study.

Background: Previous studies have related circulating levels of trace metal elements, of which dietary intake is the major source, to cognitive outcomes. However, there are still relatively few studies evaluating the associations of dietary intake levels of iron, copper, zinc, and manganese with cognitive function (CF). Methods: We leveraged the data of 6863 participants (mean [standard deviation] age = 66.7 [10.5] years) in the Health and Retirement Study (2013/2014). Dietary intake levels of iron, copper, zinc, and manganese were calculated from a semi-quantitative food frequency questionnaire. CF was assessed using the 27-point modified Telephone Interview for Cognitive Status (TICS). We used linear regression models to calculate the mean differences in global CF scores by quintiles of dietary intake levels of trace metal elements. Results: Among the study participants, the mean (SD) values of daily dietary intake were 13.3 (6.3) mg for iron, 1.4 (0.7) mg for copper, 10.7 (4.6) mg for zinc, and 3.3 (1.6) mg for manganese. Compared with the lowest quintile of dietary iron intake (<8.1 mg), the highest quintile (≥17.7 mg) was associated with a lower cognitive score (-0.50, -0.94 to -0.06, P-trend = 0.007). Higher dietary copper was significantly associated with poorer CF (P-trend = 0.002), and the mean difference in cognitive score between extreme quintiles (≥1.8 vs. <0.8 mg) was -0.52 (95% confidence interval: -0.94 to -0.10) points. We did not observe significant associations for dietary intake of zinc (P-trend = 0.785) and manganese (P-trend = 0.368). Conclusion: In this cross-sectional study, higher dietary intake of iron and copper was related to worse CF, but zinc and manganese intake levels were not significantly associated with CF.

Effects of Dietary Supplementation with Iron in Breeding Pigeons on the Blood Iron Status, Tissue Iron Content, and Full Expression of Iron-Containing Enzymes of Squabs.

This study was aimed at investigating the effects of diet iron levels on the blood iron status, tissue iron content, mRNA levels, and the activity of iron-containing enzymes in different tissues of squabs. A total of 120 pairs of healthy Silver Feather King parental pigeons with similar average body weight and egg production were randomly divided into 5 groups with 8 replicates and 3 pairs of pigeons per replicate. The five groups of breeding pigeons were fed an iron-unsupplemented basal diet and basal diet supplemented with 75, 150, 300, and 600mg iron/kg, respectively. The diets were fed in the form of granular feed based on corn, soybean meal, wheat, and sorghum. A broken line model was used for regression analysis. The results showed that plasma iron (PI), serum ferritin, iron contents in crop milk and liver, liver catalase (CAT) activity, and heart succinate dehydrogenase (SDH) activity were affected by iron levels (P < 0.05). And PI, serum ferritin, iron content in crop milk, and heart SDH activity increased quadratically (P < 0.05), but the iron content and CAT activity in the liver decreased quadratically (P < 0.005) as dietary iron level increased. According to the broken-line model of serum ferritin fitting (P < 0.002), the optimal dietary iron level of breeding pigeons was estimated to be 193mg/kg. In conclusion, serum ferritin is a sensitive index to evaluate the iron requirement of the breeding pigeon with two squabs, and the recommended iron supplemental level is 193mg/kg.

Effects of dietary iron levels on growth performance, iron metabolism and antioxidant status in spotted seabass (Lateolabrax maculatus) reared at two temperatures

The increased ambient temperature is often accompanied by the enhanced metabolic rate and oxygen consumption of fish, which affects their nutritional requirements. Currently, no information compares the iron requirements of fish species under moderate and high temperatures. This study investigated the effects of dietary iron levels on growth performance, iron metabolism, and antioxidant status in spotted seabass (Lateolabrax maculatus) reared at two temperatures. Six diets were formulated to contain 63, 120, 188, 316, 425, and 554 mg/kg iron, each of which was fed to two groups of juveniles reared at 27°C (MT) and 33°C (HT) for 56 days. The results showed that the satisfied iron requirement for spotted seabass improved growth, feed utilization, and antioxidant capacity. Furthermore, fish fed with high‑iron diets prevented iron overload by repressing intestinal iron-regulatory proteins and inducing liver hepcidin production. Iron deficiency depressed erythropoiesis and worsened HT-induced hypoxic status. Moreover, the HT compromised fish growth, feed utilization and liver hepcidin expression, while inducing lipid deposition. Compared to 27°C, the iron demand of spotted seabass was increased at 33°C as more blood erythrocyte and tissue iron deposition were required. Based on the broken-line regression analysis of weight gain, the optimum dietary iron levels for spotted seabass reared at 27°C and 33°C were 178.5 and 209.0 mg/kg, respectively.

Social interaction and geographic diffusion of iron‐biofortified beans in Rwanda

AbstractThis study analyzes smallholder farmers’ decisions to adopt beans with higher levels of dietary iron developed through a conventional breeding technique called biofortification. We approach this study by applying spatial econometric techniques to estimate neighborhood influence and to determine the factors driving the adoption of iron‐biofortified beans (IBB). We employ a cross‐sectional, nationally representative survey of bean producing households from 2015 bean growing season B in Rwanda, and present results for growers of both bush and climbing varieties of beans. The results show geographic diffusion of iron bean planting material occurs among neighboring farmers that exhibit interdependent decision‐making patterns, as well as similar characteristics relative to the group. Some policy implications can be drawn from the results. First, a differentiated geographical targeting strategy for bush and climbing bean varieties as a function of farmer and farm characteristics should increase iron bean adoption rates. Second, strengthening partnerships with delivery agents and extensionists should stimulate the adoption of IBB varieties. And finally, technology‐promotion programs that consider progressive farmers and strengthen social interactions and group activities among peer networks should increase the spread of information and diffusion of IBB.

Gene losses in the common vampire bat illuminate molecular adaptations to blood feeding.

Vampire bats are the only mammals that feed exclusively on blood. To uncover genomic changes associated with this dietary adaptation, we generated a haplotype-resolved genome of the common vampire bat and screened 27 bat species for genes that were specifically lost in the vampire bat lineage. We found previously unknown gene losses that relate to reduced insulin secretion (FFAR1 and SLC30A8), limited glycogen stores (PPP1R3E), and a unique gastric physiology (CTSE). Other gene losses likely reflect the biased nutrient composition (ERN2 and CTRL) and distinct pathogen diversity of blood (RNASE7) and predict the complete lack of cone-based vision in these strictly nocturnal bats (PDE6H and PDE6C). Notably, REP15 loss likely helped vampire bats adapt to high dietary iron levels by enhancing iron excretion, and the loss of CYP39A1 could have contributed to their exceptional cognitive abilities. These findings enhance our understanding of vampire bat biology and the genomic underpinnings of adaptations to blood feeding.

Evaluation of the optimum dietary iron level and its immunomodulatory effects on juvenile Chinese mitten crab, Eriocheir sinensis

This study evaluated the effects of dietary iron levels on growth, antioxidant status and non-specific immunity in juvenile Chinese mitten crab (Eriocheir sinensis). A 56-day feeding trial containing six experimental diets supplemented with six iron levels (0, 30, 60, 120, 240, 480 mg/kg) was conducted. The crabs fed the 177 mg/kg iron diet had significantly higher weight gain and specific growth rate and lower feed conversion ratio compared with those fed the 64 and 508 mg/kg iron diets. A positive correlation was observed between the iron content in the whole body and hepatopancreas with dietary iron supplementation. The catalase activities, total antioxidant capacity, superoxide dismutase and glutathione peroxidase in the hepatopancreas were significantly increased in 89–177 mg/kg iron diets. In addition, the non-specific immunity of the crabs was also improved with the increasing level of dietary iron supplementation (P < 0.05). Broken-line analysis on weight gain, specific growth rate and iron level in the hemolymph against dietary iron levels indicates that the optimal iron requirement for juvenile crabs ranged from 130 to 141 mg/kg. The transcription of iron regulatory protein had a decreasing trend while that of ferritin-1and ferritin-2 had an increasing trend regardless of the lipopolysaccharide and phosphate buffer saline treatment. The highest transcription of inflammation-related genes in the hepatopancreas was found in the crabs fed diets without iron supplementation under the lipopolysaccharide stimulation. Our results indicate that the optimal iron requirement for juvenile crabs was in the range of 130–141 mg/kg and dietary iron plays an indispensable role in the innate immune system in E. sinensis.

Dietary iron (Fe) requirement of coho salmon ( Oncorhynchus kisutch ) alevins assessed using growth, whole body and hepatic Fe concentrations and hepatic antioxidant enzymes activities

In this study, the effects of different dietary iron levels on the growth performance, body composition and antioxidant responses were investigated in the coho salmon Oncorhynchus kisutch alevins. Six experimental diets were formulated to contain graded levels (23.7, 46.4, 59.8, 77.3, 101.7 and 127.7 mg/kg) of iron provided as FeSO4∙7H2O. Each diet was fed to triplicate groups of coho salmon alevins with initial mean weight of 0.35 ± 0.02 g in a flow-through rearing system for 84 days. The results showed that there was no significant difference in survival among dietary treatments. Specific growth rate (SGR) increased significantly (p < 0.05) while feed conversion rate (FCR) decreased significantly (p < 0.05) with increasing dietary iron level from 23.7 up to 101.7 mg/kg. Whole body moisture and ash showed no significant differences among dietary treatments. Fish fed the diet with 127.7 mg/kg had the significantly highest whole body protein and lipid levels (p < 0.05). Whole body and hepatic iron concentrations increased with increasing dietary iron levels (p < 0.05). However, hepatic iron concentrations were decreased when the dietary iron was higher than 77.3 mg/kg treatment. Fish fed the diet with 77.3 mg/kg had the significantly highest activities of catalase (CAT) and total superoxide dismutase (T-SOD) but the lowest malondialdehyde (MDA) activity in liver (p < 0.05). Based on the SGR, iron concentrations in the whole body and liver and CAT, T-SOD and MDA activities in liver, the optimal dietary iron requirements for coho salmon alevins were 101.7, 79.3, 75.7, 90.8, 83.6 and 68.9 mg/kg respectively.

Dietary Iron Intake in Excess of Requirements Impairs Intestinal Copper Absorption in Sprague‐Dawley Rat Dams, Causing Copper Deficiency in Neonatal Pups

Consumption of a high-iron diet by previously iron-deficient rat dams causes copper insufficiency; however, pathophysiological outcomes in their offspring are unknown. We hypothesized that high-iron consumption by dams would also lead to copper depletion in suckling pups. Accordingly, 8-9-week-old, pregnant Sprague-Dawley rats were randomized and initially fed a low-Fe diet for ≍7 days (to induce iron deficiency), and then switched to one of five AIN-93G-based diets, with variable iron levels (normal [80 ppm] to high [up to 1600 ppm]) and marginal copper content (2 ppm; normal is 6-7 ppm). Dams were fed these diets throughout the remainder of pregnancy and during lactation, until the termination of the experiments (when suckling pups were 13-15 days of age). Subsequently, hematological parameters and serum and tissue iron concentrations were measured, and copper biomarker analyses were performed. Intestinal 64Cu absorption and tissue distribution in dams, and 64Cu delivery to the suckling pups, were also assessed. Results showed that serum para-phenylenediamine (pPD) oxidase activity (reflecting serum ceruloplasmin [Cp]) was suppressed (p<0.05) in dams consuming 5-fold excess iron and in pups suckling dams that consumed iron at 10-fold excess. Hepatic nonheme iron concentrations increased in dams and pups (p<0.05) as dietary iron levels increased (possibly due to inhibition of Cp activity, which is required for iron release from hepatocytes). When dams consumed iron at 20-fold above requirements, pup growth was impaired (p<0.05), possibly due to copper depletion, as also indicated by decreases in erythrocyte SOD activity (which accurately reflects copper status) (p<0.05). Moreover, in iron-supplemented dams, intestinal copper (64Cu) absorption and 64Cu activity in blood, liver, and spleen were all decreased (p<0.05). A similar trend was also noted in pups suckling dams consuming exces iron, with 64Cu accumulation in blood, liver, and spleen (p<0.05) being lower than in controls. We conclude that maternal intake of excessive iron (~10-fold above the dietary recommendation) impairs absorption of dietary copper and concomitantly depletes copper in neonatal pups. Low milk copper content was the most likely explanation for this outcome, although this remains to be experimentally proven.