Zn Status Research Articles

Invited Review: Assessing trace mineral status in ruminants, and factors that affect measurements of trace mineral status

The purpose of this article is to review criteria for assessing copper, zinc, manganese, and selenium status in ruminants. Factors that affect measurements of trace mineral status also will be discussed. Published scientific literature was the primary source of information reviewed. When assessing mineral status, it is always good to analyze the diet or forages being consumed for the mineral of interest as well as other minerals that may affect its requirement. Liver is the best indicator of both low and excess Cu status. Plasma Cu concentrations do not decrease below normal values until liver Cu stores are mostly depleted, but a plasma Cu concentration less than 0.4 mg/L suggests Cu deficiency. Severe Zn deficiency can be diagnosed based on extremely low plasma or serum Zn concentrations (less than 0.5 mg/L) or on clinical signs of Zn deficiency that respond to Zn supplementation. It is important to note that infections or acute stress may cause plasma Zn concentrations to temporarily decrease to levels consistent with Zn deficiency. There is currently no reliable indicator of marginal Zn deficiency. Several criteria have been measured in an attempt to assess Mn status. However, no criteria have been demonstrated to accurately predict Mn deprivation. Whole blood or liver Se concentrations are useful in assessing Se status. When interpreting whole blood or liver Se concentrations, it is important to consider whether dietary Se is being derived from organic or inorganic sources. The most appropriate measurement criteria to assess trace mineral status in ruminants depend on the trace mineral being considered. Liver copper is generally a good measure of low as well as excess Cu status. Liver or whole blood Se concentrations are reliable measures of Se status if one takes into account the source of dietary Se. Unless clinical deficiency signs are apparent, it is more difficult to assess Zn and Mn status. In the absence of disease or stress, plasma or serum Zn concentrations below 0.5 mg/L suggest possible severe deficiency. No reliable predictor of marginal Zn deficiency has been determined. Currently, no reliable indicator of Mn status has been identified.

High Sucrose Diet Induces Intestinal Zinc Dyshomeostasis and Permeability

ObjectivesZinc (Zn) is an essential micronutrient that is critical for many physiological processes including glucose metabolism, regulation of inflammation, regulation of intestinal barrier function, and insulin production and secretion. Further, Zn dysregulation is associated with increased risk of chronic inflammatory diseases such as type II diabetes, inflammatory bowel disease, and obesity. However, it remains unclear whether altered Zn status is a symptom or cause of disease onset. Common symptoms of these three inflammatory diseases include the onset of intestinal inflammation and increased intestinal permeability. The specific focus of this work is to investigate how dietary sources of chronic inflammation, such as high sucrose consumption impacts transporter mediated Zn homeostasis and subsequent Zn dependent physiology.MethodsTo study the interactions between high dietary sucrose and Zn homeostasis, we administered 30% sucrose water to mice for 8 weeks. Tissue metal contents were measured by microwave plasma atomic emission spectrometry. Zn transport was measured using radioisotope tracing of 65Zn. Intestine permeability was assessed by FITC-dextran (4 kDa) assay. Protein expression of Zn transporters, inflammatory markers, and tight junction proteins was measured by western blot.ResultsSucrose treatment resulted in systemic changes in steady-state Zn distribution, including a significant increase in plasma Zn and significant decreases in Zn in the liver, pancreas, and white adipose tissue. We observed changes in Zn transport protein expression in the intestine. In agreement with altered transporter expression, Zn transport studies revealed significant dysregulation of Zn transport in both the small intestine and colon. Further, sucrose treatment resulted in induction of both P-STAT3 and P-NF-κB, dysregulation of tight junction proteins ZO-1 and CLDN1, and increased intestine permeability.ConclusionsOur work suggests that chronic high sucrose consumption leads to changes in systemic Zn homeostasis. This links diet-induced changes in Zn homeostasis to the onset of precursors of chronic disease, intestinal inflammation and permeability.Funding SourcesThis work was supported by Cornell University Division of Nutritional Sciences funds to T. B. Aydemir.

Serum zinc levels are associated with obesity and low-density lipoprotein cholesterol in Mexican adults

PurposeLittle is known about the association between serum zinc (Zn) levels and obesity in the Mexican population. Therefore, we tested the association between serum Zn levels, obesity status, and serum lipid levels in a sample of Mexican adults. MethodsAnthropometric data and serum levels of total cholesterol, high- and low-density lipoprotein cholesterol (HDL-C and LDL-C, respectively), and triglycerides were analyzed in 96 Mexican adults. Serum Zn was measured with inductively coupled plasma mass spectrometry. An individual data meta-analysis of the association between serum Zn, overweight, and obesity status was performed in 172 adults from two different provinces in Mexico. ResultsSerum Zn was negatively associated with body mass index (BMI, β = −0.034 ± 0.013, p = 2.0 ×10-6) and obesity (odds ratio [OR]= 0.990, 95% confidence interval [CI]= 0.980–0.999, p = 3.4 ×10-5). The association between Zn level and obesity in Mexican adults was confirmed with an individual data meta-analysis (OR= 0.977, 95% CI= 0.966–0.988, p = 3.4 ×10-5). In addition, a significant interaction effect between serum Zn level and sex was observed on LDL-C level (β = 7.010 ± 3.295, p = 0.037). Serum Zn was negatively associated with LDL-C levels in women (β = −0.188 ± 0.074, p = 0.016). ConclusionOur results confirm the negative association of serum Zn level with obesity. For the first time, we show a sex-specific association between serum Zn and LDL-C levels in a Mexican population. However, further studies are needed in larger and more varied Mexican cohorts to replicate and confirm our findings.

The effects of dietary zinc supplement on intracellular zinc concentration in bovine immune cells

Abstract Zinc (Zn) is one of the most abundant metals in our body and is critical for innate and adaptive immune functions. In humans and mice, Zn deficiency may lead to immunodeficiency, reduced reproductive health, and increased disease susceptibility. However, trace mineral requirements and evidence of Zn dysregulation are poorly defined in cattle. This study aimed to evaluate intracellular Zn concentrations in immune cells from young growing steers with different Zn dietary supplements. Eighteen Angus crossbred steers were stratified by body weight and randomly assigned to two dietary treatments groups: 1) control, no supplemental Zn, or 2) high Zn; 150 ppm of Zn delivered in premixes in total mixed rations. To evaluate the intracellular Zn concentration of immune cells, whole blood cells were loaded with FluoZinTM-3, a fluorescent cell-permeant Zn indicator, then stimulated with Zn pyrithione (100 μM) or TPEN [N,N,N′,N′-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine] (50 μM) to measure maximum and minimum mean fluorescent intensity. Cells were stained with surface antibodies to identify immune cell populations and data were collected by flow cytometry. The intracellular Zn concentrations of circulating CD8 T cells and γδ T cells, but not other populations, differed significantly between treatment groups. These results indicate that intracellular Zn concentration can be influenced by dietary Zn intake, and that certain immune populations are differentially affected by Zn status. This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2020-06540 from the USDA National Institute of Food and Agriculture.

Zng1 is a GTP-dependent zinc transferase needed for activation of methionine aminopeptidase.

The evolution of zinc (Zn) as a protein cofactor altered the functional landscape of biology, but dependency on Zn also created an Achilles' heel, necessitating adaptive mechanisms to ensure Zn availability to proteins. A debated strategy is whether metallochaperones exist to prioritize essential Zn-dependent proteins. Here, we present evidence for a conserved family of putative metal transferases in human and fungi, which interact with Zn-dependent methionine aminopeptidase type I (MetAP1/Map1p/Fma1). Deletion of the putative metal transferase in Saccharomyces cerevisiae (ZNG1; formerly YNR029c) leads to defective Map1p function and a Zn-deficiency growth defect. Invitro, Zng1p can transfer Zn2+ or Co2+ to apo-Map1p, but unlike characterized copper chaperones, transfer is dependent on GTP hydrolysis. Proteomics reveal mis-regulation of the Zap1p transcription factor regulon because of loss of ZNG1 and Map1p activity, suggesting that Zng1p is required to avoid a compounding effect of Map1p dysfunction on survival during Zn limitation.

Albumin-corrected Zn and available free Zn-binding capacity as indicators of Zn status – potential for clinical implementation

We have established and describe two measurement procedures to diagnose possible zinc (Zn) deficiency; albumin-corrected Zn concentration and available free Zn-binding capacity. Reference intervals for both biomarkers were established in healthy adults from the Danish population. The clinical usefulness of the measurement procedures was investigated in patients with cirrhosis and in patients given parenteral nutrition due to short bowel syndrome. The results of both methods indicate that there is a risk of overdiagnosing Zn deficiency based on low plasma Zn concentrations. Needless Zn supplementation may thus be avoided by using the albumin-corrected Zn concentration or available free Zn-binding capacity.

Zinc Variability in Pecan Orchards: Implications for Leaf Sampling and Nutrient Recommendations

Analysis of composite pecan leaf samples typically used to determine need for nutrient applications does not account for variability among trees in the sampled area. To account for this unmeasured variability, pecan orchard block nutrient standards are greater than actual single tree nutrient requirements. In 2018 and 2019, we measured variability in a pecan orchard block by evaluating nutrient status of all trees in a study area consisting of two cultivars (Wichita and Western) grafted on open-pollinated ‘Ideal’ seedlings. Foliar zinc (Zn) coefficient of variation (cv) ranged from 0.186 to 0.255 within individual cultivars and years but was as high as 0.30 when combining cultivars within a year. The ‘Western’ cultivar had higher foliar Zn concentrations than ‘Wichita’, but Zn concentrations were not consistently associated with other leaf nutrient levels, soil Zn status, or other soil properties. Using observed foliar Zn variability, we determined that it is necessary to sample 35 trees for a composite sample to achieve a relative margin of error of 10% and 95% confidence level in a pecan orchard block with more than 1000 trees. We developed field scale foliar Zn recommendations based on individual tree research that indicates a minimum acceptable leaf Zn concentration of ≈15 mg·kg–1 is needed to maintain optimal photosynthetic function in Zn chelate fertigated pecan trees. Assuming a Zn cv of 0.30 and a composite sample comprised of leaves from 35 trees, the minimum acceptable orchard block Zn level to ensure that less than 5% of trees had suboptimal levels of Zn was 27.6 mg·kg–1. An orchard block Zn level below 23.4 mg·kg–1 indicates that more than 5% of trees in the block had suboptimal foliar Zn concentrations.

Marginal Zinc Deficiency Alters Essential Fatty Acid Metabolism in Healthy Men

BackgroundRice biofortification with Zinc (Zn) can improve the Zn status of rice-consuming populations. However, the metabolic impact in humans consuming Zn-biofortified rice is unknown. ObjectivesTo determine the effects of Zn-biofortified rice on lipid metabolism in normolipidemic men. MethodsThe men consumed a rice-based diet containing 6 mg Zn/d and 1.5 g phytate (phytate/Zn ratio = 44) for 2 wk followed by a 10-mg Zn/d diet without phytate for 4 wk. An ad libitum diet supplemented with 25 mg Zn/d was then fed for 3 wk. Fasting blood samples were taken at baseline and at the end of each metabolic period for measuring plasma zinc, glucose, insulin, triglyceride (TG), LDL and HDL cholesterol, fatty acids, oxylipins, and fatty acid desaturase activities. Statistical differences were assessed by linear mixed model. ResultsFatty acid desaturase (FADS) 1 activity decreased by 29.1% (P = 0.007) when the 6-mg Zn/d diet was consumed for 2 wk. This change was associated with significant decreases in HDL and LDL cholesterol. The alterations in FADS1, HDL cholesterol, and TG remained unchanged when Zn intakes were increased to 10 mg/d for 4 wk. Supplementation with 25 mg Zn/d for 3 wk normalized these metabolic changes and significantly increased LDL cholesterol at the end of this metabolic period compared with baseline. FADS1 activity was inversely correlated with FADS2 (rmcorr = –0.52; P = 0.001) and TG (rmcorr = –0.55; P = 0.001) at all time points. ConclusionsA low-zinc, high-phytate rice-based diet reduced plasma HDL cholesterol concentrations and altered fatty acid profiles in healthy men within 2 wk. Consuming 10 mg Zn/d without phytate for 4 wk did not improve the lipid profiles, but a 25-mg Zn/d supplement corrects these alterations in lipid metabolism within 3 wk.

Long-term feeding of Atlantic salmon with varying levels of dietary EPA + DHA alters the mineral status but does not affect the stress responses after mechanical delousing stress.

Atlantic salmon were fed diets containing graded levels of EPA + DHA (1·0, 1·3, 1·6 and 3·5 % in the diet) and one diet with 1·3 % of EPA + DHA with reduced total fat content. Fish were reared in sea cages from about 275 g until harvest size (about 5 kg) and were subjected to delousing procedure (about 2·5 kg), with sampling pre-, 1 h and 24 h post-stress. Delousing stress affected plasma cortisol and hepatic mRNA expression of genes involved in oxidative stress and immune response, but with no dietary effects. Increasing EPA + DHA levels in the diet increased the trace mineral levels in plasma and liver during mechanical delousing stress period and whole body at harvest size. The liver Se, Zn, Fe, Cu, and Mn and plasma Se levels were increased in fish fed a diet high in EPA + DHA (3·5 %) upon delousing stress. Furthermore, increased dietary EPA + DHA caused a significant increase in mRNA expression of hepcidin antimicrobial peptide (HAMP), which is concurrent with downregulated transferrin receptor (TFR) expression levels. High dietary EPA + DHA also significantly increased the whole-body Zn, Se, and Mn levels at harvest size fish. Additionally, the plasma and whole-body Zn status increased, respectively, during stress and at harvest size in fish fed reduced-fat diet with less EPA + DHA. As the dietary upper limits of Zn and Se are legally added to the feeds and play important roles in maintaining fish health, knowledge on how the dietary fatty acid composition and lipid level affect body stores of these minerals is crucial for the aquaculture industry.

Reference cut-offs to define low serum zinc concentrations in healthy 1-19 year old Indian children and adolescents.

Population zinc (Zn) status assessment is based on serum zinc concentration (SZC) cut-offs defined by the International Zinc Nutrition Consultative Group (IZiNCG). The objective of this study is to derive reference SZC cut-offs in apparently healthy 1-19 year Indian children and adolescents using comprehensive national nutrition survey (CNNS) data, and to measure the prevalence of Zn deficiency. Apparently healthy children (n = 12,473) were selected from the CNNS, by including the highest 2 wealth quintiles, and excluding stunted, thin and obese children, and those with CRP > 5 mg/L, anaemia, hypo-albuminemia, diabetes, recent diarrhoea and history of smoking. The 2.5th centile of age-based distributions defined the SZC cut-offs, used to measure the prevalence of Zn deficiency in India, as against the IZiNCG cut-offs. The present study SZC cut-offs were significantly lower, by 10-18 µg/dL, than the IZiNCG cut-offs; more in adolescents. Prevalence of Zn deficiency in the entire CNNS, with these cut-offs, was 2.7 (<10 years) to 5.5 (10-19 years) times lower than with the IZiNCG cut-offs. No geographical state, nor any age group, had Zn deficiency as a serious public health problem (≥20%). In contrast, with IZiNCG cut-offs, 9-27 states (depending on age group) had a public health problem. The present study reference SZC cut-offs for Zn deficiency are lower than the IZiNCG cut-offs, and their rigorous selection from a national sample makes them more appropriate for use in India. A re-examination of the global applicability of IZiNCG recommended cut-offs in other LMICs appears appropriate.

Meta-analysis of Zinc Supplementation on Laying Performance, Egg Quality Characteristics, and Blood Zinc Concentrations in Laying Hens.

There are inconsistent results on the influence of zinc (Zn) supplementation levels on productive indices of laying hens. This study, therefore, uses meta-analysis to synthesis evidence on the effect of inclusion of Zn in chicken diets on performance, egg quality, and blood Zn status of laying hens. Eleven studies were identified and used to analyze the effect of diets with or without Zn supplementation on feed intake, feed conversion ratio (FCR), hen day egg production (HDEP), egg weight (EW), egg mass (EM), Haugh unit (HU) scores, eggshell thickness (EST), eggshell weight (ESW), and blood Zn concentrations in laying hens. Data extracted from the 11 studies included in the meta-analysis were pooled using a random-effects model and expressed as standardized mean differences (SMDs) at a 95% confidence interval (CI). Results indicate that dietary Zn supplementation reduced FCR (SMD = - 0.50g feed/g egg; 95% CI: - 0.68 to - 0.31) and increased HDEP (SMD = 0.33%; 95% CI: 0.18 to 0.48), EW (SMD = 0.14g; 95% CI: 0.03 to 0.25) and EM (SMD = 0.58g/hen/day; 95% CI: 0.22 to 0.95), HU (SMD = 0.64; 95% CI: 0.42 to 0.85), EST (SMD = 0.84mm; 95% CI: 0.45 to 1.23), and plasma Zn concentration (SMD = 4.20mg/dl; 95% CI: 2.99 to 5.40) compared with the controls. In contrast, feed intake and ESW were not significantly different from controls. Restricted subgroup analysis indicated that chosen moderators (age of hen, inclusion level, chicken breed/strain, and supplementation duration) influenced the results of this meta-analysis. There was evidence of significant heterogeneity, and meta-regression indicated that moderators explained most of the sources of heterogeneity. We conclude that dietary zinc supplementation had positive effect on feed conversion ratio, laying performance, aspects of egg quality traits, and blood zinc concentrations in laying hens. The findings from this meta-analysis will help in policy advancements and sustainable use of zinc in the egg production industry.

Impact of dietary zinc and seawater transfer on zinc status, availability, endogenous loss and osmoregulatory responses in Atlantic salmon smolt fed low fish meal feeds

Atlantic salmon fed low fish meal feeds supplemented with zinc (Zn) were studied in two feeding trials. In trial I, Atlantic salmon parr were fed six graded Zn levels (40 to 249 mg kg−1 as ZnSO4) for 8 weeks in freshwater followed by a 4-week seawater phase. In trial II, Atlantic salmon post-smolt were fed for 10 weeks in SW with 10 dietary Zn levels (45 to 280 mg kg−1), either as ZnSO4 or Zn-glycinate. Growth was unaffected by dietary Zn in both trials. Dietary Zn affected concentration of Na + and K+ ions in plasma, branchial and intestinal expression of sodium potassium ATPase, tissue and body Zn status, and cataracts. Seawater transfer significantly reduced apparent availability, body and tissue levels of Zn due to increased endogenous Zn loss. Atlantic salmon post-smolt in seawater improved body and tissue Zn status with increasing dietary Zn levels, irrespective of the Zn source. Body or tissue saturation of Zn occurred at dietary Zn levels between 137 and 156 mg kg−1 with smolts in freshwater and 181 to 218 mg kg−1 in SW post-smolts. Dietary Zn levels below 180 mg kg−1 in low fish meal feeds compromised the Zn status and welfare of Atlantic salmon in seawater.

Dietary l-glutamic acid N,N-diacetic acid improves short-term maintenance of zinc homoeostasis in a model of subclinical zinc deficiency in weaned piglets

AbstractThis study compared the Zn response in selected tissues of weaned piglets fed L-glutamic acid, N,N-diacetic acid (GLDA), while challenged with short-term subclinical Zn deficiency (SZD). During a total experimental period of eight days, 96 piglets were fed restrictively (450 g/d) a high phytate (9 g/kg) diet containing added Zn at 0, 5, 10, 15, 20, 25, 45 and 75 mg/kg with and without 200 mg/kg of GLDA. No animals showed signs of clinical Zn deficiency and no phenotypical differences were observed. Broken line analysis of Zn status parameters such as liver Zn and apparently absorbed Zn indicated that the gross Zn requirement threshold was around 55 mg/kg diet. Supplementation of Zn above this threshold led to a saturation of the response in apparently absorbed Zn and linear increase in liver Zn. Bone and serum Zn responded to the dose in a linear fashion, likely due to the time-frame of Zn homoeostatic adaptation. Inclusion of GLDA into the diets yielded a higher intercept for bone Zn (P &lt; 0·05). Liver Zn accumulation and MT1A gene expression was higher for piglets receiving GLDA (P &lt; 0·05), indicating higher Zn influx. This study indicates that a strong chelator such as GLDA mitigates negative effects of phytate in plant-based diets, by sustaining Zn solubility, thereby improving nutritional Zn availability.

Essential metals, vitamins and antioxidant enzyme activities in COVID-19 patients and their potential associations with the disease severity.

The role of micronutrient deficiency in the pathogenesis of COVID-19 has been reviewed in the literature; however, the data are limited and conflicting. This study investigated the association between the status of essential metals, vitamins, and antioxidant enzyme activities in COVID-19 patients and disease severity. We recruited 155 patients, who were grouped into four classes based on the Adults guideline for the Management of Coronavirus Disease 2019 at King Faisal Specialist & Research Centre (KFSH&RC): asymptomatic (N = 16), mild (N = 49), moderate (N = 68), and severe (N = 22). We measured serum levels of copper (Cu), zinc (Zn), selenium (Se), vitamin D3, vitamin A, vitamin E, total antioxidant capacity, and superoxide dismutase (SOD). Among the patients, 30%, 25%, 37%, and 68% were deficient in Se (< 70.08 µg/L), Zn (< 0.693 µg/mL), vitamin A (< 0.343 µg/mL), and vitamin D3 (< 20.05 µg/L), respectively, and SOD activity was low. Among the patients, 28% had elevated Cu levels (> 1.401 µg/mL, KFSH&RC upper reference limit). Multiple regression analysis revealed an 18% decrease in Se levels in patients with severe symptoms, which increased to 30% after adjusting the model for inflammatory markers. Regardless of inflammation, Se was independently associated with COVID-19 severity. In contrast, a 50% increase in Cu levels was associated with disease severity only after adjusting for C-reactive protein, reflecting its possible inflammatory and pro-oxidant role in COVID-19 pathogenesis. We noted an imbalance in the ratio between Cu and Zn, with ~ 83% of patients having a Cu/Zn ratio > 1, which is an indicator of inflammation. Cu-to-Zn ratio increased to 45% in patients with mild symptoms and 34%–36% in patients with moderate symptoms compared to asymptomatic patients. These relationships were only obtained when one of the laboratory parameters (lymphocyte or monocyte) or inflammatory markers (neutrophil-to-lymphocyte ratio) was included in the regression model. These findings suggest that Cu/Zn might further exacerbate inflammation in COVID-19 patients and might be synergistically associated with disease severity. A 23% decrease in vitamin A was seen in patients with severe symptoms, which disappeared after adjusting for inflammatory markers. This finding may highlight the potential role of inflammation in mediating the relationship between COVID-19 severity and vitamin A levels. Despite our patients’ low status of Zn, vitamin D3, and antioxidant enzyme (SOD), there is no evidence of their role in COVID-19 progression. Our findings reinforce that deficiency or excess of certain micronutrients plays a role in the pathogenesis of COVID-19. More studies are required to support our results.

Serum Vitamin D, Zinc Levels and the Relationship between them in Children and Adolescents.

Along with vitamin D deficiency, a common global health problem in developed and developing countries, zinc deficiency also remains one of the most common micronutrient deficiencies-related public health problems in some parts of the world. Determination of vitamin D and Zn status is important for the growth, development, and health of school-age children, as well as their intellectual achievement and academic performance. In this study, we aimed to evaluate serum 25(OH)D and Zn levels and the relationship between them in a nationally representative sample of Turkish children and adolescents. A total of 541 children and adolescents aged 1 - 16 years were included in our study whose vitamin D and zinc test levels were measured and who applied to the Basaksehir Cam and Sakura City Hospital Pediatric Outpatient Clinic. Cases were examined by dividing them into subgroups according to their vitamin D levels (≤ 15 ng/mL deficiency; 15 - 20 ng/mL insufficiency; ≥ 20 ng/mL sufficiency) and age (< 5 years preschool; 5 - 10 years middle childhood; 11 - 16 years adolescence). The levels of 25(OH)D were lower than 20 ng/mL in 33% of the children. There was deficiency in 80 (15%) and insufficiency in 99 (18%) cases. A statistically significant difference was found in 25(OH)D and Zn levels in groups separated by 25(OH)D level and age (p < 0.001). A positive significant correlation was found between serum 25(OH)D and Zn levels (r = 0.468; p < 0.001). A negative correlation was found between 25(OH) D levels and age (r = -0.261; p < 0.001) and body mass index (BMI) (r = -0.308; p < 0.001). In our study, we found high levels of vitamin D deficiency and insufficiency and a significant positive correlation between serum 25(OH)D and Zn levels in the pediatric population. Based on this possible contribution, we think that providing vitamin D support to children of all ages, including adolescents, and thus improving zinc levels may be beneficial in protecting from diseases that lead to morbidity and mortality as a result of reducing the rate of growth and development retardation, regulating of bone development, and contributing to the development of the immune system.

A Pilot Study on the Concentration of Heavy Metals in Sediments from the Lower Orange River, //Karas Region, Namibia

Global water shortage is caused not just by the physical scarcity of water, but also by gradual deterioration of the quality of water resources such as lakes, streams and rivers with heavy metals. This present study evaluated the status of Mn, Fe, Cr, Cu, Ni, As, Zn, Pb and Cd in sediments from the lower Orange River by Inductively Coupled Plasma Atomic Emission Spectrometry technique by collecting a total of eleven samples, each weighing 1 - 2 kg at the depth of 15 - 20 cm from two observations sites along the lower Orange River and applying pollution indicators such as contamination factor(CF), pollution load index(PLI), index of geo-accumulation(Igeo) and enrichment factor(EF) to assay the nature and extent of heavy metals contamination in sediments. The sequence of the total heavy metal content in descending order was Fe > Mn > Cr > As > Zn > Ni > Cu > Pb > Cd. The results of CF and Igeo showed Mn, Cd, Ni, Zn and Pb were minor sources of sediment contamination since most of the samples were unpolluted and moderately polluted by these metals. However, most sediments were moderate to considerably polluted with Cr, As and Fe suggesting that these were the major pollution sources. The value of PLI at one of the two observation sites was equivalent to the value of baseline level, while the next site indicted quality deterioration of the sediments. The EF revealed that Cr was moderately enriched and arsenic (As) significantly enriched in all the sediments, which suggested contamination due to anthropogenic intervention. Hence, it is recommended that sediment quality be evaluated on a regular basis to avoid further deterioration of the Orange River’s health, which might have detrimental repercussions for both aquatic life and local communities along the river.

Zinc and vitamin C deficiencies associate with poor pulmonary function in children with persistent asthma.

One of the pathophysiologic mechanisms involved in asthma is the increase in oxidative stress. Zinc (Zn), vitamin C (VC), and vitamin E (VE) have antioxidant functions. However, the status of oxidative stress, Zn, VC, and VE in Thai asthmatic children have not been reported. We aimed to evaluate the status of oxidative stress, Zn, VC, VE, pulmonary function tests, and airway inflammation in Thai asthmatic children with persistent asthma. In this cross-sectional study, the data was collected from asthmatic children aged 7-17 years. The plasma PGF2α concentration as a marker of oxidative stress was measured using an ELISA kit. Plasma Zn concentration was measured through atomic absorption spectrophotometry. Plasma VC and VE concentrations were determined using HPLC. Pulmonary function tests were evaluated as forced expiratory volume in first second (FEV₁) and forced vital capacity (FVC), using a spirometer. The status of airway inflammation was determined by measuring fractional exhaled nitric oxide. There were 76 asthmatic children in this study. Seventy-two participants had high oxidative stress. All participants had Zn deficiency. Nearly 40% of participants had VC deficiency. VC deficiency was associated with severe asthma and airway obstruction. Plasma Zn concentrations were positively correlated with FEV₁ (r = 0.27) and FEV₁/FVC ratio (r = 0.65). Deficiency of Zn and/or VC was related to severe asthma and decreased pulmonary function. Nutrition assessment and management should be considered to alleviate asthma burden.

Determination of Critical Limit of Zinc for Rice (Oryza sativa L.) and Potato (Solanum tuberosum L.) Cultivation in Floodplain Soils of Bangladesh

The critical limit for zinc (Zn) varies from 0.38 to 2 µg/g soil depending on the crop and soil type. However, the critical limit for Zn was not explored recently for rice and potato cultivation in the floodplain soils of Bangladesh. A pot experiment was conducted to determine the critical limits of Zn in soil and plants for rice and potato cultivation in two agro-ecological zones (AEZs) of Bangladesh. The soil samples were collected from 20 different locations of Old Brahmaputra and Active Ganges Floodplains with low (&lt;0.9 µg/g), medium (0.91–1.80 µg/g) and high (&gt;1.80 µg/g) Zn status. The experiment was laid out in a factorial and completely randomized design with two levels of Zn (Zn0 and Zn1 (0 and 4.87 kg/ha as Zn sulphate)) applied to 20 different soil samples for rice and potato cultivation using three replications. The critical limit of Zn was determined through a graphical and statistical approach and crops were harvested at the stem elongation (for rice) and tuber filling (for potato) stage. The critical limit of Zn in soil for rice was found to be 0.8 and 0.85 µg/g by graphical and statistical methods, respectively, and both methods revealed the same value (0.73 µg/g) for potato. The critical limit of Zn in rice plants was 23.9 and 24.32 µg/g, whereas in potato plants it was 27.1 and 26.61 µg/g, determined by graphical and statistical methods, respectively. The added Zn supply in soil significantly increased the dry matter accumulation in rice (by 5.6%) and potato (by 10%) compared to no Zn supply. Therefore, a significant positive response to added Zn could be observed on crop growth and yield when the Zn concentration remained below the mentioned critical level for rice and potato cultivation in floodplain soils of Bangladesh.

GIS-based Fertility Assessment and Mapping for Agricultural Research Station, Tandur, Telangana, India

This study was conducted to determine the soil fertility status of the Agricultural Research Station, Tandur of Professor Jayashankar Telangana State Agricultural University (PJTSAU), Vikarabad District, Telangana. To identify the soil sampling points, GPS device was used and collected total of 60 soil samples on grid-based method at a depth of 0–15 cm. The collected samples were analyzed for pH, EC, OC, N, P2O5, K2O, Zn, Cu, Fe and Mn status by following standard methods in the laboratory of Regional Agricultural Research Station, Palem, PJTSAU, Nagarkurnool District of Telangana, and Arc-GIS software was used further to prepare soil fertility maps. Around 37.5% of samples fall in neutral pH, whereas 62.5% samples were found as moderately alkaline reactions and entire farm soils were non-saline. Among the analyzed soil samples, 37.29% samples were in low organic carbon content, and rest of the samples i.e.,62.71% have medium organic carbon content and total samples were low in available N content (&lt; 280 kg ha-1). The analyzed farm samples were medium to high in available phosphorus and potassium (28.67 &amp; 71.33 % of P2O5 and 16.96 &amp; 83.04 % of K2O respectively) content. In contrast, the micronutrients (Zn, Cu, Fe &amp; Mn) exceeded their sufficiency level and suggested for amelioration measures to enhance research efficacy in the farm and to build future research strategies based on the determined soil fertility status.

Soil mineral availability and human mineral status: A review and evidence from Malawi

AbstractWe review literature demonstrating that soil zinc (Zn) and selenium (Se) deficiencies drive human Zn and Se status in some developing contexts, largely through reducing local crop Zn and Se concentration. We then illustrate that in Malawi, human Se status is higher on calcareous soils (the only soils growing high‐Se crops) and close to lakes (which hold Se‐rich fish). We also show that human Se status is predicted by the soil type surrounding and lake proximity of one's nearest market. This makes sense, since Malawians depend heavily on crops from market, particularly during lean season when Se status was measured.