Zinc Excretion Research Articles

Urinary metals and incident diabetes in midlife women: Study of Women’s Health Across the Nation (SWAN)

IntroductionEnvironmental exposure to metals may play a role in the pathogenesis of diabetes; however, evidence from human studies is limited. We prospectively evaluated the associations of 20 urinary metal concentrations...

Accumulation and excretion of zinc and their effects on growth and food utilization of Spodoptera litura (Lepidoptera: Noctuidae)

By exposing larvae of the holometabolous insect Spodoptera litura to the artificial diets supplemented with a range of Zinc (Zn) contents, we investigated Zn ingestion, excretion and accumulation in the insect throughout its life cycle. The effects of Zn stress on the survival, growth and food utilization of S. litura were also determined. Zn concentrations in the body (larvae, pupae, and adults), faeces, exuviates, puparium, eggs increased with the increasing Zn concentrations in the diets, while Zn excretion and accumulation by S. litura in 750 mg/kg Zn treatments was lower than the 600 mg/kg Zn treatment. In the 450 mg/kg Zn treatment, the Zn accumulation in S. litura at different developmental stages differed as follows: larvae > pupa > adult. S. litura ingested Zn via feeding and could excrete most of the Zn via faeces (compared with Zn excretion via exuviates) to reduce its internal Zn accumulation (compared with Zn ingestion). Survival and weight were significantly inhibited, and the prolonged period of development (larvae, pupae) and shortened longevity of adults were found in S. litura exposed to Zn stress greater than 450 mg Zn/kg. In the 150–450 mg/kg Zn treatments, the 6th instar larvae increased their relative consumption rate (RCR) and approximate digestibility (AD) (namely, food eaten) to gain weight, which resulted in greater Zn accumulation in the body. Therefore, below the threshold level (being close to 450 mg/kg Zn), S. litura seemed to have a strong homeostatic adjustment ability (increase the amount of food eaten, thereby increasing AD, RCR and Zn excretion via faeces and exuviates) to sustain their weight, and Zn was beneficial and harmless. Although larvae treated with 750 mg/kg Zn had a similar RCR and AD as the control, a reduced weight gain and prolonged larval period resulted in significantly lower relative growth rate (RGR), which indicated surviving insects may allocate more energy from foods for detoxification than for growth.

The effects of zinc deficiency on homeostasis of twelve minerals and trace elements in the serum, feces, urine and liver of rats

BackgroundZinc deficiency can change the concentrations of minerals and trace elements in the body. However, previous studies still had many limitations.ObjectiveTo reveal the effects of zinc deficiency on homeostasis of 16 minerals and trace elements.MethodsForty-five rats were divided randomly into three groups: normal zinc diet (30 mg/kg), low zinc diet (10 mg/kg), and pair-fed diet(30 mg/kg). The concentrations of 16 minerals and trace elements in serum, feces, urine, and liver were measured by inductively coupled plasma mass spectrometry. The excretion of 16 elements in urine and feces were calculated and compared.ResultsZinc-deficient rats exhibited significant changes in up to 12 minerals and trace elements. The low zinc diet induced decreased excretion of zinc and concentrations of zinc in serum, feces, urine, and liver. Zinc deficiency increased feces concentrations of Mg, Cu, Se, K, Ag, Fe and Mn; decreased the concentrations of Mg, Cu, Se, K in liver and urine, and a diminished amount of Ag was observed in serum. Decreased urinary concentrations of Zn Ca, Mg, Cu, Se, K, Na, As and Cr, suggested that zinc-deficient rats increased the 9 elements’ renal reabsorption. Decreased concentrations of Ca in liver, urine, and feces, decreased excretion in urine and feces and increased serum total Ca suggested that zinc deficiency increased the redistribution of Ca in serum or other tissues. Zinc deficiency increased excretion of Cu, Se, Fe; and decreased the excretion of other 8 elements except for Ag.ConclusionsZinc deficiency changed the excretion, reabsorption and redistribution of 12 minerals and trace elements in rats. Our findings are the first to show that zinc deficiency alters the concentrations of Ag, Cr, and As.Graphical abstract

Iron and Zinc Homeostasis and Interactions: Does Enteric Zinc Excretion Cross-Talk with Intestinal Iron Absorption?

Iron and zinc are essential micronutrients required for growth and health. Deficiencies of these nutrients are highly prevalent among populations, but can be alleviated by supplementation and food fortification. Cross-sectional studies in humans showed positive association of serum zinc levels with hemoglobin and markers of iron status. Dietary restriction of zinc or intestinal specific conditional knock out of ZIP4 (SLC39A4), an intestinal zinc transporter, in experimental animals demonstrated iron deficiency anemia and tissue iron accumulation. Similarly, increased iron accumulation has been observed in cultured cells exposed to zinc deficient media. These results together suggest a potential role of zinc in modulating intestinal iron absorption and mobilization from tissues. Studies in intestinal cell culture models demonstrate that zinc induces iron uptake and transcellular transport via induction of divalent metal iron transporter-1 (DMT1) and ferroportin (FPN1) expression, respectively. It is interesting to note that intestinal cells are exposed to very high levels of zinc through pancreatic secretions, which is a major route of zinc excretion from the body. Therefore, zinc appears to be modulating the iron metabolism possibly via regulating the DMT1 and FPN1 levels. Herein we critically reviewed the available evidence to hypothesize novel mechanism of Zinc-DMT1/FPN1 axis in regulating intestinal iron absorption and tissue iron accumulation to facilitate future research aimed at understanding the yet elusive mechanisms of iron and zinc interactions.

Renal handling of zinc in chronic kidney disease patients and the role of circulating zinc levels in renal function decline.

Zinc deficiency is commonly encountered in chronic kidney disease (CKD). The aims of this study were to assess whether zinc deficiency was related to increased renal excretion of zinc and to the progression of CKD. Plasma and 24-h urinary zinc levels, urinary electrolytes and uromodulin were measured in 108 CKD patients and 81 individuals without CKD. Serum creatinine values were collected for 3years to calculate the yearly change in estimated glomerular filtration rate (eGFR). Multivariable regression analysis was performed to assess the association between baseline zinc levels and yearly change in eGFR. CKD patients had lower circulating zinc levels and higher 24-h urinary zinc excretion than non-CKD participants (612.4 ± 425.9 versus 479.2 ± 293.0 µg/day; P = 0.02). Fractional excretion (FE) of zinc was higher and it significantly increased at more advanced CKD stages. Zinc FE was correlated negatively with 24-h urinary uromodulin excretion (r=-0.29; P < 0.01). Lower baseline plasma zinc levels were associated with a faster yearly decline of renal function in age, gender, diabetes and hypertension adjusted models, but this relationship was no longer significant when baseline eGFR or proteinuria were included. Zinc levels are lower in CKD, and not compensated by reduced renal zinc excretion. The inverse association between urinary zinc excretion and uromodulin possibly points to an impaired tubular activity, which could partly account for zinc imbalance in CKD. These data suggest that zinc status is associated with renal function decline, but further studies elucidating the underlying mechanisms and the potential role of zinc supplements in CKD are needed.

Use of coated nano zinc oxide as an additive to improve the zinc excretion and intestinal morphology of growing pigs1.

Two experiments were designed to explore the effects of coated zinc (Zn) oxide nanoparticles (NZO) on the diarrhea ratio, antioxidant capacity, intestinal morphology, and zinc excretion in growing pigs. In Exp.1, 270 growing pigs (21.88 ± 0.8 kg initial BW) were allocated to three treatments, each for 30 d: (i) control group (CG), basal diet containing Zn-free premix + 100 mg Zn/kg from ZnSO4; (ii) high Zn (HZN), basal diet containing Zn-free premix + 2,250 mg Zn/kg from ZnO; (iii) coated nano ZnO (CNZO), basal diet containing Zn-free premix + 100 mg Zn/kg from coated NZO. In Exp.2, 21 crossbred growing pigs (17.04 ± 0.01 kg initial BW) were allocated to three treatments, each for 28 d: (i) HZN, basal diet containing Zn-free premix + 2,250 mg Zn/kg from ZnO; (ii) low concentration of nano ZnO (LNZO), basal diet containing Zn-free premix + 100 mg Zn/kg from 5% coated NZO material; (iii) high concentration of nano ZnO (HNZO), basal diet containing Zn-free premix + 100 mg Zn/kg from 10% coated NZO material. In Exp. 1, compared with the CG diet, CNZO significantly reduced the diarrhea rate (P < 0.05) and increased the activities of glutathione peroxidase and superoxide dismutase (P < 0.05). Compared with HZN, CNZO decreased the activities of serum alanine aminotransferase, and alkaline phosphatase, as well as the fecal zinc concentration (P < 0.05). In Exp. 2, pigs fed LNZO or HNZO had an increased final BW, average daily weigh and diarrhea rate, and a decreased level of Zn in the plasma, liver, and feces on day 14 compared with the HZN group (P < 0.05). The villous height and villous height/crypt depth ratio of duodenum were higher (P < 0.05) in the HZN group than the HNZO group, whereas the higher villous height of jejunum was observed in the LNZO group compared with that in the HNZO group (P < 0.05). We found that CNZO (100 mg/kg Zn) could improve the antioxidant capacity and reduce fecal Zn emission. However, the diarrhea rate was not effectively suppressed when compared with the HNZO supplementation. Furthermore, coated NZO material of 5% concentration is more effective in improving the morphology of intestinal villus.

Metal and metalloid exposure and oxidative status in free-living individuals of Myotis daubentonii

Metal elements, ubiquitous in the environment, can cause negative effects in long-lived organisms even after low but prolonged exposure. Insectivorous bats living near metal emission sources can be vulnerable to such contaminants. Although it is known that bats can bioaccumulate metals, little information exists on the effects of metal elements on their physiological status. For example, oxidative status markers are known to vary after detoxification processes and immune reactions. Here, for two consecutive summers, we sampled individuals from a natural population of the insectivorous bat, Myotis daubentonii, inhabiting a site close to a metal emission source. We quantified metals and metalloids (As, Ca, Cd, Co, Cu, Mn, Ni, Pb, Se, Zn) from individual fecal pellets. We measured enzymatic antioxidants (GP, CAT, SOD), total glutathione (tGSH) and ratio between reduced and oxidized glutathione (GSH:GSSG) from their red blood cells together with biometrics, hematocrit and parasite prevalence. In general, metal concentrations in feces of M. daubentonii reflected the exposure to ambient contamination. This was especially evident in the higher concentrations of Cd, Co, Cu and Ni close to a smelter compared to a site with less contaminant exposure. Annual differences were also observed for most elements quantified. Sex-specific differences were observed for calcium and zinc excretion. SOD and CAT enzymatic activities were associated with metal levels (principal components of six metal elements), suggesting early signs of chronic stress in bats. The study also shows promise for the use of non-invasive sampling to assess the metal exposure on an individual basis and metal contamination in the environment.

Effects of tapeworm infection on absorption and excretion of zinc and cadmium by experimental rats.

The main objective of this study was to determine how rat tapeworms affect the excretion of zinc and cadmium through rat feces. Male rats (Rattus norvegicus var. alba) were divided into four groups, and the experiment was conducted over a 6-week period. The control groups (00; 0T) were provided with a standard ST-1 rodent mixture and received 10.5mg of Zn/week. Groups P0 and PT were fed a mixture supplemented with the hyperaccumulating plant Arabidopsis halleri at a dosage of 123mg Zn/week and 2.46mg Cd/week. Groups 0T and PT were infected with the rat tapeworm (Hymenolepis diminuta). Fecal samples were collected 24h post exposure. Zinc and cadmium concentrations in rat feces were analyzed using inductively coupled plasma optical emission spectrometry. Tapeworm presence decreased the amount of metals excreted through the feces of the host throughout the entire experiment, with the exception of 1week (control group). No statistically significant differences between zinc excretion rates in the control groups (00 and 0T) were detected at any time throughout the experiment. A statistically significant difference between zinc excretion rates (p < 0.05) in the exposed groups (P0 and PT) was detected in 2 of the 6 monitored weeks. Group PT excreted significantly less cadmium (p < 0.01) than group P0 did in three of the 6weeks. Overall, our results indicate that tapeworms are able to influence the excretion of metals by their host. Tapeworms accumulate metals from intestinal contents. It is not clear whether tapeworms carry out this process before the host tissues absorb the metals from the intestines or the tapeworms accumulate metals excreted from the body of the host back to the intestines. Most likely, it is a combination of both phenomena.

Effects of dietary zinc oxide nanoparticles supplementation on growth performance, zinc status, intestinal morphology, microflora population, and immune response in weaned pigs.

This study evaluated the effects of dietary zinc oxide nanoparticles (nano-ZnOs) on growth performance, zinc status, intestinal morphology, microflora population, and immune response in weaned piglets. A total of 150 weaned piglets (9.37 ± 0.48 kg) were randomly allotted to five dietary treatments and fed with a basal diet (control), or the basal diet supplemented with nano-ZnOs at 150, 300, or 450 mg kg-1 , and 3000 mg kg-1 ZnO for 21 days. After a feeding test, six pigs from the control, 450 mg kg-1 nano-ZnOs and 3000 mg kg-1 ZnO groups were slaughtered. Compared with the control, dietary supplements of nano-ZnOs and ZnO could improve (P < 0.05) average daily weight gain (ADG), average daily feed intake (ADFI), and villus height to crypt depth ratio in the duodenum and jejunum, and decrease (P < 0.05) diarrhea incidence. Zinc retention in the serum, heart, liver, spleen and kidney of pigs supplemented with nano-ZnOs and ZnO was increased (P < 0.05). Nano-ZnOs decreased (P < 0.05) the zinc excretion compared with conventional ZnO. Lower Escherichia coli counts in the cecum, colon, and rectum were observed (P < 0.05) in the nano-ZnOs group compared with the other groups. Compared with the control, ZnO and nano-ZnOs increased (P < 0.05) the serum concentration of IgA, IL-6, and TNF-α, and decreased (P < 0.05) the concentration of IgM. These results indicated that low doses of nano-ZnOs can have beneficial effects on growth performance, intestinal morphology and microflora, and immunity in weanling pigs, which are similar to the effects of pharmacological dosages of conventional ZnO. Nano-ZnOs may reduce mineral excretion, which may reduce environmental challenges. © 2018 Society of Chemical Industry.

Effect of Supplementation of Nano Zinc Oxide on Nutrient Retention, Organ and Serum Minerals Profile, and Hepatic Metallothionein Gene Expression in Wister Albino Rats

A study was conducted to validate the effects of nano form of zinc (NZn) on nutrient digestibility, zinc retention, organ and serum zinc profile, and hepatic metallothionein gene expression in Wistar albino rats (WAR). Nano zinc (NZn) was synthesized through chemical method, by using 0.45M zinc nitrate [Zn(NO3)2.6H2O] and 0.9M sodium hydroxide (NaOH). The NZn particle in its oxide form was characterized by TEM-EDAX and XRD, and found to be in nano range (below 100 nm. Zinc was supplemented to the Wistar albino rats (WAR) through synthetic semi-purified diet either without Zn, or as inorganic zinc (IZn; 25mg/kg), or as synthesized NZn (25, 12.5, 6.25, 3.125 or 50mg/kg DM) for 60days. The zinc content was observed to be significantly (P < 0.05) higher in liver, bone, kidney, and serum due to NZn supplementation where NZn-50 had highest zinc content and control had the least, without affecting Fe, Mn, and Cu. NZn at 12.5mg/kg group rats were either comparable or better than IZn at 25mg/kg in terms of zinc retention, CP digestibility, zinc level in serum, liver, bone, and kidney suggesting its better bioavailability simultaneously also reduced fecal excretion of zinc to the environment. Metallothionein mRNA expression was upregulated in NZn at 25mg/kg and NZn at 50mg/kg than IZn at 50mg/kg. Thus, in WAR, NZn at half of the ICAR recommendation (25mg/kg DM) is as effective as inorganic zinc at 100% of recommended dose.

Effect of Tramadol Addiction Alone and Its Co-abuse with Cannabis on Urinary Excretion of Copper, Zinc, and Calcium among Egyptian Addicts

Effect of Tramadol Addiction Alone and Its Co-abuse with Cannabis on Urinary Excretion of Copper, Zinc, and Calcium among Egyptian Addicts

Zinc as an Essential Nutritional Component of Human Body: A Systemic Review

Introduction: Second to iron, zinc, which is widely distributed in the human body, is the most abundant element in human body. The human body has about 2 to 3 grams of zinc, with the highest concentrations in the liver, pancreas, kidneys, bones and muscles. Other tissues with a higher concentration of zinc include parts of the eye, prostate gland, spermatozoa, skin, hair, fingernail and toenails. Methods: Searches were conducted by two independent researchers in international (PubMed, Web of science, Scopus and Google scholar) and national (SID, Magiran) databases for related studies from the inception of the databases to September 2017 (without time limitation) in English and Persian languages. To ensure literature saturation, the reference lists of included studies or relevant reviews identifed through the search were scanned. Discussion: Absorption and excretion of zinc are carried out through hemostatic mechanisms that are not quite well known yet. The absorption mechanism consists of two paths. Albumin is the most important zinc plasma carrier. The amount transported in blood, in addition to zinc, depends on the availability of albumin. Zinc is a single intracellular ion with structural, catalytic and regulatory roles. Zinc plays important structural roles as part of a multi-protein structure. Key words: Zinc , essential nutritional ,component , human body

Effect of tramadol addiction alone and its co-abuse with cannabis on urinary excretion of Copper, Zinc, and Calcium among Egyptian addicts.

The use of illicit drugs has become a worldwide health problem. Substances with the potential to be abused may have direct or indirect effects on physiologic mechanisms that lead to organ system dysfunction and diseases. The present study aims to investigate the structural and reabsorption integrity of the nephron among Egyptian addicts of tramadol alone and coabused with cannabis. Sixty-five males were included in the study, they were classified into control group (G1=19), tramadol addicts group (G2=18), and tramadol coabused with cannabis addicts group (G3=28). Parameters investigated for structural integrity were urinary levels ofleucineaminopeptidase and N-acetyl-β-D-glucosaminidase, and urinary parameters for reabsorption integrity were levels of copper and zinc as well as calcium, also urinary creatinine was measured. In addition, urinary levels of tramadol and tetrahydrocannabinol were estimated. Among the two addicted groups, all measured parameters were not significantly different in comparison with the control group except for urinary calcium excretion which was found to be significantly increased among the two addicted groups. Both tramadol addiction alone or coabused with cannabis causes increased urinary excretion of calcium, indicating reabsorption dysfunction of calcium without affecting structural integrity along the nephron.

Pengaruh suplementasi zink terhadap parameter hematologi atlet sepatu roda setelah latihan endurance

Background: In sports such as roller skates, endurance can lead to increased inflammation and muscle cell damage, free radical formation, and zinc excretion from sweat and urine that affect the increased redistribution of zinc from blood to tissue. This mechanism causes a decrease in blood zinc levels, erythrocyte numbers and hemoglobin concentrations, increased leukocyte counts and the body’s oxidative stress parameters that have an impact on the athlete’s performance decline. Zinc supplementation may be given to maintain the athlete’s hematologic parameters during endurance exercise.Objectives: To examine the effect of zinc supplementation on serum zinc level, hemoglobin concentration, erythrocyte and leukocyte counts, and blood MDA level of skate athletes after endurance exercise.Method: This study was an experimental clinical trial using pre and post-test designs on 8 athletes incorporated in the Pre-PON DIY Wheels Team. The study was conducted in two periods, one week of endurance exercise without zinc supplementation and one week of endurance exercise with 30 mg/d of zinc supplementation. Blood sampling was performed on the seventh day of each period, before and after endurance training.Results: There was a decrease in erythrocytes and hemoglobin concentration, and a significant increase in leukocyte count after endurance training in both periods (p&lt;0.05), but no significant difference in serum zinc levels and MDA levels after endurance training in both periods (p&gt;0.05). Although there were no significant differences in all athlete hematologic parameters between two treatments (p&gt;0.05), there was an improvement in serum zinc levels, hemoglobin concentrations, erythrocyte, and leukocyte counts.Conclusion: Zinc supplementation 30 mg/day for one week did not have a significant effect on the athlete’s hematology parameters after endurance exercise.

A dynamic model for predicting growth in zinc-deficient stunted infants given supplemental zinc

Zinc deficiency limits infant growth and increases susceptibility to infections, which further compromises growth. Zinc supplementation improves the growth of zinc-deficient stunted infants, but the amount, frequency, and duration of zinc supplementation required to restore growth in an individual child is unknown. A dynamic model of zinc metabolism that predicts changes in weight and length of zinc-deficient, stunted infants with dietary zinc would be useful to define effective zinc supplementation regimens. The aims of this study were to develop a dynamic model for zinc metabolism in stunted, zinc-deficient infants and to use that model to predict the growth response when those infants are given zinc supplements. A model of zinc metabolism was developed using data on zinc kinetics, tissue zinc, and growth requirements for healthy 9-mo-old infants. The kinetic model was converted to a dynamic model by replacing the rate constants for zinc absorption and excretion with functions for these processes that change with zinc intake. Predictions of the dynamic model, parameterized for zinc-deficient, stunted infants, were compared with the results of 5 published zinc intervention trials. The model was then used to predict the results for zinc supplementation regimes that varied in the amount, frequency, and duration of zinc dosing. Model predictions agreed with published changes in plasma zinc after zinc supplementation. Predictions of weight and length agreed with 2 studies, but overpredicted values from a third study in which other nutrient deficiencies may have been growth limiting; the model predicted that zinc absorption was impaired in that study. The model suggests that frequent, smaller doses (5-10 mg Zn/d) are more effective for increasing growth in stunted, zinc-deficient 9-mo-old infants than are larger, less-frequent doses. The dose amount affects the duration of dosing necessary to restore and maintain plasma zinc concentration and growth.

Influence of an Acute Exercise Until Exhaustion on Serum and Urinary Concentrations of Molybdenum, Selenium, and Zinc in Athletes.

The aim of the present study was to determine changes occurring in serum and urine concentrations of essential trace elements with proven essentiality (molybdenum, selenium, and zinc) as a result of performing an acute physical activity until exhaustion in middle- and long-distance runners who live in the same area of Extremadura (Spain). Twenty-one Spanish national middle- and long-distance runners and 26 sedentary students of a similar age were recruited for the study. Both groups ran on a treadmill until exhaustion, starting at a speed of 10 and 8km/h, respectively, and increasing the speed at 1km/h every 400m, without modifying the slope, always within the recommended parameters. Serum and urine samples were obtained from all subjects before and after the tests. Analysis of trace metals was performed by inductively coupled plasma mass spectrometry (ICP-MS). Resting serum and urinary concentrations between groups were compared using the Student t test, and the Wilcoxon test was used to analyze the trends of changes before and after the effort. The results showed that molybdenum concentrations were significantly higher in athletes than in controls (p< 0.01). Selenium (p< 0.05) and zinc (p< 0.01) concentrations were significantly lower in athletes than in controls. When we compared the serum concentrations before and after the test in the controls, only in the case of selenium (p= 0.006), a significant increase was observed after the test. However, this signification disappears with the corrections for hematocrit. Athletes' serum concentrations of Se (p = 0.004) and Zn (p = 0.005) lowered at the end of the test. Also, the results showed that there were no statistical urinary concentration (expressed in μg/g creatinine) changes in Mo and Se. Zn urinary concentration increased at the end of exercise (p = 0.018), since an incremental exercise to exhaustion in middle- and long-distance elite athletes produces a decrease in Se and Zn serum concentrations but Zn urinary concentration increased. In conclusion, athletes show higher serum concentrations of molybdenum and lower serum concentrations of selenium and zinc than sedentary subjects. Additionally, a treadmill test until exhaustion provokes a decrease in serum concentration of selenium and zinc and a higher excretion of urinary zinc. Serum concentrations of Se and Zn should be carried out in order to avoid any possible deficit cases and to establish the optimal supplementation.

Effects of Supplementation of Hot Melt Extrusion Processed Zinc Sulfate on Growth Performance, Nutrients Digestibility, Small Intestinal Morphologyand Excretion of Zinc in Weanling Pigs

Effects of Supplementation of Hot Melt Extrusion Processed Zinc Sulfate on Growth Performance, Nutrients Digestibility, Small Intestinal Morphologyand Excretion of Zinc in Weanling Pigs

Prediction model for manure zinc excretion in laying hens

The objective of this research trial was to compare 2 sources of zinc and different levels of supplementation on manure zinc excretion in laying hens. Bovan White Leghorn hens were used in this study and fed one of 6 dietary treatments. Treatments were in a 2×3 factorial arrangement with 2 sources of zinc (zinc sulfate or Availa®Zn) and 3 levels (40, 80, or 120ppm) and were randomly assigned to 48 cages with 5 hens/cage and 8 replicates/treatment. Hens were housed in a tiered manure-belt housing system providing 627.1 cm2/hen and were given access to 110g/hen/d of feed. Manure samples were collected, and manure zinc content was calculated at 10-week intervals. Data were analyzed using the Glimmix procedure in SAS. There was a significant overall effect of source (P <0.0001) for zinc content, such that hens fed zinc sulfate had lower amounts of zinc excretion. There was also a significant level effect (P <0.0001) in which hens fed 120ppm zinc excreted the greatest amount of zinc. A significant source by level interaction was observed (P <0.0001) for both the overall and individual analyses, such that 120ppm Availa®Zn showed the highest zinc excretion, and both 40ppm zinc sulfate and Availa®Zn showed the lowest zinc excretion. Based on these results, a prediction equation was written for an estimated amount of zinc excretion based on the amount of zinc provided in the diet.

Hydathode function and changes in contents of elements in eddo exposed to zinc in hydroponic solution

To explore the zinc stress response in eddo, plants were grown for 15 d in hydroponic solutions containing 1 (control), 200, and 1000 μM zinc, and the hydathode function and changes in the contents of various elements in these plants were investigated. Under 1000 μM zinc, the dry weights of leaf blades and roots are decreased by 17 and 42%, respectively. The zinc contents in leaf blades, petioles, corms, and roots increased with increasing zinc levels in the solution. The zinc content in roots was 6.57 mg g−1 dry weight, which was 2.8–4.3 times higher than in other plant parts under 1000 μM zinc. These results demonstrate that the severe root damage occurring under 1000 μM zinc is due to higher zinc content in the roots. Under zinc stress, the contents of iron and copper in roots increased, but the contents of magnesium and calcium in petioles, corms, and roots, iron in leaf blades and corms, and manganese in petioles and corms decreased. In the guttation fluid, the concentrations of zinc, magnesium, and potassium increased, while the iron concentration decreased under 1000 μM zinc. Thus, elemental changes occurred in the guttation fluid as well as in different plant parts in eddo. In the 200 and 1000 μM zinc treatments, the amount of zinc eliminated via guttation was 2.8 and 8.5 times higher, respectively, than in the control. The results indicate that guttation partly contributes to the excretion of excess zinc under zinc stress conditions.

Zinc exposure for female workers in a galvanizing plant in Northern Italy.

Very little is known regarding the toxicokinetics of inhaled zinc, in particular in the case of female workers and for modern, low exposure settings. Our aim is to evaluate the relationship of external zinc levels to those of serum and urine for female workers. Eleven female workers (age: 41.7±8 years old, body mass index (BMI): 23.5±4.2 kg/m2) in a galvanizing plant were investigated. Exposure assessment consisted of personal/environmental air samples, and measurement of zinc in serum (collected at the end of first shift of the working week (T1)) and urine, collected before the first shift of the working week (T0), T1 and at the end of the last shift of the working week (T2). Both environmental and personal air samplings for zinc and zinc compounds were below the recommended by the German Research Foundation (Deutsche Forschungsgemeinschaft - DFG) limit values of 2 mg/m3 (7.34±2.8 μg/m3 and 8.31±2.4 μg/ m3, respectively). Serum (118.6±20.9 μg /dl) and urine zinc levels were within reference values for female Italian subjects: the latter increased from 56.4±33.5 μg/dl at T0, to 59.8±37.0 μg/dl at T1, and ultimately 65.4±34.4 μg/dl at T2, but no significant trend was found. End of shift (Spearman's correlation coefficient p value = 0.027) and differential excretion of urinary zinc (both: T0 vs. T1 and T0 vs. T2) were correlated with airborne zinc concentration (p = 0.002 and 0.006, respectively). In general, our data suggests that urine may be a useful medium also for female in order to assess zinc exposure. Further studies are required in order to evaluate whether differential excretion may be useful for the biomonitoring of zinc exposure in the workplaces also for male workers. Int J Occup Med Environ Health 2018;31(1):113-124.