Effect of dietary selenium intake on gut microbiota in older population in Enshi region

The Immunomodulatory Effects of Selenium: A Journey from the Environment to the Human Immune System

Selenium (Se) is an essential nutrient that has gained attention for its impact on the human immune system. The purpose of this review is to explore Se's immunomodulatory properties and to make up-to-date information available so novel therapeutic applications may emerge. People acquire Se through dietary ingestion, supplementation, or nanoparticle applications. These forms of Se can beneficially modulate the immune system by enhancing antioxidant activity, optimizing the innate immune response, improving the adaptive immune response, and promoting healthy gut microbiota. Because of these many actions, Se supplementation can help prevent and treat pathogenic diseases, autoimmune diseases, and cancers. This review will discuss Se as a key micronutrient with versatile applications that supports disease management due to its beneficial immunomodulatory effects. Further research is warranted to determine safe dosing guidelines to avoid toxicity and refine the application of Se in medical treatments.

Prevotella copri Improves Selenium Deposition and Meat Quality in the longissimus dorsi Muscle of Fattening Pigs

Selenium is among the important trace elements that influence the quality of meat. Although it has been established that the gut microbiota is closely associated with selenium metabolism, it has yet to be determined whether these microbes influence the accumulation of selenium in muscles. To identify gut microbiota that potentially influence the deposition of selenium in muscles, we compared the colonic microbial composition of pigs characterized by high and low contents of selenium in the longissimus dorsi muscle and accordingly detected a higher abundance of the bacterium Prevotella copri (P. copri) in pigs with a higher muscle selenium content. To verify the effect of P. copri, 16 pigs weighing approximately 61 kg were fed either a basal diet or a basal diet supplemented with P. copri (1.0 × 1010 CFU/kg feed) for 45 days. The results revealed significant increases in the contents of selenium and selenoprotein in the serum and longissimus dorsi muscle of fattening pigs fed the P. copri-supplemented diet. Moreover, supplementing the feed of pigs with P. copri was observed to promote significant improvement in the antioxidant capacity and quality of meat, including drip loss, pH, and meat color. In conclusion, our findings in this study indicate that P. copri has potential utility as a dietary supplement for improving the selenium status and meat quality in fattening pigs.

The role of selenium intervention in gut microbiota homeostasis and gene function in mice with breast cancer on a high-fat diet

Objective

This study aimed to investigate the effect of selenium on gut microbiota in mice with breast cancer under a high-fat diet.

Methods

A total of 12 female BALB/c mice were randomly divided into two groups: 4 T1 + selenium+ high-fat diet group and 4 T1 + high-fat diet group. Mice were injected with 4 T1 cells on the right 4th mammary fat pad and kept on a high-fat diet. Fecal samples were collected, and DNA was extracted for metagenomic sequencing and bioinformatics analysis. Relevant target genes and pathways were annotated and metabolically analyzed to explore the intervention effect of selenium on breast cancer in the high-fat diet state.

Results

Selenium supplementation in the high-fat diet altered the composition and diversity of gut microbiota in mice with breast cancer. The gut microbial composition was significantly different in the selenium intervention group, with an increased abundance of Proteobacteria, Actinobacteria, and Verrucomicrobia phyla and species such as Helicobacter ganmani, Helicobacter japonicus, and Akkermansia muciniphila, while phyla, such as Bacteroidetes, Firmicutes, Deferribacteres, and Spirochaetes, and species, such as Prevotella sp. MGM2, Muribaculum intestinale, Lactobacillus murinus, and Prevotella sp. MGM1, were decreased. Functional analysis revealed differential expression of genes related to carbohydrate-active enzymes, pathogen-host interactions, cell communication, cell auto-induction, membrane transporters, and virulence factors. Furthermore, 37 COGs and 48 metabolites with rising metabolic potential in the selenium intervention group were predicted.

Conclusion

Selenium alters the homeostasis of gut microbiota in mice with breast cancer on a high-fat diet, affecting their composition, abundance, and associated metabolism. These findings suggest that the mechanism involves interfering with gut microbiota homeostasis, leading to altered synthesis of tumor-associated proteins and fatty acids and inducing tumor cell apoptosis and pyroptosis.

Effects of nano-selenium on cecum microbial community and metabolomics in chickens challenged with Ochratoxin A

Introduction

Ochratoxin A (OTA) is a widely distributed mycotoxin. Nano-selenium (Nano-Se) is an emerging form of selenium known for its superior bioavailability, remarkable catalytic efficiency, and robust adsorbing capacity. Despite these characteristics, its impact on the microbial community and metabolomics in the cecum of chickens exposed to OTA has been infrequently investigated. This research examined the microbiota and metabolomic alterations linked to OTA in chickens, with or without Nano-Se present.

Methods

A cohort of 80 healthy chickens at the age of 1 day was randomly distributed into four groups of equal numbers, namely the Se cohort (1 mg/kg Nano-Se), the OTA cohort (50 μg/kg OTA), the OTA-Se cohort (50 μg/kg OTA + 1 mg/kg Nano-Se), and the control group. Each chicken group's caecal microbiome and metabolome were characterized using 16S rRNA sequencing and Liquid chromatography coupled with mass spectrometry (LC-MS) analyses.

Results and discussion

Our results showed that the on day 21, the final body weight was significantly reduced in response to OTA treatments (p < 0.05), the average daily gain in the OTA group was found to be inferior to the other groups (p < 0.01). In addition, Nano-Se supplementation could reduce the jejunum and liver pathological injuries caused by OTA exposure. The 16S rRNA sequencing suggest that Nano-Se supplementation in OTA-exposed chickens mitigated gut microbiota imbalances by promoting beneficial microbiota and suppressing detrimental bacteria. Moreover, untargeted metabolomics revealed a significant difference in caecal metabolites by Nano-Se pretreatment. Collectively, the dataset outcomes highlighted that Nano-Se augmentation regulates intestinal microbiota and associated metabolite profiles, thus influencing critical metabolic pathways, and points to a possible food-additive product.

Impact of selenium on the intestinal microbiome-eCBome axis in the context of diet-related metabolic health in mice

Dietary micronutrients act at the intestinal level, thereby influencing microbial communities, the host endocannabinoidome, and immune and anti-oxidative response. Selenium (Se) is a trace element with several health benefits. Indeed, Se plays an important role in the regulation of enzymes with antioxidative and anti-inflammatory activity as well as indicators of the level of oxidative stress, which, together with chronic low-grade inflammation, is associated to obesity. To understand how Se variations affect diet-related metabolic health, we fed female and male mice for 28 days with Se-depleted or Se-enriched diets combined with low- and high-fat/sucrose diets. We quantified the plasma and intestinal endocannabinoidome, profiled the gut microbiota, and measured intestinal gene expression related to the immune and the antioxidant responses in the intestinal microenvironment. Overall, we show that intestinal segment-specific microbiota alterations occur following high-fat or low-fat diets enriched or depleted in Se, concomitantly with modifications of circulating endocannabinoidome mediators and changes in cytokine and antioxidant enzyme expression. Specifically, Se enrichment was associated with increased circulating plasma levels of 2-docosahexaenoyl-glycerol (2-DHG), a mediator with putative beneficial actions on metabolism and inflammation. Others eCBome mediators also responded to the diets. Concomitantly, changes in gut microbiota were observed in Se-enriched diets following a high-fat diet, including an increase in the relative abundance of Peptostreptococcaceae and Lactobacillaceae. With respect to the intestinal immune response and anti-oxidative gene expression, we observed a decrease in the expression of proinflammatory genes Il1β and Tnfα in high-fat Se-enriched diets in caecum, while in ileum an increase in the expression levels of the antioxidant gene Gpx4 was observed following Se depletion. The sex of the animal influenced the response to the diet of both the gut microbiota and endocannabinoid mediators. These results identify Se as a regulator of the gut microbiome and endocannabinoidome in conjunction with high-fat diet, and might be relevant to the development of new nutritional strategies to improve metabolic health and chronic low-grade inflammation associated to metabolic disorders.

Production of Cardamine violifolia selenium-enriched peptide using immobilized Alcalase on Fe3O4 modified by tannic acid and polyethyleneimine

Enzymatic synthesis of selenium (Se)-enriched peptides is vital for their application in supplementing organic Se. However, the poor stability and reusability of the free enzyme impedes the reaction. In this work, a highly stable immobilized Alcalase was synthesized by immobilizing Alcalase on tannic acid (TA) and polyethyleneimine (PEI) modified Fe3O4 nanoparticles (NPs). The optimal immobilization conditions for immobilized Alcalase were found at a TA/PEI (v/v) ratio of 1 : 1, pH of 10, and temperature of 40 °C, and the results from scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) characterization confirmed the successful immobilization of Alcalase. The results of an enzyme property test showed that immobilized Alcalase had higher thermal and pH stability than free Alcalase, and retained 61.0% of the initial enzyme activity after 10 repetitions. Furthermore, the organic Se content of Se-enriched peptide prepared through enzymatic hydrolysis of Cardamine violifolia (CV) protein with immobilized Alcalase was 2914 mg kg-1, and the molecular weight was mainly concentrated in 924.4 Da with complete amino acid components. Therefore, this study proposes the feasibility of immobilized enzymes for the production of Se-enriched peptides.

Potential role of selenium in alleviating obesity-related iron dyshomeostasis

Obesity is a serious health problem in modern life and increases the risk of many comorbidities including iron dyshomeostasis. In contrast to malnourished anemia, obesity-related iron dyshomeostasis is mainly caused by excessive fat accumulation, inflammation, and disordered gut microbiota. In obesity, iron dyshomeostasis also induces disorders associated with gut microbiota, neurodegenerative injury, oxidative damage, and fat accumulation in the liver. Selenium deficiency is often accompanied by obesity or iron deficiency, and selenium supplementation has been shown to alleviate obesity and overcome iron deficiency. Selenium inhibits fat accumulation and exhibits anti-inflammatory activity. It regulates gut microbiota, prevents neurodegenerative injury, alleviates oxidative damage to the body, and ameliorates hepatic fat accumulation. These effects theoretically meet the requirements for the inhibition of factors underlying obesity-related iron dyshomeostasis. Selenium supplementation may have a potential role in the alleviation of obesity-related iron dyshomeostasis. This review verifies this hypothesis in theory. All the currently reported causes and results of obesity-related iron dyshomeostasis are reviewed comprehensively, together with the effects of selenium. The challenges and strategies of selenium supplementation are also discussed. The findings demonstrate the possibility of selenium-containing drugs or functional foods in alleviating obesity-related iron dyshomeostasis.