Zinc Requirements Research Articles

Evaluating the nutritional availability of vegetarian and vegan diets: a cross-sectional analysis of dietary data for UK children ages 2–12

BackgroundGood health is vital for child development, and a key component is a nutritious diet. Food systems impact health, and are also major contributors to greenhouse gas emissions. Sustainable diets have low environmental impacts and contribute to food and nutrition security. Plant-based diets are considered sustainable and nutritionally adequate for adults, whereas their adequacy for children remains under explored; this study aims to understand this. MethodsWe analysed 3-day weighed food diary data from a convenience sample of 39 children aged 2–12 in the UK, consuming a vegan (13), vegetarian (11) or omnivore (15) diet. Nutrients analysed were: calories, total fat, saturated fat, protein, carbohydrate, fibre, free sugar, vitamin A, C, B12 and D, sodium, iodine, iron, calcium, zinc, and folate. Demographic data collected were age, sex, ethnicity, school and lunch type, postcode, parental education, marital status and household income (self reported). Mean daily intakes were compared with recommended daily intakes for age/sex groups, using ANOVA to determine significant differences. University of Warwick's ethics committee approved this study. FindingsChildren were similar in age, sex, ethnicity, school type, school lunch type, and parental qualification across dietary groups, but differed in household income and parental marital status. With vegan households having a significantly lower incomes to omnivore households, and omnivore families had more married parents than vegetarian families. Significant differences were found across groups for saturated fat, vitamins A, C, B12, D, and folate, including supplements. All groups were below the recommendations for calories, total fat, and vitamin D. Vegan diets exceeded sodium recommendations, while omnivorous diets exceeded free sugar recommendations. Both omnivorous and vegetarian diets exceeded saturated fat recommendations. Without supplements, vegan and vegetarian children failed to meet iodine and zinc requirements and vegetarian children did not meet iron recommendations. InterpretationLimitations include: smaller sample size, the use of a convenience sample; and potential under-reporting of food intake, as no group met recommended calorie levels. This study suggests plant-based diets can meet children's nutrient needs with appropriate supplementation. Planning and awareness of supplementation are essential to prevent potential developmental issues. FundingThis project was completed as part of a PhD project funded by The Leverhulme Trust.

Short-Term Zinc Supplementation Stimulates Visceral Adipose Catabolism and Inflammation in Mice.

Zinc (Zn), a fundamental trace element in human biology, exhibits pivotal roles in sustaining vital physiological processes and regulating metabolic homeostasis. Insufficient zinc intake has been linked to deleterious consequences on growth, reproductive functions, metabolic activities, and immune responses in both humans and animals. Oral zinc supplementation is usually performed to meet zinc requirement. Previous studies have shown that long-term supplementation of zinc in mice impaired AKT signaling and induced adipocyte hypertrophy in visceral adipose tissue. The presented study was conducted to investigate the role and mechanism of short-term zinc supplementation on lipids metabolism. Zinc sulfate was supplemented in the drinking water of C57/BL6J male mice at 30 ppm or 90 ppm for one week. Water consumption, food intake, and body weight were analyzed, adipose tissue and serum profile of metabolites were investigated, and the key genes related to lipid metabolism were analyzed. Short-term zinc supplementation decreased visceral adipose tissue weight and adipocyte size compared to the control group, but no difference was observed in food intake, water consumption, and body weight between the two groups. Further studies revealed that short-term zinc supplementation significantly increased the serum insulin level while decreasing the serum NEFA content. In addition, zinc supplementation increased the expression of Atgl and Hsl in the visceral adipose tissue compared with the control mice. Furthermore, the phosphorylation level of HSL and protein level of PPARg in the epididymal adipose tissue increased by zinc supplementation compared with the control mice. In comparison, the protein level of FASN was down-regulated by short-term zinc supplementation in the epididymal adipose tissue, although the expression of lipogenic genes was not changed. The expression of F4/80 and Tnfa were increased in zinc-supplemented adipose tissue as compared with the control group. Our findings suggest that short-term zinc supplementation might reduce fat deposition by enhancing lipolysis in mice. Future studies could focus on the effect of intermittent zinc supplementation on fat reduction in both animal models and humans.

Effects of ZinT-Mediated Zinc Sequestration on Metallo-β-Lactamase Function in Escherichia coli

β-lactams are the most prescribed antibiotic class, but their clinical utility is threatened by the production of metallo-β-lactamase (MBL) enzymes by resistant bacteria. MBLs such as NDM-1 employ zinc ions as cofactors, allowing them to degrade β-lactams. The zinc chaperone ZinT transports zinc into the cytoplasm for intracellular functions, potentially decreasing the availability of zinc in the periplasm for MBLs. We hypothesize that when zinc is limited, ZinT could impair NDM-1 activity and make bacteria more susceptible to β-lactams. To determine whether ZinT and NDM-1 compete for periplasmic zinc, bacterial growth and NDM-1 activity were tested in zinc-poor M9 minimal media for NDM-1-producing Escherichia coli strains with different levels of zinT expression. In addition to wild-type and ΔzinT knockout strains, a recombinant zinT-containing plasmid was transformed into ΔzinT knockout cells to produce a complementation strain with increased zinT expression. Growth assays were conducted in M9 with various concentrations of the β-lactam antibiotic, meropenem. Under these conditions, the ΔzinT strain grew in significantly higher meropenem concentrations than the other strains tested. NDM-1 activity assays revealed that the ΔzinT strain hydrolyzed meropenem notably faster than wild-type cells, whereas the complementation strain showed almost no hydrolysis. This suggests that the increased ZinT production in the complementation strain effectively sequestered zinc from NDM-1. These differences in meropenem hydrolysis and bacterial growth were absent in zinc-sufficient Cation-Adjusted Mueller-Hinton Broth, providing evidence that ZinT and NDM-1 compete for periplasmic zinc under nutrient deficiency. Overall, our results elucidate the effects of competing zinc requirements under zinc-deficient conditions resembling the host environment during a bacterial infection. In these zinc-deficient environments, ZinT can deprive NDM-1 of zinc, causing impaired enzymatic activity and bacterial survival. By better understanding how MBLs function under physiological conditions, future investigations can more reliably explore countermeasures to the growing threat of antibiotic resistance.

Agronomic biofortification of finger millet for zinc, and its influence on yield and partitioning of zinc, iron, and calcium in the plant

Zinc (Zn) deficiency in humans is the most common, and zinc requirement is catered mainly by cereal food grains which have lower zinc content. Finger millet is one of the staple food crops in Africa and India and has only 25 to 30 µg Zn g−1 of grain. Breeding efforts have improved the grain-Zn content to nearly 40 µg g−1 of grain, which is far below the recommended dietary allowance of 15 mg day−1 adult−1, and such varieties are not suited to all the finger millet cultivation regions. Therefore, the objective of the present studies is to enhance the grain-Zn content of locally adapted varieties through agronomic biofortification, which can be adapted for any variety and region. The easy, promising, and cost-effective approach is the soil or foliar application of zinc to increase the grain-Zn content. Present studies over four years revealed that the foliar application of 0.5% ZnSO4·7H2O solution at flowering and 20 days after flowering (DAF) is apt to increase the grain-Zn significantly to 40 µg g−1 of grain. Whereas the soil application of ZnSO4·7H2O at 12.5 kg ha−1 is appropriate to increase the grain yield to 504 g m−2 from 444 g m−2 in the control. The partitioning of zinc and calcium was higher toward the leaf sheath, leaf lamina, and husk than the other plant parts, whereas iron was toward the root. Therefore, the translocation of zinc from leaves to grain needs to be improved for further increase in grain-zinc of finger millet.

Potential Nutrient Contribution of Community-Based Insects in Children’s Food in Northern Ghana

BackgroundMicronutrient deficiencies are a major problem among children in northern Ghana. Available local foods and existing plant-based dietary patterns among children are insufficient to meet children’s nutrients requirements. Aside enhancing diets with animal source foods, most of which are expensive for rural households, entomophagy, which is culturally accepted, appears to be a great alternative. ObjectivesThis study aimed to 1) document the types of insects commonly consumed and the reasons for or against entomophagy in the study area, 2) document the reasons for adding or not adding insects to household meals, and 3) determine the nutrient contribution of community-based insects in children's food. MethodsBoth qualitative and quantitative research methods were concurrently applied in this exploratory study (N = 392 individuals; 6 focus group discussions) in northern Ghana. ResultsTermites, crickets, grasshoppers, and caterpillars were recognized as the most prevalent edible insects in communities. These insects were largely consumed by children but presently only included in household meals by a few households. Individual, sociocultural, sensory characteristics of insects, climate, and economic aspects were cited as grounds for and against entomophagy. Existing community-based children’s diets were unable to meet the acceptable recommended nutrient intake (RNI; within a given age and gender group, the RNI is the amount of a nutrient ingested daily that would meet the needs of almost all healthy individuals in that group) level of all nutrients under consideration, especially for zinc, vitamin B-12, folate, and fat. Inclusion of community-based edible insects increased the RNI levels for all 11 micronutrients considered and met children’s zinc, vitamin B-12, folate, and fat requirements. ConclusionsCommunity-based insects demonstrate a great potential for meeting micronutrients needs of children in the research setting. Future research is required to improve households’ adoption of community-based insects as part of household meals and to make insects accessible to households.

Nature’s food – the contribution of edible insects to household nutrition and income in Western Kenya

Abstract This study investigates the nutritional contribution of insects to the diets and income of an entomophagous region in western Kenya. We used a random sample of households from two sub-counties in western Kenya and collected quantities harvested, consumed, and sold of three common insects (termites, dung beetles, and grasshoppers). We then estimated the nutritional composition from literature and determined the household nutrient requirements for proteins, vitamin A, iron and zinc to understand the contribution of insects. Insects were found to be a source of protein, vitamin A, iron, and zinc, with average contributions of 2%, 14%, 20% and 4% of the recommended (household) dietary intake of each nutrient, respectively. Households that earned income from insects had 24% higher household income compared to those that did not earn income from insects. The study further examined factors influencing the contribution of insects to diets and found that household size and wealth (measured by land size) have an inverse relationship with insect contribution to diets and income while attaining primary level of education and being a farmer as the main occupation are associated with a higher contribution of insects to diets. For future research, understanding factors influencing entomophagy is vital for promoting sustainable and nutritious food systems that incorporate insects as a viable protein source, particularly in regions where alternative protein sources are limited.

Fish contributions toward nutritional security in Kenya

Human nutrient deficiencies remain prevalent globally and are particularly common in low- and middle-income countries, such as Kenya. Fish holds potential to help address these deficiencies but remains barely incorporated in nutrition policies and strategies, partly due to a lack of supporting evidence. We address this gap by analyzing sixteen years of fisheries production and trade data from marine, freshwater, and aquaculture systems to evaluate fish nutrient supply, assess changes in supply, and determine the contributions the current supply could make to meet the nutritional needs of children under five years in Kenya. Despite an 11% increase, through time, in the total supply of fish, there was a 24% decline in per capita fish consumption due to fishery changes and increased fish demand. Furthermore, a 21% decline in supply of fish from inland freshwater systems resulted in a 25–40% decline in nutrient supply. Based on the current supply of fish, Kenya’s per capita consumption of 2.5 kg/yr is below WHO recommendations of 10.4 kg/yr. However, this supply has the potential to support nearly 13 million Kenyans at this WHO recommendation. If supply was targeted towards vulnerable groups, such as children under five years, it could supply all children in Kenya with one-third of their calcium, selenium, and protein and over 70% of children in Kenya with one-third of their iron, zinc, and omega-3 polyunsaturated fatty acids requirements. Therefore, fish can play an important role in supporting nutritional security in Kenya if strategic interventions involving all relevant sectors are considered, to reduce identified nutrient deficiencies.

Assessing Performance of Contemporary Plant-Based Diets against the UK Dietary Guidelines: Findings from the Feeding the Future (FEED) Study.

Uncertainty remains about the composition of contemporary plant-based diets and whether they provide recommended nutrient intakes. We established Feeding the Future (FEED), an up-to-date online cohort of UK adults following different plant-based diets and diets containing meat and fish. We recruited 6342 participants aged 18-99 [omnivores (1562), flexitarians (1349), pescatarians (568), vegetarians (1292), and vegans (1571)] between February 2022 and December 2023, and measured diet using a food frequency questionnaire and free text. We compared personal characteristics and dietary intakes between diet groups and assessed compliance with dietary guidelines. Most participants met UK dietary recommendations for fruit and vegetables, sodium, and protein, although protein intakes were lowest among vegetarians and vegans. Omnivores did not meet the fibre recommendation and only vegans met the saturated fat recommendation. All diet groups exceeded the free sugars recommendation. Higher proportions of vegetarians and vegans were below the estimated average requirements (EARs) for zinc, iodine, selenium, and, in vegans, vitamins A and B12, whereas calcium intakes were similar across the diet groups. People following plant-based diets showed good compliance with most dietary targets, and their risk for inadequate intakes of certain nutrients might be mitigated by improved dietary choices and/or food fortification.

The Significance of Providing the Optimal Micronutrients to the Preterm Low Birth Weight Infants to Prevent Long-Term Health Consequences

Premature infants have less nutritional storage capacity and an underdeveloped body, which makes them particularly susceptible to malnutrition. Nutrient surplus and deficiency are possibilities when supplemental feeding is unbalanced. However, little is known about what kids should eat once they are discharged from the hospital. Since many bodily processes depend on micronutrients, it's critical to plan supplemental nutrition with an optimum consumption in mind. This written summary describes the requirements for long-chain polyunsaturated fatty acids (LCPUFA), iron, zinc, vitamin D, calcium, and phosphate for premature newborns receiving supplemental feeding. The scientific community is beginning to acknowledge the advantages of giving premature babies iron and vitamin D supplements. But as of right now, there isn't enough information available to make firm recommendations about the addition of calcium, phosphorus, zinc, and LCPUFAs. Nonetheless, the health of premature infants depends on the following micronutrients: Large chain polyunsaturated fats (LCPUFAs) support the development of the retina and brain, while calcium and phosphorus dosages are necessary to prevent metabolic bone disease (MBD) in preterm infants. It is obvious how understanding the variability of the premature population may help adapt nutritional planning in connection to the development rate, comorbidities, and thorough clinical history of the preterm newborn, even while we wait for consensus on these micronutrients.

Dietary zinc requirement of juvenile stinging catfish Heteropneustes fossilis based on growth performance, haematology, and tissue mineral composition

This investigation was done to determine how much zinc (Zn) the stinging catfish, Heteropneustes fossilis, needs in its diet. Five isonitrogenous (34.5% protein) and isolipidic (6.0% lipid) diets were prepared to contain graded levels of Zn (0, 10, 20, 30, and 40 mg kg−1), supplied as zinc sulfate (ZnSO4·7H2O), and referred to as Zn0, Zn10, Zn20, Zn30, and Zn40, respectively. A total of 600 fish (initial body weight: 1.41 ± 0.02 g) were stocked in 15 glass aquaria (40 fish/aquarium), each with 180 L water capacity. For ten weeks, each diet was hand fed to three groups of fish twice daily until they appeared satisfied. The highest weight gain and specific growth rate, and lowest feed conversion ratio were recorded in fish fed with a 30 mg Zn kg−1 diet. Zn contents in bone and muscle linearly increased up to 30 mg kg−1 Zn and then remained stable, while iron (Fe) and copper (Cu) contents in bone and muscle had an inverse pattern with the inclusion level of dietary Zn. Increasing dietary Zn levels up to 30 mg kg−1 was found to improve values of hematological parameters such as red blood cell (RBC), white blood cell (WBC), haemoglobin (Hb), and haematocrit (HCT). These values, however, decreased when the dietary Zn level was further increased. The serum alkaline phosphatase level was the highest in fish fed a diet containing 30 mg kg-1 of Zn. Regression analyses based on weight gain, specific growth rate, and bone and muscle Zn concentrations indicated that the optimum dietary Zn requirement for stinging catfish was in a range of 27.4–36.5 mg kg−1.

Compositional Analysis of Complementary Foods Given by Mothers to Children Aged 6-23 Months in Giginyu Nassarawa Local Government Area, Kano State, Nigeria

Under nutrition among young children is high and poor complementary foods have been implicated. The objective of this study was to investigate compositional analysis of complementary foods given by mothers to children aged 6-23 months in Giginyu Nassarawa Local Government Area, Kano State, Nigeria using appropriate standard methods and compare with a commercial complementary food (control). Energy density was designated low if < 0.8 kcal and contribution of meals to daily requirements (RDA) of protein, calcium and zinc for young children determined. The moisture, protein, ash, energy density, calcium, zinc, and phytate contents of the complementary meals (100g wet basis) ranged from 64.32-83.7%, 0.74-6.29%, 0.04-1.41%, 0.37-1.17 kcal/ml, 0.82-27.00 mg/100g, 0.022-0.277mg/100g and 0.05-1.68%, respectively. The soybean based meal, ‘SB’ was significantly higher (p<0.01) than other meals including the control, in protein, ash, energy, calcium, zinc and phytate contents. All other meals met above 50% of the RDA for protein except CMS1 (33%), SMMG (42.1%), PS (19.7%) and MSMP (32.8%). Except SB and CMS2 that contributed above 20-37% of RDA for calcium and zinc, the rest of the complementary meals were very low in calcium and zinc content.The moisture contents of common complementary meals offered to older infants in Giginyu LGA, Kano State are quite high which affected the energy density of the meals. Except for pap/sugar and custard based meals, the meals had appreciable levels of protein contents. However, there was low calcium and zinc (micronutrients) contents of most of the meals with about 400 mls daily consumption.

Prevalence, variety, and iron and zinc content of commercial infant and toddler foods sold in the United States that contain meat.

Iron and zinc are important nutrients during infancy, particularly for infants exclusively fed human milk at the beginning of complementary feeding (CF) from 6-12 months. The 1st Foods Study examined the ingredients and nutrient contents of commercially-available infant and toddler foods (ITFs) that were sold in the US and contained meat. Company websites (n = 22) were used to create a database of commercial ITFs (n = 165) available for purchase in the US and contained at least one meat (e.g., beef, chicken, pork). Single ingredient and ready-to-serve meals (for ages ≤ 9 months) and ready-to-serve meals (for ages 10+ months) were categorized as infant and toddler products, respectively. For each product, the ingredient list, intended age/stage, serving size (g), energy (kcal), protein (g), iron (mg), and zinc (mg) per serving were recorded from product labels. Nutrient amount/100 g was calculated for each product and medians and inter-quartile ranges were calculated and compared (1) by intended age/stage of the product and (2) according to meat type. In general, toddler products contained more iron than infant products. Within infant products (n = 65), more iron was found in products containing beef relative to products with other meats, which were similar in iron content. Within toddler products (n = 38), more iron was found in products containing seafood, followed by beef, turkey, and pork. Slightly less iron was found in products with chicken. Zinc content was infrequently reported (n = 17 total products). Because many of the products assessed contained low amounts of iron and zinc, meeting the current infant and toddler requirements for iron and zinc during the CF period may be challenging if commercial ITFs containing meat are the primary source of these nutrients.

Effects of Replacing Inorganic with Organic Glycinates Trace Minerals on Growth Performance, Gut Function, and Minerals Loss of Juvenile Nile Tilapia.

This study aimed to investigate the effects of replacing inorganic trace minerals (ITM) with organic trace minerals (OTM) on growth performance, body composition, gut histomorphometry, digestive enzyme activity, apparent digestibility coefficients (ADC), and mineral balance in juvenile Nile tilapia, Oreochromis niloticus. Fish (n = 432; 2.5 ± 0.5 g) were randomly distributed into four groups with four replicates each (27 fish per replicate). A control diet (gross 15.2 MJ gross energy kg-1; 367.3 g crude protein kg-1) was elaborated to meet the dietary requirements of zinc (Zn), manganese (Mn), and copper (Cu) using ITM in the sulfate form (ITM100). From the control diet, three diets were elaborated using OTM to supply 100% (OTM100), 75% (OTM75), and 50% (OTM50) of Zn, Mn, and Cu ITM of the control diet, respectively, supplied in the glycinate form. Fish were hand-fed six times daily for 8 weeks. Growth performance was not changed by dietary treatments. Fish fed on the diet OTM50 showed higher whole-body and vertebrae ash contents and higher whole-body calcium (Ca), Zn, and iron (Fe) retention than those fed on the control diet. The activity of digestive enzymes and the ADC of energy and nutrients, including Zn, Mn, and Cu, were similar in fish fed on diets OTM50 and ITM100. A reduction in Zn (-39.8%), Mn (-11.1%), and Cu (-14.0%) loss was observed in fish fed on the diet OTM50 than in fish fed diet ITM100. The dietary treatments did not affect the gut histomorphometry. In conclusion, the inclusion of OTM in Nile tilapia's diets represents a promising strategy to reduce 50% of ITM sources by utilizing Zn, Mn, and Cu OTM as glycinates without detrimental effects on growth performance, nutrient utilization, and gut function. These results additionally reinforce the environmental benefits of using OTM for precise mineral nutrition in aquaculture.

Iron and zinc biofortification of rice by synergistic expression of OsNAS2 gene with monocot (Pennisetum glaucum) and dicot (Phaseolus vulgaris) ferritins

Iron and zinc deficiencies are the most prevalent cause of global hidden hunger. Rice, being one of the most consumed crops worldwide, is suitable to target for Fe and Zn biofortification. In present study, we generated rice transgenic lines to meet the recommended dietary requirement of iron and zinc through endosperm specific expression of dicot (kidney bean) and monocot (pearl millet) Ferritins along with constitutive expression of rice nicotianamine synthase 2 (OsNAS2) gene. Visualization through perls’ prussian staining and quantification by ICP-MS showed significant improvement in grain iron content in all the transgenic lines. The transgenic lines expressing any of the three selected gene combinations (PvFerrtin-OsNAS2, feedPgFerrtin-OsNAS2 and foodPgFerritin-OsNAS2), showed the potential to surpass the 30% of the estimated average requirement (13 μg/g Fe and 28 μg/g Zn) proposed for rice in HarvestPlus breeding program. Though the expression of PvFerritin along with OsNAS2 gene in IET10364 (indica) variety showed the best result, providing up to 4.2- and 3.5-fold increase in iron (30.56 μg/g) and zinc (60.1 μg/g) content, respectively; in polished grains compared to non-transgenic control. Thus, the lines developed in our study can be used for further breeding purpose to enhance the iron and zinc content in commercial rice varieties.

Zinc Supplementation in Very Low Birth Weight Infants: A Randomized Controlled Trial.

Preterm infants have high zinc (Zn) requirements and are generally believed to be in a negative Zn balance in the early period of life. In this study, we aimed to investigate the effect of high-dose Zn supplementation in very low birth weight (VLBW: infants with birth weight < 1.5 kg) infants on feeding intolerance and development of mortality and/or morbidities including necrotizing enterocolitis (NEC) and late-onset sepsis (LOS). This is a prospective randomized trial. VLBW preterm infants with gestational age of <32 weeks were randomly allocated on the seventh day of life to receive extra amount of supplemental Zn along with the enteral feedings (9 + 3 mg), besides regular low-dose supplementation (3 mg), from enrollment until discharge. Outcome measures were feeding intolerance, NEC (stage ≥ 2), LOS, and mortality. A total of 195 infants (97 from study group and 98 from control group) were analyzed. A total of 46 (47.4%) infants in the study group and 64 (65.3%) infants in the control group ended up with feeding intolerance (p = 0.012). NEC was observed in 11 infants (11.2%) in the control group and only 1 infant (1%) in the study group (p = 0.003). There was a negative correlation between high-dose Zn supplementation and number of culture-proven LOS episodes (p = 0.041). This significance was also present for clinical sepsis, being higher in the control group (p = 0.029). No relationship between high-dose Zn supplementation and mortality and other morbidities (hemodynamically significant patent ductus arteriosus, bronchopulmonary dysplasia, retinopathy of prematurity, and severe intraventricular hemorrhage) was observed. Zn supplementation for VLBW infants is found to be effective to decrease feeding intolerance, NEC, and LOS episodes in this vulnerable population. Current data support the supplementation of VLBW infants with higher than regular dose of Zn. · Higher dose of Zn supplementation is shown to be a beneficial intervention in VLBW infants.. · Zn may decrease feeding intolerance, sepsis or NEC.. · Higher than regular dose of Zn seems to be safe..

A bioinformatic analysis of zinc transporters in intestinal Lactobacillaceae.

As the second most abundant transition element and a crucial cofactor for many proteins, zinc is essential for the survival of all living organisms. To maintain required zinc levels and prevent toxic overload, cells and organisms have a collection of metal transport proteins for uptake and efflux of zinc. In bacteria, metal transport proteins are well defined for model organisms and many pathogens, but fewer studies have explored metal transport proteins, including those for zinc, in commensal bacteria from the gut microbiota. The healthy human gut microbiota comprises hundreds of species and among these, bacteria from the Lactobacillaceae family are well documented to have various beneficial effects on health. Furthermore, changes in dietary metal intake, such as for zinc and iron, are frequently correlated with changes in abundance of Lactobacillaceae. Few studies have explored zinc requirements and zinc homeostasis mechanisms in Lactobacillaceae, however. Here we applied a bioinformatics approach to identify and compare predicted zinc uptake and efflux proteins in several Lactobacillaceae genera of intestinal relevance. Few Lactobacillaceae had zinc transporters currently annotated in proteomes retrieved from the UniProt database, but protein sequence-based homology searches revealed that high-affinity ABC transporter genes are likely common, albeit with genus-specific domain features. P-type ATPase transporters are probably also common and some Lactobacillaceae genera code for predicted zinc efflux cation diffusion facilitators. This analysis confirms that Lactobacillaceae harbor genes for various zinc transporter homologs, and provides a foundation for systematic experimental studies to elucidate zinc homeostasis mechanisms in these bacteria.

Effects of Dietary Zinc on Growth Performance, Digestive Enzyme Activities, Antioxidant Status, and Immune Responses of Sea Cucumber Apostichopus japonicus.

Zinc is an essential micronutrient for organisms involved in regulating various biological processes. This study evaluated the effects of dietary zinc on growth performance, digestive enzyme activities, antioxidant status, and immune responses of sea cucumber Apostichopus japonicus. Five experimental diets were formulated with graded levels of zinc (0, 20, 40, 60, and 80mg/kg, respectively), and the actual dietary zinc values were 31.4, 51.0, 68.2, 91.9, and 110.8mg/kg diet, respectively. Sea cucumbers were fed with diets for 2months. The results showed the growth performance, amylase, and trypsin activities of sea cucumber increased significantly with zinc supplementation, and the best growth performance and enzyme activities were observed at 40mg/kg zinc diet. Zinc supplementation significantly increased activities of superoxide dismutase, catalase, anti-superoxide anion, and inhibiting hydroxyl radical, while significantly reduced the malondialdehyde content. Furthermore, the higher zinc supplementation levels resulted in significantly upregulated immune-related genes of hsp90, p105, rel, and lsz, suggesting that excessive zinc caused oxidative stress. The broken-line regression analysis of specific growth rate indicated dietary zinc requirement in juvenile sea cucumber was ~ 66.3mg/kg diet. Overall, dietary zinc contributes to the growth and immune resistance of juvenile sea cucumber, and our study will provide insights into the rational use of dietary zinc in aquaculture.

Zinc Tolerance of Special Yeasts and Lactic Acid Bacteria for Use in the Food Industry

In order to address human zinc deficiency, fortifying staple foods with zinc is a safe and cost-effective solution. To ensure the nutritional properties and quality of a final product, zinc tolerance of the microorganisms involved in the fermentation is necessary. Bread, which is widely consumed, occupies a substantial place in many people’s diets, and is often based on a sourdough making process; thus, it might be an important headlining product. This study investigated the zinc tolerance of yeasts and lactic acid bacteria that are specifically suited to produce sourdough bread made with cricket powder hydrolysate and wheat flour. Amongst the yeasts, Kazachstania servazzii KAZ2 and Kazachstania unispora FM2 were only slightly affected in regard to cell growth and colony-forming ability when cultured in YPD broth spiked with 0.5 or 1 mM ZnSO4, respectively. Yarrowia lipolytica RO25 showed a higher tolerance for up to 2.5 mM zinc (ZnSO4). All the yeast strains were capable of accumulating zinc in the range between 200 and 400 fg/cell. The heterofermentative lactic acid bacterium Fructilactobacillus sanfranciscensis DG1 appeared to have a moderate zinc requirement and was homeostatically balanced, even under a high 20 mM extracellular ZnSO4 load. A better understanding of zinc homeostasis in yeast and lactic acid bacteria for food industry applications may lead to improvements in zinc fortification, which might contribute to diminishing Zn deficiencies, especially in vulnerable population groups.

The Zinc Transporter SLC39A10 Plays an Essential Role in Embryonic Hematopoiesis.

The role of zinc in hematopoiesis is currently unclear. Here, SLC39A10 (ZIP10) is identified as a key zinc transporter in hematopoiesis. The results show that in zebrafish, Slc39a10 is a key regulator of the response to zinc deficiency. Surprisingly, both slc39a10 mutant zebrafish and hematopoietic Slc39a10-deficient mice develop a more severe form of impaired hematopoiesis than animals lacking transferrin receptor 1, a well-characterized iron gatekeeper, indicating that zinc plays a larger role than iron in hematopoiesis, at least in early hematopoietic stem cells (HSCs). Furthermore, it is shown that loss of Slc39a10 causes zinc deficiency in fetal HSCs, which in turn leads to DNA damage, apoptosis, and G1 cell cycle arrest. Notably, zinc supplementation largely restores colony formation in HSCs derived from hematopoietic Slc39a10-deficient mice. In addition, inhibiting necroptosis partially restores hematopoiesis in mouse HSCs, providing mechanistic insights into the requirement for zinc in mediating hematopoiesis. Together, these findings indicate that SLC39A10 safeguards hematopoiesis by protecting against zinc deficiency-induced necroptosis, thus providing compelling evidence that SLC39A10 and zinc homeostasis promote the development of fetal HSCs. Moreover, these results suggest that SLC39A10 may serve as a novel therapeutic target for treating anemia and zinc deficiency-related disorders.

Extraction and Recovery of Critical Metals from Electronic Waste Using ISASMELT™ Technology

Electronic goods are a major consumer of many critical metals, including copper, nickel, tin, zinc, lead, and precious metals. The processing of end-of-life electronic equipment (E-Scrap) is becoming increasingly important to maintain the supply of the critical metals required globally, and to reduce environmental pollution. Currently, the dominant route for E-Scrap processing is pyrometallurgical processing, with the first stage of processing being reductive smelting to produce a black copper and a ‘clean’ discard slag. The management of the slag in this first step is central to the success of the E-Scrap recycling process. The E-Scrap ISASMELT™ furnace has a highly turbulent bath, providing conditions that generate high rates of zinc fuming and allow a wide range of operable slag conditions. This enables efficient E-Scrap smelting to occur, whilst overcoming the challenges associated with alternative technologies. Operable slag compositions and high zinc fuming are heavily influenced by kinetic processes, with piloting critical to understanding the performance of this process. ISASMELT™ pilot tests were performed, with a wide range of fluxing targets tested to confirm these benefits. The testing demonstrated that high levels of zinc fuming (&gt;80%) are obtained in the E-Scrap ISASMELT™ furnace, decreasing the iron and silica flux additions required to manage the detrimental viscosity effects of zinc in the slag. In addition, it was demonstrated that slags containing high concentrations of alumina (&gt;10 wt%) are operable in an ISASMELT™ furnace. The ISASMELT™ technology was demonstrated to be the only E-Scrap furnace technology able to produce a ‘clean’ discard slag with low concentrations of zinc and minimal fluxing requirements.