Trace Element Supplementation Research Articles

Effect of parenteral trace element supplementation on oxidative stress and transcriptomic profile of peripheral blood in peripartum dairy cows

Effect of parenteral trace element supplementation on oxidative stress and transcriptomic profile of peripheral blood in peripartum dairy cows

Biological characteristics of marine Streptomyces SK3 and optimization of cultivation conditions for production of compounds against Vibiriosis pathogen isolated from cultured white shrimp (Litopenaeus vannamei).

Antibiotic resistance in shrimp farms has emerged as an extremely serious situation worldwide. The main aim of this study was to optimize the cultural conditions for producing new antibiotic agents from marine Streptomyces species. Streptomyces SK3 was isolated from marine sediment and was identified by its 16S rDNA as well as biochemical characteristics. This microbe produced the highest concentration of bioactive secondary metabolites (BSMs) when cultured in YM medium (YM/2). It produced the maximum total protein (41.8 ± 6.36 mg/ml) during the late lag phase period. The optimum incubation temperature was recorded at 30 °C; BSMs were not produced at ≤10 °C within an incubation period of 3-4 days. The suitable agitation speed was found to be 200 rpm with pH 7.00. The proper carbon, nitrogen, and trace elements supplementation consisted of starch, malt extract, calcium carbonate (CaCO3), and magnesium sulfate (MgSO4). The ethyl acetate extract was found to act strongly against three vibriosis pathogens, Vibrio harveyi, Vibrio parahaemolyticus, and Vibrio vunificus, as indicated by the inhibition zones at 34.5, 35.4, and 34.3 mm, respectively. The extract showed the strongest anti-V. harveyi activity, as indicated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.101 ± 0.02 and 0.610 ± 0.04 mg/ml, respectively. Basic chemical investigation of the crude extract using thin layer chromatography (TLC), bioautography, liquid chromatography tandem mass spectrometry (LC‒MS/MS), Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance (1H-NMR) revealed that the active components were the terpenoid and steroid groups of compounds. They showed carboxylic acid and ester functions in their molecules.

Trace Element Supplementation in Burn Patients: Exploring the Relationship Between Burn Size and Mineral Needs.

Trace element deficiency is an adverse nutritional outcome that can occur with burn injuries, and can interfere with a patient's recovery. The aim of this study was to review the efficacy of our predominately enteral trace element supplementation strategy and determine the burn size at which patients are at risk for trace element deficiency. We reviewed 53 burn patients admitted to our burn center from August 1, 2019 to May 31, 2022 who had their trace element levels and C-reactive protein monitored in two-week increments. Receiver operating characteristic analysis indicated a 22.1% BSAB cutoff for zinc supplementation to prevent deficiency with 91.7% sensitivity and 92.6% specificity, and a 27.5% BSAB cutoff with 88.9% sensitivity and 81% specificity for copper. No patient in our cohort developed selenium deficiency, regardless of burn size. Patients with greater than 30% body surface area burned developed deficiencies in both zinc and copper within the first two weeks of hospitalization. Our results provide guidance for trace element replacement based on burn size.

Genetic information supports a causal relationship between trace elements, inflammatory proteins, and COPD: evidence from a Mendelian randomization analysis.

Dietary factors and nutritional status may be among the risk factors for Chronic Obstructive Pulmonary Disease (COPD). There exists a certain correlation between trace elements and COPD. Through Mendelian Randomization (MR) analysis, we investigated the causal relationships between trace elements, inflammatory proteins, and COPD. We employed MR, multivariable MR (MVMR), and two-step MR (TSMR) approaches to assess the causal links between 15 trace elements and COPD, with 91 inflammatory proteins serving as mediators to further elucidate the tripartite causal relationships. Trace elements such as Folate (OR = 1.293, 95%CI 1.027-1.628; p = 0.029), Vitamin D (OR = 1.331, 95%CI 1.071-1.654; p = 0.010), Vitamin B12 (OR = 1.424, 95%CI 1.108-1.828; p = 0.006), and Iron (OR = 0.741, 95%CI 0.580-0.946; p = 0.016) demonstrated causal relationships with COPD. No causal relationship was observed in reverse MR. After adjusting for BMI, Folate (OR = 1.633, 95%CI 1.098-2.429; p = 0.015), Iron (OR = 0.507, 95%CI 0.31-0.778; p = 0.001), and Vitamin D (OR = 1.511, 95%CI 1.029-2.217; p = 0.034) were identified as independent risk factors for COPD, whereas Vitamin B12 (OR = 1.118, 95%CI 0.751-1.666; p = 0.581) was not. Mediation analysis indicated that CDCP1 (5.76%) may play a mediating role between Iron and COPD. Trace elements such as Folate, Vitamin D, Vitamin B12, and Iron have causal relationships with COPD. After BMI adjustment, Folate, Vitamin D, and Iron emerge as independent risk factors. Furthermore, the inflammatory protein CDCP1 may partially mediate the causal relationship between Iron and COPD, offering a scientific basis for dietary recommendations that could benefit COPD patients. The supplementation of trace elements may be advantageous for individuals suffering from COPD.

Assessment of Trace Element Supplementation in Critically Ill Medical Patients: Selenium and Zinc

Assessment of Trace Element Supplementation in Critically Ill Medical Patients: Selenium and Zinc

Thyroid dysfunction due to trace element deficiency-not only selenium but also zinc.

Levels of serum selenium (Se) and zinc (Zn) decrease when total parental nutrition (TPN) is administered without trace element supplementation for just a few weeks. These trace elements are involved in thyroid hormone metabolism and their deficiencies cause thyroid dysfunction. However, there have been few reports on the details of its clinical course. A 50-year-old man presented with thyroid dysfunction due to Se and Zn deficiency. He had an approximately 70-cm residual small intestine after undergoing intestinal resection and he received TPN without trace element supplementation for one and a half months. Blood tests revealed high levels of thyroid-stimulating hormone (TSH) and free thyroxine (FT4) and low levels of free triiodothyronine (FT3). An abnormal pattern of thyroid function led to suspicion of Se deficiency. Se supplementation raised FT3 levels and lowered FT4 levels to within their respective reference ranges; however, subclinical hypothyroidism persisted with transient TSH elevation. We suspected that Zn deficiency also contributed to the hypothyroidism and, therefore, initiated Zn supplementation, which resulted in normalization of thyroid function. Although thyroid dysfunction has been reported in many studies conducted on Se and Zn deficiencies, hormonal patterns vary between reports. Further accumulation of cases, including detailed data on nutritional status, would be of benefit to elucidate the clinical reality. It is important to consider Se and Zn deficiencies when TSH and FT4 levels are elevated. It should also be noted that transient TSH elevation may be observed with Se supplementation.

Effects of different acidification-resisting strategies on anaerobic digestion of kitchen waste: Methanogenic properties and microbial community shift

Anaerobic digestion (AD) has been widely used as a promising technology for the treatment of kitchen waste (KW). The effects of several acidification-resisting methods were compared, which included the supplementation of trace elements (TEs) and zero-valent iron (ZVI) / powdered activated carbon (PAC), and the application of the sludge domesticated by acetic acid (HAc) and KW as inoculum. The results showed that the supplementation of TEs and ZVI/PAC at total solid (TS) content of 6% and optimal addition doses resulted in an increase in methane yield to 346 and 366 mL/g VS, respectively. In addition, the methane yields of 327 and 241 mL/g VS were obtained by applying the sludge domesticated with KW and HAc as inoculum, while the methane yield of the control was only 89.2 mL/g VS, representing a relative increase of 288%, 311%, 267%, and 170%. The acidification could be alleviated by applying these methods, and also the methanogenic profile was improved. Furthermore, microbial community analysis revealed that the enrichment of Methanosarcina, which enhanced the substrate utilization capacity and subsequently increased methane production, was achieved through the addition of TEs and ZVI/PAC, along with the application of sludge domesticated by KW.

Enhanced methane production with co-feeding spent coffee grounds using spare capacity of existing anaerobic food waste digesters

With increasing coffee consumption worldwide, the efficient and sustainable management of spent coffee grounds (SCG) has become increasingly challenging. This study investigated the anaerobic co-digestion of small amounts of SCG with food waste (FW) at increasing co-feeding ratios of 1:100–1:10 (volatile solids basis) to assess the possibility of SCG treatment using the spare capacity of existing anaerobic digesters. Co-feeding SCG increased methane production compared to FW mono-digestion in the tested range of co-feeding ratios without compromising process stability. Methane yield did not further increase when the SCG/FW ratio increased above 4%, and process failure occurred at a 1:10 co-feeding ratio without trace element supplementation. The enhanced methanogenic performance was attributed to increased protein removal efficiency, which was potentially related to the promotion of peptide hydrolysis. The overall results suggest that co-feeding appropriate small amounts of SCG to FW digesters can be a realistic sustainable option for SCG management.

Targeted cultivation of diatoms in mariculture wastewater by nutrient regulation and UV-C irradiation.

Mariculture wastewater poses environmental challenges due to pollution and eutrophication. Targeted cultivation of diatoms in wastewater can help alleviate these issues while generating beneficial algae biomass, however reliable operating methods are lacking. We proposed a novel method for treating mariculture wastewater that employed UV-C irradiation and nutrient regulation to achieve targeted diatom cultivation. This study first examined growth of four diatom species (Nitzschia closterium, Chaetoceros muelleri, Cyclotella atomus, and Conticribra weissflogii) in mariculture wastewater. C. muelleri and C. weissflogii demonstrated better adaptability compared to N. closterium and C. atomus. Additionally, the growth and nutrient utilization of C. muelleri were studied under varying concentrations of silicate, phosphate, ammonium, and trace elements in wastewater. Optimal growth was observed at 500 μmol/L silicate, 0.6 mg/L phosphate, and 4 mg/L ammonium. Ammonium proved to be a more effective nitrogen source than urea and nitrate in promoting growth at this low level. Surprisingly, trace element supplementation did not significantly impact growth. Finally, this study utilized UV-C irradiation as a pre-treatment method for wastewater prior to nutrient adjustment, significantly enhancing the growth of C. muelleri. Overall, this study provides guidance on regulating key nutrients and pre-treatment method to optimize diatom biomass production from mariculture wastewater. This approach not only addresses environmental challenges associated with mariculture but also contributes to sustainable aquaculture practices through the recovery of valuable aquatic resources.

Effect of Bakofix® Treatment Prior to Estrus Synchronization on Some Fertility Parameters in Anatolian Merino Ewes During the Non-Breeding Season

This study investigated the effect of Bakofix® (a supplement consisting of vitamin E, copper, zinc, manganese, cobalt, selenium, and calcium) on the reproductive performance of Anatolian Merino sheep. A total of 80 clinically healthy sheep were used in the study. They were synchronized with a progesterone-containing sponge outside the breeding season and divided into three groups. The first group (G1, n = 25) was administered Bakofix® treatment 7 days before estrus synchronization, the second group (G2, n = 25) was administered Bakofix® treatment when estrus synchronization began, and the third group served as the control (G3, n = 30). G1 showed a higher estrus response, conception rate, and pregnancy rate compared to the other groups. Particularly remarkable was the 84% pregnancy rate obtained in G1. The fecundity and litter size in G1 were 2.4 and 2.8, respectively, which were higher than those in the other groups. The multiple birth rate in G1 was significantly higher than that in G3, and Bakofix® treatment seven days before synchronization had a positive effect on the multiple birth rate, with a statistically significant difference between the two groups (P < 0.05). Although the multiple birth rate was high in G1, the birth weights of the lambs were not negatively affected. In conclusion, vitamin, mineral, and trace element supplementation can be applied to increase the reproductive performance of Anatolian Merino ewes, especially outside the breeding season and before estrus synchronization, which can lead to increased economic gain.

Effects of dietary supplementation in treatment and control of progression and complications of insulin-dependent diabetes mellitus: a systematic review with meta-analyses of randomized clinical trials.

There is no safe and effective prevention for insulin-dependent diabetes (IDDM) mellitus, which makes it highly dependent on its treatment. This systematic review with meta-analyses of randomized clinical trials investigated the overall effects of dietary supplements of vitamins, minerals, trace elements, and non-essential compounds with antioxidant properties, fatty acids, and amino acids in IDDM. Searches of MEDLINE, Embase, CENTRAL, LILACS, The Grey Literature Report, and ClinicaTrials.gov, and citations from previous reviews were used to identify reports published through July 2023. The Risk of Bias 2 (RoB2) tool was used to analyze the risk of bias and GRADE was used to assess the quality of the results. Fifty-eight studies (n=3,044) were included in qualitative analyses and seventeen (n=723) in meta-analyses. Qualitative analyses showed few positive effects on some metabolic function markers, such as endothelial and renal function and lipid profile. Meta-analyses showed a positive effect of omega-3 on glycated hemoglobin (HbA1c) (RMD=-0.33; 95%CI: -0.53, -0.12, P=0.002; I2=0%; GRADE: low quality; 4 studies) and of vitamin D on fasting C-peptide (FCP) (RMD=0.05; 95%CI: 0.01, 0.9, P=0.023; I2=0%; GRADE: very low quality; 4 studies). Most studies showed bias concern or high risk of bias. A recommendation for dietary supplementation in IDDM cannot be made because of the few positive results within different interventions and markers, the serious risk of bias in the included studies, and the low quality of evidence from meta-analyses. The positive result of vitamin D on FCP is preliminary, requiring further investigation.

Restoring the Stability of Long-Term Operated Thermophilic Anaerobic Digestion of Maize Straw by Supplying Trace Elements

Maize straw has been widely used for the production of energy through anaerobic digestion, but biogas production can be hindered by a lack of trace elemental nutrients. To address this issue, a lab-scale anaerobic plug flow reactor was continuously operated at 55 °C for 300 days, with a hydraulic retention time of 42 days and an organic loading rate of 2.1 g total solids/(L·day). Results from this study showed that between days 101 and 194, the methane yield slightly decreased from 0.26 ± 0.04 to 0.24 ± 0.03 L/g volatile solids (VS), but significant volatile fatty acid accumulation was observed by reaching up to 2759 ± 261 mg/L. After trace elements were added to the reactor, the methane yield increased to 0.30 ± 0.03 L/g VS, with 53% methane content. Around 62% of the total chemical oxygen demand and volatile solids were broken down into methane. Volatile fatty acid levels dropped and stabilized at around 210 ± 50 mg/L, indicating restored process stability. The addition of trace elements increased the abundance of Firmicutes and decreased Synergistetes in bacteria while simultaneously increasing the abundance of Methanosarcina in archaea. In conclusion, trace element supplementation was experimentally found to be necessary for stable thermophilic anaerobic digestion of maize straw.

A study on the correlation between MTHFR and folic acid combined with trace elements for the prevention of fetal malformations in the first trimester of pregnancy.

This study aims to elucidate and examine the intricate interrelation between 5,10-methylenetetrahydrofolate reductase (MTHFR), combined folic acid (FA), and trace element supplementation as a preventive strategy against fetal malformations during the inaugural trimester of pregnancy. Eighty pregnant women selected from our hospital's early obstetrics department from May 2021 to August 2021. Pregnant women are divided into the MTHFR combined group, FA, and trace element group. Comparing the basic data of patients, analyzing adverse reactions in pregnant women, and total birth risk situation, detecting MTHFR gene polymorphisms, and analyzing the correlation between MTHFR and FA in the prevention of fetal malformations in early pregnancy. Compared with the north, the southern region is more prone to FA deficiency. MTHFR degree of the MTHFR combined group was positively correlated with fetal malformations. The deformity rate was negatively correlated with FA and trace elements. Pregnant women in the first trimester may have fetal malformations, and the malformation rate is negatively correlated with FA and positively correlated with MTHFR level. Importantly, the inverse relationship between FA supplementation and malformation incidence underscores its significance as a preventive measure.

Biogas production from fermented sugarcane vinasse: impact of trace elements supplementation

Biogas production from fermented sugarcane vinasse: impact of trace elements supplementation

Minerals and Trace Elements Profile of Apparently Healthy Horses in Ibadan ‎Polo Club, Oyo State, Nigeria

Roles of trace elements and minerals in the overall performance, health and wellbeing of horses cannot be underestimated vis a viz deleterious effects on normal functioning of living organisms posed by prolonged exposure to toxic metals. We evaluated the levels of some minerals and trace elements and compared these parameters among different breed, age and gender. Forty-six apparently healthy horses in Ibadan Polo Club, Ibadan, Nigeria were used for this study. Minerals and trace elements analyses were performed using the inductively coupled plasma optical emission spectrometry (ICP-OES) (Varian Vista Pro®, Varian Medical Systems, Inc., California, USA) and inductively coupled plasma mass spectrometry (ICP-MS) (Varian 820 MS®, Varian Medical Systems, Inc., California, USA). Student’s T-test was applied to establish differences in the values of minerals and trace elements in relation to breed, gender, and age. The results revealed statistically significant differences in the levels of Magnesium (Mg), Iron (Fe), and Iodine (I) and in the level of Silicon (Si), Chromium (Cr), and Iridium (Ir) in minerals and trace elements respectively with significantly higher values in Sudanese compared to Cross-bred horses. Mg, Fe, I, Cr, and Ir values were significantly higher in Mares compared to Stallion. Fe, I, Si, Mo and Cr values were significantly higher in young horses than in adult horses. Conclusively, significant variations were observed in the minerals and trace elements values regarding breed, sex, and age of Horses in Nigeria. Regular supplements of minerals lick and trace elements are advised especially for Cross-bred, Stallion, and adult horses.

Four-week administration of an energy and protein dense oral nutritional supplement improves micronutrient concentrations but does not completely correct deficiencies in institutionalized malnourished older adults.

Poor food intake is common among elderly living in nursing homes, leading to micronutrient deficiency (MD). There are no recommendations for the management of MD in malnourished older adults. We conducted a single arm, open-label, multicenter interventional study in institutionalized malnourished older adults to describe the effect of a 4-week daily energy and protein dense oral nutritional supplementation (ONS, 600 kcal, 30 g protein per unit) containing 50% of the recommended daily micronutrient intake on micronutrient status. Plasma concentrations of vitamins (A, B9, B12, C, E), magnesium (Mg), selenium (Se) and zinc (Zn), and erythrocyte vitamin B9 were measured at baseline and after 4 weeks. Forty-six participants completed the study (age 87.4 ± 6.6). At baseline, the most frequent MD were Se (48%), Zn (35%), Mg (24%) and vitamin C (24%). Plasma concentrations of vitamins B9, B12, C and E, Mg, Se and Zn significantly increased and the proportion of subjects with at least one MD decreased (p = 0.006). However, after 4 weeks, 40% of subjects still had at least one MD. ONS consumption improved micronutrient status but did not correct MD in all participants. Our data suggest that the prescription of vitamin, mineral and trace element supplementation should be considered in institutionalized malnourished older adults in addition to high energy and high protein ONS.

Dietary collagen peptide-chelated trace elements supplementation for breeder hens improves the intestinal health of chick offspring.

Dietary supplementation with trace elements zinc (Zn), iron (Fe) and manganese (Mn) could promote intestinal development and improve intestinal health. There are, however, few studies examining the possibility that maternal original Zn, Fe and Mn could regulate intestinal development and barrier function in the offspring. This study aimed to investigate how the intestinal growth and barrier function of breeder offspring were affected by collagen peptide-chelated trace elements (PTE; Zn, Fe, Mn). PTE supplementation in the diet of breeder hens increased the concentrations of Zn, Fe and Mn in egg yolk. Maternal PTE supplementation improved morphological parameters of the intestine (villi height, crypt depth and villi height/crypt depth) and upregulated the mRNA expression level of leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) in the ileum of chick embryos. Furthermore, maternal PTE effect improved villi height/crypt depth of offspring at 1 and 14 days of age, and upregulated Lgr5, Claudin-3 and E-cadherin mRNA expression in the broiler ileum. Additionally, PTE treatment could enhance the intestinal microbial diversity of offspring. Maternal PTE supplementation increased the relative abundance of Clostridiales at the genus level and decreased the relative abundance of Enterococcus in newborn offspring. Moreover, maternal PTE supplementation ameliorated the elevated nuclear factor kappa B, toll-like receptor 4 and interleukin 1β mRNA expression in the ileum of offspring caused by LPS challenge. Maternal PTE supplementation could promote intestinal development and enhance the intestinal barrier function of chicken offspring. © 2023 Society of Chemical Industry.

The effect of chelating compounds on the meat qualities of beef

An important aspect is the problem of balanced micronutrient nutrition in diets, which arises from insufficient macro- and micronutrients in soil and feed. Some of these elements act as components of biologically active compounds and regulate various metabolic processes. A lack or excess of these elements can lead to significant metabolic disorders in the animal's body and decreased productivity. The ratio imbalance occurs when a violation of metabolism accompanies fattening young cattle concerning mineral substances, a decrease in the productivity and stability of animals, and deterioration of veterinary and sanitary indicators and meat quality. The research aimed to reveal the effect of enriching rations with deficient microelements in combination with chelating compounds (methionates) on the productivity of experimental cattle. The use of trace elements and their chelated compounds, such as methionates and other biologically active substances, has advantages. This helps to reduce the assimilation of heavy metals and radionuclides from contaminated feed and water. Chelated complexes of microelements easily penetrate through cell membranes, which allows you to have a targeted effect on the metabolism of substances and energy and correct the deficiency of microelements in the corresponding biogeochemical zones. With the addition of trace element supplements and their chelated compounds, the slaughter yield of bulls of the 2nd, third, and fourth experimental groups increased by 0.15, 1.48, and 2.26 kg, respectively, compared to the control group. The yield of high-grade meat increased by 9.18, 11.02, and 13.9 kg, respectively, for the control. Also, the first-grade muscle tissue yield increased by 11.35, 12.95, and 15.1 kg compared to the control. Correction of the rations of experimental animals with deficient trace elements in the form of salts and their chelated compounds (methionates) contributed to improving beef's physical and chemical composition and nutritional value. Thus, we conclude that the fourth experimental group, which was fed microelements in the form of chelated compounds (methionates), has the best indicators in terms of all parameters, the second and third experimental groups, which were fed inorganic salts of deficient microelements, have slightly lower indicators, respectively. In the future, we will use chelating compounds of deficient trace elements to improve beef's physiological and morphological indicators.

Therapeutic effect of trace elements on multiple myeloma and mechanisms of cancer process.

In the human body, trace elements and other micronutrients play a vital role in growth, health and immune system function. The trace elements are Iron, Manganese, Copper, Iodine, Zinc, Cobalt, Fluoride, and Selenium. Estimating the serum levels of trace elements in hematologic malignancy patients can determine the severity of the tumor. Multiple myeloma (MM) is a hematopoietic malignancy and is characterized by plasma cell clonal expansion in bone marrow. Despite the advances in treatment methods, myeloma remains largely incurable. In addition to conventional medicine, treatment is moving toward less expensive noninvasive alternatives. One of the alternative treatments is the use of dietary supplements. In this review, we focused on the effect of three trace elements including iron, zinc and selenium on important mechanisms such as the immune system, oxidative and antioxidant factors and cell cycle. Using some trace minerals in combination with approved drugs can increase patients' recovery speed. Trace elements can be used as not only a preventive but also a therapeutic tool, especially in reducing inflammation in hematological cancers such as multiple myeloma. We hope that the prospect of the correct use of trace element supplements in the future could be promising for the treatment of diseases.

Effect of trace element supply on plant growth and mineral nutrition of Cyclopia longifolia Vogel L. a Honeybush tea plant growing on a farmer's field in the Cape fynbos, South Africa

Cyclopia longifolia Vogel L. is endemic to the Cape fynbos, and cultivated for the production of Honeybush tea, a herbal beverage with health benefits and economic potential in the cosmetic and nutraceutical industries. In this study, field plants were supplemented with different levels of Cu, Mo, Mn and Zn using 0, 0.5, 1.0 and 1.5 mM solutions of Na2MoO4·2H2O and MnSO4·2H2O and 0, 1.0 and 1.5 mM solutions of ZnSO4·7H2O and CuSO4·5H2O in a split-application. Plant shoots were harvested at 300 days after fertilization for biomass determination and analysis of mineral nutrients. The results showed significantly increased shoot dry matter yield of C. longifolia in response to Mn, Cu, Zn and Mo supplementation under field conditions, and was highest at the 1.5 mM level of each applied micronutrient. These results suggest that field fertilization of Cyclopia plants can lead to increased plant growth and greater tea yield, in addition to overcoming nutrient mining from the annual harvests of plant shoots for making tea. Furthermore, supplying Mn, Zn, Cu and Mo to C. longifolia also significantly increased the concentrations and amounts of P, K, Ca, Mg, Cu, Zn, Mn and B in shoots relative to the zero controls, suggesting an increase in tea quality with trace element supplementation. However, the shoot concentrations of N and Fe were markedly reduced with increasing supply of Mn, Cu, Zn and Mo to C. longifolia plants, an indication of mineral-to-mineral antagonism in the plant rhizosphere.