Doses Of Zinc Research Articles

Metallothionein I and II Protect against Zinc Deficiency and Zinc Toxicity in Mice

Metallothionein (MT)-bound zinc accumulates when animals are exposed to excess zinc and is depleted under conditions of zinc deficiency, suggesting that MT serves as a means of sequestering excess zinc as well as a zinc reservoir that can be utilized when zinc is deficient. To examine the importance of MT for these processes, mice with null alleles of both MT I and MT II genes were created and the zinc concentration and histological appearance of multiple organs assessed. At birth, the hepatic zinc concentration of these MT-null mice was lower than that of wild-type controls (0.27 ± 0.02 vs. 0.65 ± 0.11 µmol zinc/g tissue, P < 0.05). During the next 3 wk of suckling zinc-replete (95 µg zinc/g diet) dams, the hepatic zinc concentration of controls fell to 0.42 ± 0.04 µmol/g but was unchanged in the MT-null mice (0.28 ± 0.04 µmol/g). The most prominent histological anomaly observed at 3 wk of age was the presence of swollen Bowman's capsules in the kidneys of MT-null mice. When nursing MT-null dams were fed a severely zinc-deficient (1.5 µg/g) diet, kidney development in the MT-null pups was retarded as indicated by the retention of the nephrogenic zone and incomplete tubule development. We suggest that the lack of a hepatic reservoir of zinc jeopardizes the developing kidney in the MT-null mice. In addition to being more sensitive to dietary zinc restriction, MT-null mice are more sensitive to zinc toxicity. When adult mice were challenged with a ramping dose of zinc up to a total of 3700 µmol zinc/kg body weight, MT-null mice had a greater incidence of pancreatic acinar cell degeneration compared with control mice despite accumulating less zinc (2.72 ± 0.46 vs. 1.23 ± 0.52 µmol zinc/g pancreas, control and MT-null, respectively, P < 0.05). The results of these experiments suggest that MT I and MT II can protect against both zinc deficiency and zinc toxicity.

Serum zinc levels in cancer patients are low and difficult to elevate when complicated by liver cirrhosis: A retrospective study.

In this study, we analyzed blood zinc concentration in patients with various cancer types and the degree of improvement in relation to the underlying disease following treatment with zinc preparations. Serum zinc levels of 530 cancer patients whose blood zinc levels were measured at our hospital from 2016 to 2021 were retrospectively examined in accordance with the primary disease. Changes in zinc levels were analyzed in 155 patients whose zinc levels had been measured on 2 or more occasions in accordance with whether they had received zinc preparations. In addition, the concentration course of zinc before and after zinc formulation administration in 73 patients was examined in accordance with the presence or absence of liver cirrhosis complications. Mean serum zinc levels were below normal in all carcinomas measured, and zinc levels were significantly lower in cirrhosis-hepatocarcinoma cases than in other primary disease cases. Furthermore, serum zinc levels in patients who did not receive zinc preparations decreased significantly over time. In patients who received zinc preparations, the elevated levels of zinc after treatment were significantly lower in patients with cirrhosis than in those without cirrhosis. There was a weak inverse correlation between pre-dose zinc concentration and increased zinc concentration in patients with cirrhosis. In the analysis of covariance, the presence of liver cirrhosis was predominantly correlated with elevated zinc per dose. In summary, serum zinc levels in cancer patients are low and especially low in cancer patients with liver cirrhosis compared with those without cirrhosis after the administration of zinc preparations.

INFLUENCE OF ZINC UNDER DEFICIT IRRIGATION ON GROWTH AND PRODUCTIVITY OF HYBRID MAIZE

&#x0D; &#x0D; &#x0D; Zinc (Zn) is an integral part of many enzymes and proteins required by plants for different physiological functions. The field study was conducted to determine the influence of zinc on growth and yield of maize hybrid under skipping irrigations at different growth stages. The experiment comprised of two factors, irrigation treatment viz regular irrigation system (8 irrigations, control) and skip irrigation at knee high and tasseling stages and Zn application treatments i.e. non-Zn application as control, soil application @ 9, 18 and 27 kg ha-1. The experiment was laid out in randomized complete block design (RCBD) with split plot arrangement having three replications. The results showed that application of zinc @ 27 kg ha-1 gave maximum leaf area index (5.16), crop growth rate (20.26 g m-2 day-1), 1000-grain weight (255.03 g), grain yield (5.64 t ha-1) and harvest index (34.5%) than lower doses of zinc and minimum was recorded for control treatment. Similarly, for skipping irrigations, maximum improvement in growth and yield was observed with full irrigations, while irrigation skipped at tasseling stage negatively influenced the growth and yield of hybrid maize than at knee height stage. In conclusion, soil applied zinc at 27 kg ha-1 and normal irrigations helped in improving the growth and yield of autumn planted maize.&#x0D; &#x0D; &#x0D;

Effects of dietary zinc chloride hydroxide and zinc methionine on the immune system and blood profile of healthy adult horses and ponies

ABSTRACT The effects of dietary zinc on the immune function of equines have not been evaluated in detail so far. In the present study, eight healthy adult ponies and two healthy adult horses were fed a diet supplemented with either zinc chloride hydroxide or zinc methionine in six feeding periods of four weeks each (according to maintenance zinc requirement, 120 mg zinc/kg dry matter, and 240 mg zinc/kg dry matter, for both dietary zinc supplements, respectively). All animals received the six diets, with increasing amounts of zinc chloride hydroxide in the feeding periods 1–3, and with increasing amounts of zinc methionine in the feeding periods 4–6. At the end of each feeding period, blood samples were collected for a blood profile and the measurement of selected immune variables. Increasing dietary zinc chloride hydroxide doses increased the glutathione concentrations in the erythrocyte concentrate and the glutathione peroxidase activity in the erythrocyte lysate, decreased the numbers of total leukocytes and granulocytes in the blood, and also decreased the interleukin-2 concentrations in the plasma of the animals. The dietary supplementation of increasing doses of zinc methionine enhanced the mitogen-stimulated proliferative activity of peripheral blood mononuclear cells, and decreased the glutathione concentrations in the erythrocyte concentrate and the glutathione peroxidase activity in the plasma of the animals. The percentage of blood monocytes with oxidative burst after in vitro stimulation with E. coli decreased with increasing dietary zinc concentrations, independently of the zinc compound used. The blood profile demonstrated effects of the zinc supplements on the red blood cells and the bilirubin metabolism of the horses and ponies, which require further investigation. Overall, high doses of dietary zinc modulate the equine immune system, for the most part also depending on the zinc compound used.

Neuro-protective potentials of N-acetylcysteine and zinc against di(2-ethylhexyl)-phthalate-induced neuro-histopathology and dys-regulations of Dopamine and Glutamate in rat brain

This study examined neuro-protective potentials of N-acetyl-cysteine (NAC) and Zinc on expression levels of Dopamine and Glutamate in the Cerebrum, Hypothalami and Pituitary Glands in Di(2-ethylhexyl)-phthalate (DEHP)-induced neurotoxicity in rats. Thirty-six adult male Wistar rats were randomly divided into 6 groups (n = 6). Group 1 was control. Groups 2-6 received oral administrations of 100 mg/kg NAC, 0.5 mg/kg Zinc, 750 mg/kg DEHP, DEHP + NAC doses and DEHP + Zinc doses respectively for 21 days. Brain histology (Heamatoxyline and Eosine technique), histochemical and enzyme-linked-immunosorbent assays of Dopamine and Glutamate in homogenates of Cerebrum, Hypothalami and Pituitary Glands were evaluated. Data were statistically analyzed using One-way-ANOVA with Tukey-post-hoc test at p ≤ 0.05. Histo-pathological evaluations of Cerebrum, Hypothalami and Pituitary Glands showed gross histo-alterations and neurodegenerative changes (Group 4), mild histo- and neuro-degenerative changes (Groups 5 and 6) and normal histology (Group 1). Histochemical analyses showed higher Dopamine levels in Hypothalami (Group 5) and Pituitary Glands (Groups 5 and 6), compared with Group 4. Furthermore, results showed lower Glutamate levels in Cerebrum, Hypothalami and Pituitary Glands of Groups 5 and 6, compared with Group 4. Overall, NAC and Zinc conferred neuro-protection and histo-protection against DEHP-induced neuro-toxicity, neuro-histopathology, decreased Dopamine levels and increased Glutamate levels.

The Effect of Nitrogen (Urea) and Zinc Applied in Different Doses from the Soil and Leaves on the Development, Dry Matter Amount and Mineral Content of Wheat and Corn Plants

This study was carried out to determine the effects of nitrogen and zinc applied in different doses (0.0, 0.5, 1 and 1.5 kg N/ha and 0.0 and 2.5 ppm Zn) to the soil sample taken from Erzurum Atatürk University Faculty of Agriculture Farm land on the dry matter content and mineral content of wheat and maize. It was carried out under greenhouse conditions in 96 pots (2 plants, 2 application methods, 4 nitrogen doses, 2 zinc doses and 3 replications). As a base fertilizer, it was applied to all pots before planting at doses of 1 kg P2O5/ha (TSP: 44.0% P2O5) and 1 kg K2O/ha (K2SO4: 50.0% K2O). Considering the applications, Urea and Zinc fertilizers were applied to the soil before planting in soil application, and from foliar application 5 times in every 2 weeks, starting one week after germination in foliar application. 90 days after sowing, the plants were harvested, dried, their dry weights were determined, the necessary analyzes were made and the plant mineral content was determined. According to the results obtained, nitrogen application from the soil was more effective, and the highest dry matter amount and plant height in both plants were obtained from the soil application of 1.5 kg N/ha urea and 2.5 ppm Zn. Depending on the applications, the dry matter increase is 77.5% in wheat and 80.4% in corn in application from soil. In foliar application, the dry matter increase is 11.4% in wheat and 30.6% in corn. A similar change has also emerged in plant height, the plants applied fertilizer from the soil are taller, with an average of 62.5 cm in wheat and 75.5 cm in maize. These values are on average 55.0 cm and 64.0 cm in plants applied foliar fertilizer. The mineral content of the plants applied foliar fertilizer is higher.

Nature can still be the strongest help against aging and neurodegeneration: the sirtuins way.

Nature can still be the strongest help against aging and neurodegeneration: the sirtuins way.

Effect of Zinc drug on amino acid concentration in liver of white mice, Mus musculus

Zinc is one of the essential trace elements, it plays a key role in many biochemical and functional processes. It is less harmful than many other minerals, in the case of exposure to high doses of zinc, poisoning occurs, and this poisoning may mostly result from the accidental ingestion of household products containing zinc or nutritional supplements, this study was conducted to find out the effects of zinc on the concentration of amino acid. A total of 30 adult white mouse males were taken and divided into three groups; the first group (control) of 10 mice taken with distilled water for 30 days, the second group includes 10 mice that were dose with Zn drug concentration of 50 mg/kg/day for 30 days, the third group includes 10 mice that were dose with Zn drug 100 mg/kg/day for 30 days. In the current study (18) amino acid was recorded in the liver of adult white mouse males as follow: asparagine (Asn), serine (Ser), glutamine (Glu), glycine (Gly), threonine (Thr), histidine (His), citrulline (Cit), alanine (Ala), proline (Pro), taurine (Tau), arginine (Arg), tyrosine (Tyr), valine (Val), methionine (Met), isoleucine (Ile), leucine (Leu), phenylalanine (Phe) and lysine (Lys). Statistical analysis showed high significant differences in the concentration of amino acids between the two groups of the zinc-treated experiment with a concentration (50 and 100) mg/kg/day and control group, as well as significant differences between the two groups of the zinc treatment experiment with a concentration of (50 and 100) mg/kg/day.

Phytotoxicity level and accumulation ability of pot marigold (Calendula officinalis L.) to zinc

The study aims to reveal the effects of different Zn levels on pot marigold. We determined some germination and young seedling properties in the first experiment, and morphological, stomatal, and physiological parameters besides uptake profiles of both Zn and other plant nutrients in the second one. We supplied the water requirement of the seeds with Zn solutions (0, 250, 500, 750, and 1,000 mg l−1) in the first experiment, and We added the same zinc doses as mg kg−1 to the soil of the pots where the plants would grow in the second one. As a result, the inhibitory effects were more prominent in the early seedling stage (especially at 1,000 mg l−1 Zn) than in the germination one. We determined plant growth retardation, decreases in leaf water contents, and increases in membrane damages with higher Zn (≥500 mg kg−1) in the experiment conducted by potting soil. We detected decreases in chlorophyll parameters parallel with the increases in Zn. The alterations in plant zinc contents revealed the accumulation capacity of pot marigold in potting conditions. That TF value >1 in Zn treatments up to 500 mg kg−1 points to the efficiency limit of pot marigold as a Zn-accumulator plant.

Sugarcane Productivity as a Function of Zinc Dose and Application Method

Sugarcane is one of the main crops in Brazilian agriculture. It has high economic and productive potential, but its current productivity is still lacking due to poor nutritional management in both the soil and the plant. Zinc (Zn) directly affects tillering and plant growth, which are critical factors to sugarcane productivity and ratoon longevity. Thus, this research aimed to evaluate the effects of Zn chelate doses (185, 260, and 330 g ha−1) and two application methods (furrow and foliar applications) on the tillering, yield, and quality of sugarcane. The Zn chelate fertilization via furrow at a dose of 330 kg ha−1 provided increases of 13.59%, 17.6%, and 17.0% in stalk height (SH), stalk (TSH) productivity, and sugar (TPH) productivity, respectively. In contrast, Zn foliar application at a dose of 260 g ha−1 provided increases of 3.71%, 20.7%, and 17.0% in SH, TSH, and TPH, respectively. The optimal Zn chelate fertilization in sugarcane cultivation can be performed at a dose of 330 g ha−1 via furrow application at planting or at a dose of 260 g ha−1 via foliar application 145 days after planting.

Comparative analysis of the fertility-enhancing potentials of graded doses of Newbouldia laevis and Zinc in male Wistar rats

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Impact of Fortified Nano Zinc and Iron Composite Capsules on Growth, Yields and Nutrients Accumulation in Cabbage (Brassica oleracea var. capitata L.) and Cauliflower (Brassica oleracea var. botrytis L.)

Synthesized composites were characterized through UV-spectrophotometer, XRD, SEM, EDX and FTIR analysis. SEM and EDX images confirmed surface morphology of ordinary mesoporous nano silica (mNs) and Fe &amp; Zn embedded mNs. In XRD pattern of mNs peaks absence indicate that nano silica synthesized by sol-gel method was amorphous whereas reduced graphene oxide (rGO) synthesized in crystalline form. FTIR spectra of Zn and Fe loaded mNs and rGO showed that encapsulation of zinc and iron by mNS and rGO was successful. Results of experiment indicate, twice foliar application of 60 ppm Zn+ 30 ppm Fe through mNs (T6) and 40 ppm Zn+20 ppm Fe through rGO (T8) exhibited significantly higher economic and biological yields of both crops over conventional and Control. With increasing doses of nano zinc and iron through mNs composite capsules, significant increase in nutrients content and uptake by cabbage and cauliflower was observed in comparison to control. Whereas, increasing doses of nano zinc and iron application through rGO lead to a considerable reduction in nutrient content and thus hamper their uptake. Thus, T6 and T8 treatments were best pronounced in terms of yields, nutrients uptake and enriching biomass by iron and zinc content in cabbage and cauliflower, respectively. Compared to control, quality of cabbage head and cauliflower curd biomass in terms of Fe and Zn content, protein and phenol content were significantly more with 40 ppm Zn+20 ppm Fe (T8) and 60 ppm Zn+30 ppm Fe (T6) through rGO and mNs , respectively. Available zinc and iron in soil was unaffected by application of zinc and Fe through mNs and rGO in crops.

Impact of Moisture Conservation Practices, Seed Inoculation and Zinc Level on Growth and Yield of Chickpea (Cicer arietinum L.)

A field experiment was conducted during the Rabi season of 2020-21 and 2021-22. The experiment was laid out in split-split plot design with 27 treatment combination comprising of three moisture conservation practices viz. flat bed with 2.5 t/ha crop residue, narrow bed and furrow with 2.5 t ha-1 crop residue and broad bed and furrow with 2.5 t ha-1 crop residue in main plot and three seed inoculation viz. control, rhizobium and PSB in sub plot with three zinc level viz. control, 2.5 kg Zn ha-1 and 5.0 kg Zn ha-1 in sub-sub plot. Result shows that the broad bed and furrow with 2.5 t ha-1 crop residue produced significantly all growth parameters and yields attributes as compare to flat bed with 2.5 t ha-1 crop residue and narrow bed and furrow with 2.5 t ha-1 crop residue, respectively. The all growth parameters and yields attributes were significantly recorded higher under seed inoculation with rhizobium over PSB and control. The application of different dose of zinc produced marked significant variation in growth parameter and yield attributes when it increased up to 5.0 kg Zn ha-1. The highest yields were significantly receive in broad bed and furrow with 2.5 t ha-1 crop residue over narrow bed and furrow with 2.5 t ha-1 crop residue and flat bed with 2.5 t ha-1 crop residue, respectively with percent increment 16.33, 24.65, 11.47 and 7.16 in respect of biological yield, grain yield, stover yield and harvest index, respectively over control in pooled data. Seed inoculation with rhizobium produced significantly higher yields parameter over control and PSB with percent increment 5.37, 7.72, 3.84 and 2.34 in biological yield, grain yield, stover yield and harvest index, respectively over control. Application of 5.0 kg Zn ha-1 were produced significantly higher yields with percent increment 6.24, 7.25, 5.56 and 1.01 over control in respect of biological yield, grain yield, stover yield and harvest index, respectively. Therefore, broad bed and furrow with 2.5 t ha-1 crop residue and rhizobium inoculation with dose of 5.0 kg Zn ha-1 were significantly superior in respect to growth and yield attributes and yields of chickpea in present investigation.

Investigating the Effect of Zinc Supplementation on Reducing Depression in Children With Cancer

Background and Objective: Zinc deficiency plays an essential role in mood disorders, such as depression, at different stages of life. This study aimed to investigate the effect of zinc supplementation on depression in children with cancer Materials &amp; Method: This study is a clinical trial conducted on 69 children with cancer. First, the serum zinc level was measured, and the patients completed the Maria Kovacs children’s depression inventory (CDI). Patients with low zinc levels were treated with zinc supplements for one month. Next, they completed the Maria Kovacs CDI, and their serum zinc levels were measured again. The depression score was evaluated and recorded with CDI, and the data were statistically analyzed. Results: The children’s average initial serum zinc level was 77.28 ±25.60 μg/dL, and after the intervention, it was 81.25±26.35 μg/dL. The serum zinc levels before and after the intervention were not significantly different (P=0.126). A total of 8.69% of children suffered from depression. The zinc serum levels in depressed and non-depressed children were not significantly different (P=0.827). Conclusion: This study showed that zinc deficiency is prevalent in all children with cancer, and after the intervention with a standard dose of zinc, no significant change occurred in the level of zinc in the patients. In addition, this intervention did not change the level of depression of these patients. Therefore, it is necessary to conduct more studies to treat these children with a different dose or treatment period.

No Justification for Pharmacological Doses of Zinc in Public Health Nutrition

No Justification for Pharmacological Doses of Zinc in Public Health Nutrition

247 Nutritional Interventions: Our Experiences from the Field

Abstract Dealing with E. coli in the early post-weaning period has been an ongoing theme in the swine industry since many years. Many strategies have been putted in place in order to reduce the issue. Knowledge in nutrition and use of specific feed additive have for sure led the way as solution to overcome those enteric challenge. We also saw a shift over the last 10-15 years for an increase in wean age in order to have a more robust and well-developed pig at weaning. Despite those improvements, use of pharmacological dose of zinc in the early phase post-weaning has remain a key strategy to control E. coli. On the other hand, in some case, efficacy of the historical pharmacological dose of zinc of 2000 to 25000 ppm for the first 2-3 weeks post-weaning seem to be not sufficient to control E. coli challenge. Higher dose and/or use over an extended period of time seem to be more common those days. The reason why we are talking more and more about zinc oxide is that many countries, mostly in Europe, have restricted/banded to use of high dose of zinc in any diet for pig. Limit have now been set at level around 150 ppm. Concern about environmental impact, but mostly about link with antibiotic resistance have been the main concern toward the ban of pharmacological dose of zinc. Canada feed regulations is under review and expectation is that we will also have a ban on high dose of zinc. With that in mind, our group have worked toward finding way to successfully feeding pig with low level of zinc and try to limit the impact of E. coli. We have run multiple research projects throughout the year and we are still conducting project that focus on feeding low level of zinc. Our belief and observation are that the success rely on a broader approach vs the use of single additive to replace the zinc oxide. We are talking about nutritional concept that include a complete review of how we approach the formulation of the diets for nursery pigs. Energy and protein level, use of fiber, specific feed additive, feed and water acidification are some of the strategies that need to be reviewed and evaluated in order to have a complete solution and to ensure better rate of success. The presentation will cover our experience throughout the last 10 years with the change that we implemented and that seem to allow for being successful in feeding pig in nursery with lower zinc oxide level.

374 The Effects of Zinc Sulfate on the in Vitro Feed Digestibility in White-Tailed Deer

Abstract The captive white-tailed deer industry has an estimated economic impact of $1.6 billion, annually. However, nutritional requirements for cervids are determined through research based on sheep and goats. The objective of this study was to determine the effects zinc on in vitro dry matter digestibility for white-tailed does (Odocoileus virginianus). Does (n=2) were euthanized ethically, rumens were collected, and placed into a cooler containing warm water. Rumen contents were agitated and filtered using cheesecloth while applying CO2. The fluid was placed into four separate incubator jars with filter bags containing a 1:1 alfalfa to coastal hay blend. Zinc doses of 0.073 mg/kg/d were added to two of the jars (treatments), and the additional two jars received 0.00 mg/kg/d (control). Following 48 hours of incubation, in vitro true digestibility (IVTD) showed no significant differences (P &amp;gt;.05) between the control and treatment groups. Average dry matter digested in vitro was 91.87% and 95.13%; respectfully. Neutral detergent fiber (NDF) was no different (P &amp;gt;.05) between the two groups. The average digested NDF components for the control were 56.03% and the zinc group had a mean of 57.11%. Additionally, acid detergent fiber (ADF) did not statistically differ. The control group had an average of 74.56% for digested ADF components, and the treatment had a mean of 76.90%. No significant differences were observed in digested organic matter. The control group averaged 79.51% of digested organic matter (OM), and the treatment group averaged 79.38%. This methodology did prove to be viable and functional to evaluate microbial digestion in vitro. This study can be replicated with multiple experimental units to confirm the patterns of increased digestibility. Formal nutritional guidelines can be created to allow for more efficient feeding of deer. In turn, determining nutrient requirements for deer, reducing feed costs for operations, and continue educating the captive deer industry.

A Mechanistic Study on the Anti-Corrosive Performance of Zinc-Rich Polyester/TGIC Powder Coatings

Powder coatings represent an environmentally friendly VOC-free alternative to widely used solvent-borne zinc-rich coatings, with economic and ecological benefits. In particular, powder coatings have several advantageous properties, such as chemical resistance and mechanical strength. However, the performance and characteristics of polyester-based zinc-containing powder coatings remain unknown. In this study, the corrosion performance of polyester powder coatings containing up to 80% zinc is compared. Electrochemical and salt-spray testing results indicate that coatings formulated with 80% zinc demonstrate superior anti-corrosive properties than coatings with lower zinc dosages. Two distinct behavioral phases of the coating with 80% zinc were observed by measurements of open circuit potential (OCP) and polarization resistance (Rp) during immersion tests—a phase indicative of a barrier effect and a phase consistent with galvanic protection. The evolution of the coating was further characterized and interpreted as five stages by electrochemical impedance spectroscopy (EIS), and the mechanistic details were discussed. This UV-resistant single-layer powder coating has the potential to replace the commonly used high-VOC multi-layer liquid coating systems at a significantly lower cost.

Cutting Preference of the Leaf-Heating ant atta sexdens by Seedlings of Eucalyptus urophlylla Submitted to Different Doses of Zinc

Leaf-cutting ants of the genus Atta, also known as leaf-cutting ants, are considered pests in forestry, in various agricultural crops, and also in pastures, causing great damage. Mineral elements are of great importance in increasing crop production and productivity and are involved in the defense mechanism and tolerance of plants to pest and disease attacks, when properly balanced in the soil. The objective of this study was to evaluate the cutting preference of leaf-cutting ants Atta sexdens for Eucalyptus urophylla seedlings submitted to different doses of zinc (Zn) cultivated in a dystrophic Cerrado Latosol. The doses of zinc provided were 0 (control) and 20 mg/dm³ plus 20 mg/L via foliar, in the form of zinc sulfate. The seedlings used were kept in a greenhouse for up to 80 days and then submitted to laboratory evaluation. The leaves of seedlings treated with different doses of zinc were offered in Petri dishes to three colonies of ants from artificial nests of A. sexdens in the laboratory with free choice between treatments. The percentage of leaf tissue cut and transported to the nests was evaluated for 20 minutes between different doses and colonies, and four sequential offers of leaves were made. Through the data obtained, it was observed that there was no preference for cutting the leaves of eucalyptus seedlings treated with different doses of zinc by the colonies of leaf-cutting ants Atta sexdens.

Adverse Effects of Excessive Zinc Intake in Infants and Children Aged 0-3 Years: A Systematic Review and Meta-Analysis.

Zinc supplementation reduces morbidity, but evidence suggests that excessive intakes can have negative health consequences. Current guidelines of upper limits (ULs) of zinc intake for young children are extrapolated from adult data. This systematic review (PROSPERO; registration no. CRD42020215187) aimed to determine the levels of zinc intake at which adverse effects are observed in young children. Studies reporting potential adverse effects of zinc intake in children aged 0-3 y were identified (from inception to August 2020) in MEDLINE, Embase, and the Cochrane Library, with no limits on study design. Adverse clinical and physical effects of zinc intake were synthesized narratively, and meta-analyses of biochemical outcomes were conducted. Random effects models were used to generate forest plots to examine the evidence by age category, dose, dose duration, chemical formula of zinc, and zinc compared with placebo. The Joanna Briggs Institute Critical Appraisal Checklist, Cochrane Risk of Bias 2, and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guideline were employed to assess risk of bias and to appraise the certainty of evidence. Fifty-eight studies assessed possible adverse effects of zinc doses ranging from 3 to 70mg/d. Data from 39 studies contributed to meta-analyses. Zinc supplementation had an adverse effect on serum ferritin, plasma/serum copper concentration, serum transferrin receptor, hemoglobin, hematocrit, and the odds of anemia in ≥1 of the subgroups investigated. Lactulose:mannitol ratio was improved with zinc supplementation, and no significant effect was observed on C-reactive protein, erythrocyte superoxide dismutase, zinc protoporphyrin, blood cholesterol, and iron deficiency anemia. The certainty of the evidence, as assessed using GRADE, was very low to moderate. Although possible adverse effects of zinc supplementation were observed in some subgroups, it is unclear whether these findings are clinically important. The synthesized data can be used to undertake a dose-response analysis to update current guidelines of ULs of zinc intake for young children.