Treatments for Iron Deficiency (ID): Prospective Organic Iron Fortification

Effect of replacing inorganic iron with iron-rich microbial preparations on growth performance, serum parameters and iron metabolism of weaned piglets

This study aimed to investigate the effects of replacing of dietary inorganic iron with iron-rich Lactobacillus plantarum and iron-rich Candida utilis on the growth performance, serum parameters, immune function and iron metabolism of weaned piglets. Fifty-four 28-day-old healthy Duroc × Landrace × Yorkshire castrated male weanling piglets of similar body weight were randomly and equally divided into three groups. The piglets were kept in three pens per group, with six pigs in each pen. The dietary treatments were (1) a basal diet + ferrous sulfate preparation containing 120 mg/kg iron (CON); (2) a basal diet + iron-rich Candida utilis preparation containing 120 mg/kg iron (CUI); and (3) a basal diet + iron-rich Lactobacillus plantarum preparation containing 120 mg/kg iron (LPI). The entire feeding trial lasted for 28 days, after which blood, viscera, and intestinal mucosa were collected. The results showed no significant difference in growth parameters and organ indices of the heart, liver, spleen, lung, and kidney of weaned piglets when treated with CUI and LPI compared with the CON group (P > 0.05). However, CUI and LPI significantly reduced the serum contents of AST, ALP, and LDH (P < 0.05). Serum ALT content was significantly lower in the LPI treatment compared to the CON group (P < 0.05). Compared to CON, CUI significantly increased the contents of serum IgG and IL-4 (P < 0.05), and CUI significantly decreased the content of IL-2. LPI significantly increased the contents of serum IgA, IgG, IgM and IL-4 (P < 0.05), while LPI significant decreased the levels of IL-1β, IL-2, IL-6, IL-8, and TNF-α compared to CON (P < 0.05). CUI led to a significant increase in ceruloplasmin activity and TIBC (P < 0.05). LPI significantly increased the contents of serum Fe and ferritin, and increased the serum ceruloplasmin activity and TIBC compared to CON (P < 0.05). Furthermore, CUI resulted in a significant increase in the relative mRNA expression of FPN1 and DMT1 in the jejunal mucosa (P < 0.05). LPI significantly increased the relative mRNA expression of TF, FPN1, and DMT1 in the jejunal mucosa (P < 0.05). Based on these results, the replacement of dietary inorganic iron with an iron-rich microbial supplement could improve immune function, iron absorption and storage in piglets.

Effects of iron deficiency and iron supplementation at the host-microbiota interface: Could a piglet model unravel complexities of the underlying mechanisms?

Iron deficiency is the most prevalent human micronutrient deficiency, disrupting the physiological development of millions of infants and children. Oral iron supplementation is used to address iron-deficiency anemia and reduce associated stunting but can promote infection risk since restriction of iron availability serves as an innate immune mechanism against invading pathogens. Raised iron availability is associated with an increase in enteric pathogens, especially Enterobacteriaceae species, accompanied by reductions in beneficial bacteria such as Bifidobacteria and lactobacilli and may skew the pattern of gut microbiota development. Since the gut microbiota is the primary driver of immune development, deviations from normal patterns of bacterial succession in early life can have long-term implications for immune functionality. There is a paucity of knowledge regarding how both iron deficiency and luminal iron availability affect gut microbiota development, or the subsequent impact on immunity, which are likely to be contributors to the increased risk of infection. Piglets are naturally iron deficient. This is largely due to their low iron endowments at birth (primarily due to large litter sizes), and their rapid growth combined with the low iron levels in sow milk. Thus, piglets consistently become iron deficient within days of birth which rapidly progresses to anemia in the absence of iron supplementation. Moreover, like humans, pigs are omnivorous and share many characteristics of human gut physiology, microbiota and immunity. In addition, their precocial nature permits early maternal separation, individual housing, and tight control of nutritional intake. Here, we highlight the advantages of piglets as valuable and highly relevant models for human infants in promoting understanding of how early iron status impacts physiological development. We also indicate how piglets offer potential to unravel the complexities of microbiota-immune responses during iron deficiency and in response to iron supplementation, and the link between these and increased risk of infectious disease.

Ferrous Bisglycinate Supplementation Modulates Intestinal Antioxidant Capacity via the AMPK/FOXO Pathway and Reconstitutes Gut Microbiota and Bile Acid Profiles in Pigs

Multi-omics were applied to compare the risks and benefits of ferrous sulfate (FeSO₄) and ferrous bisglycinate (FebisGly) in pigs in the current study. The FebisGly group showed reduced triglyceride (TG) and triglyceride/total cholesterol (TG/CHOL) values in the serum and reduced malondialdehyde (MDA) and increased glutathione (GSH) levels in the duodenum. Transcriptome analysis revealed that differentially expressed genes in the duodenum were enriched in oxidative phosphorylation, AMPK, and FOXO signaling pathways between FeSO₄ and FebisGly groups. AMPK phosphorylation and FOXO3 protein expressions were significantly increased in the FebisGly group. Bacterial 16S rRNA gene sequence analysis revealed significantly reduced alpha diversity in the FeSO₄ group and increased Firmicutes, reduced Bacteroidetes, and Proteobacteria abundances in the FebisGly group. Targeted metabolome revealed notably increased lithocholic acid (LCA), glycolithocholic acid (GLCA), hyodeoxycholic acid (HDCA), ursodeoxycholic acid (UDCA), and glycoursodeoxycholic acid (GUDCA) in the FebisGly group. RDA analysis indicated that Fusobacteria was positively correlated with TG and TG/high-density lipoprotein in the FeSO₄ group while Christensenellaceae_R-7_group, Ruminococcaceae_UCG-002, and Ruminococcaceae_UCG-005 were positively correlated with UDCA and GLCA in the FebisGly group. According to the current study, FebisGly improves serum lipid metabolism, modulates intestinal antioxidant capacity via the AMPK/FOXO pathway, and reconstitutes gut microbiota and bile acid profiles in pigs.

Dietary Supplementation of Ferrous Glycine Chelate Improves Growth Performance of Piglets by Enhancing Serum Immune Antioxidant Properties, Modulating Microbial Structure and Its Metabolic Function in the Early Stage

The present research aimed to explore the effect of dietary ferrous glycine chelate supplementation on performance, serum immune-antioxidant parameters, fecal volatile fatty acids, and microbiota in weaned piglets. A total of 80 healthy piglets (weaned at 28 day with an initial weight of 7.43 ± 1.51 kg) were separated into two treatments with five replicates of eight pigs each following a completely randomized block design. The diet was a corn-soybean basal diet with 2,000 mg/kg ferrous glycine chelates (FGC) or not (Ctrl). The serum and fecal samples were collected on days 14 and 28 of the experiment. The results indicated that dietary FGC supplementation improved (p < 0.05) the average daily gain and average daily feed intake overall, alleviated (p < 0.05) the diarrhea rate of piglets at the early stage, enhanced (p < 0.05) the levels of superoxide dismutase and catalase on day 14 and lowered (p < 0.05) the MDA level overall. Similarly, the levels of growth hormone and serum iron were increased (p < 0.05) in the FGC group. Moreover, dietary FGC supplementation was capable of modulating the microbial community structure of piglets in the early period, increasing (p < 0.05) the abundance of short-chain fatty acid-producing bacteria Tezzerella, decreasing (p < 0.05) the abundance of potentially pathogenic bacteria Slackia, Olsenella, and Prevotella as well as stimulating (p < 0.05) the propanoate and butanoate metabolisms. Briefly, dietary supplemented FGC ameliorates the performance and alleviated the diarrhea of piglets by enhancing antioxidant properties, improving iron transport, up-regulating the growth hormone, modulating the fecal microbiota, and increasing the metabolism function. Therefore, FGC is effective for early iron supplementation and growth of piglets and may be more effective in neonatal piglets.

Astrocytes in heavy metal neurotoxicity and neurodegeneration

With the industrial development and progressive increase in environmental pollution, the mankind overexposure to heavy metals emerges as a pressing public health issue. Excessive intake of heavy metals, such as arsenic (As), manganese (Mn), mercury (Hg), aluminium (Al), lead (Pb), nickel (Ni), bismuth (Bi), cadmium (Cd), copper (Cu), zinc (Zn), and iron (Fe), is neurotoxic and it promotes neurodegeneration. Astrocytes are primary homeostatic cells in the central nervous system. They protect neurons against all types of insults, in particular by accumulating heavy metals. However, this makes astrocytes the main target for heavy metals neurotoxicity. Intake of heavy metals affects astroglial homeostatic and neuroprotective cascades including glutamate/GABA-glutamine shuttle, antioxidative machinery and energy metabolism. Deficits in these astroglial pathways facilitate or even instigate neurodegeneration. In this review, we provide a concise outlook on heavy metal-induced astrogliopathies and their association with major neurodegenerative disorders. In particular, we focus on astroglial mechanisms of iron-induced neurotoxicity. Iron deposits in the brain are detected in main neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Accumulation of iron in the brain is associated with motor and cognitive impairments and iron-induced histopathological manifestations may be considered as the potential diagnostic biomarker of neurodegenerative diseases. Effective management of heavy metal neurotoxicity can be regarded as a potential strategy to prevent or retard neurodegenerative pathologies.

A Novel Mediation Strategy of DSS-Induced Colitis in Mice Based on an Iron-Enriched Probiotic and In Vivo Bioluminescence Tracing

Iron deficiency (ID) caused by blood loss and/or reduced iron absorption is a serious problem influencing health in inflammatory bowel disease (IBD). However, traditional iron supplements may fail to meet no side effect demands for ID of IBD; thus, a new iron supplementation is highly desired to be developed. Herein, for the first time, probiotic Lactobacillus alimentarius NKU556 with an iron-enriching ability was screened from Chinese traditional fermented food then employed to intervene DSS-induced colitis with bioluminescence tracing in mice. As expected, oral administration with NKU556-Fe can remarkably enhance the expression of tight junction proteins and effectively reduce the pro-inflammatory cytokines as well as the oxidative stress on DSS-induced colitis in mice. Meanwhile, in comparison with the FeSO₄ group, the intake of NKU556-Fe could suppress the expression of hepcidin derived from the liver and reduce the degradation of FPN1, thereby leading to the increase in the iron absorption of colitis in mice. According to the bioluminescence result, it was believed that the beneficial effects of oral administration with NKU556/NKU556-Fe on DSS-induced colitis in mice were hardly related to its metabolites but associated with its own function. These results concluded that the oral administration of NKU556-Fe could relieve colitis inflammation and increase iron absorption. In summary, current work not only proposed a novel mediation strategy for IBD but also offered some inspirations for future treatment of extraintestinal complications.

Regulation of Iron Homeostasis and Related Diseases

The liver is the organ for iron storage and regulation; it senses circulating iron concentrations in the body through the BMP-SMAD pathway and regulates the iron intake from food and erythrocyte recovery into the bloodstream by secreting hepcidin. Under iron deficiency, hypoxia, and hemorrhage, the liver reduces the expression of hepcidin to ensure the erythropoiesis but increases the excretion of hepcidin during infection and inflammation to reduce the usage of iron by pathogens. Excessive iron causes system iron overload; it accumulates in never system and damages neurocyte leading to neurodegenerative diseases such as Parkinson's syndrome. When some gene mutations affect the perception of iron and iron regulation ability in the liver, then they decrease the expression of hepcidin, causing hereditary diseases such as hereditary hemochromatosis. This review summarizes the source and utilization of iron in the body, the liver regulates systemic iron homeostasis by sensing the circulating iron concentration, and the expression of hepcidin regulated by various signaling pathways, thereby understanding the pathogenesis of iron-related diseases.