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Soil salinity is a major nutritional challenge with poor agriculture production characterized by high sodium (Na + ) ions in the soil. Zinc oxide nanoparticles (ZnO NPs) and biochar have received attention as a sustainable strategy to reduce biotic and abiotic stress. However, there is a lack of information regarding the incorporation of ZnO NPs with biochar to ameliorate the salinity stress (0, 50,100 mM). Therefore, the current study aimed to investigate the potentials of ZnO NPs application (priming and foliar) alone and with a combination of biochar on the growth and nutrient availability of spinach plants under salinity stress. Results demonstrated that salinity stress at a higher rate (100 mM) showed maximum growth retardation by inducing oxidative stress, resulted in reduced photosynthetic rate and nutrient availability. ZnO NPs (priming and foliar) alone enhanced growth, chlorophyll contents and gas exchange parameters by improving the antioxidant enzymes activity of spinach under salinity stress. While, a significant and more pronounced effect was observed at combined treatments of ZnO NPs with biochar amendment. More importantly, ZnO NPs foliar application with biochar significantly reduced the Na + contents in root 57.69%, and leaves 61.27% of spinach as compared to the respective control. Furthermore, higher nutrient contents were also found at the combined treatment of ZnO NPs foliar application with biochar. Overall, ZnO NPs combined application with biochar proved to be an efficient and sustainable strategy to alleviate salinity stress and improve crop nutritional quality under salinity stress. We inferred that ZnO NPs foliar application with a combination of biochar is more effectual in improving crop nutritional status and salinity mitigation than priming treatments with a combination of biochar., (© 2024. The Author(s).)

An 8-week feeding trial was carried out to examine the effect of different sources of dietary Zn on some physiological responses (performance, digestive enzymes activity, hemato-biochemical parameters, antioxidant status and liver histology) of Siberian sturgeon, Acipenser baerii. For this purpose, fish with an average weight of 100 g ± 5 were randomly allocated into four groups including control, inorganic zinc (Zn-sulfate), organic zinc (Zn-gluconate), and zinc-oxide nanoparticles (ZnO-NPs) at 50 mg Zn kg - 1 feed. Improved growth indices, namely weight gain (WG) and specific growth rate (SGR) and feed conversion ratio (FCR) were observed in fish fed Zn-gluconate supplemented diet (P < 0.0.5). The highest digestive enzymes activity was recorded in fish fed Zn-gluconate supplementation (P < 0.0.5). Hematological indices significantly increased in fish fed diet containing ZnO-NPs (P < 0.0.5). Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of fish fed ZnO-NPs contained diet were the highest (P < 0.0.5). The highest serum superoxide dismutase (SOD) and catalase (CAT) enzymes activity were observed in fish fed ZnO-NPs and inorganic/organic Zn contained diets, respectively. While liver tissue SOD and glutathione peroxidase (GPx) enzymes activity Zn were significantly increased in fish fed inorganic/organic Zn supplemented diet (P < 0.0.5). Based on liver histological results, a severe tissue changes such as necrosis and pyknosis were observed in fish fed with Zn-sulfate in comparison to other forms. In conclusion, the data of the present study confirmed that organic Zn (mainly) and nano-Zn (to some extent) could be more efficient Zn sources in Siberian sturgeon., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

The harmful influences of global warming on rabbit reproduction and industry attract global attention. Zinc (Zn) is an important trace element with a wide list of functions in the male reproductive system. The aim of this study was to estimate the effects of different forms of zinc supplementation, as organic (Zn methionine), nano (nano Zn oxide) as indirect way to minimized it impact on environment, and inorganic (Zn sulphate) on physiological parameters, semen quality, anti-oxidative status, hormonal profiles of male rabbits subjected to server heat stress. Thirty-six V-line bucks (6-7 months old, 2842.29 ± 34.46 g weight) were randomly distributed to 4 groups, bucks in 1st group (control group, Con) fed basal diet without Zn supplementation, the 2nd, 3rd and 4th groups fed basial diet with 30 mg/kg of zinc methionine (Zn-Met), nano zinc oxide (ZnO-NPs), and zinc sulphate (Zn-S), respectively for a period of 10 weeks suffered from severe heat stress of environmental ambient temperature (over 32 of temperature humidity index, THI). Semen samples were collected and evaluated for volume, pH, motility, concentration, viability, initial fructose, and seminal plasma antioxidant concentration. Liver, kidney function, hormonal and antioxidant profile were measured in blood serum. The results revealed that, compared to control, all forms of Zn supplementation used significantly improved kidney function (creatinine), serum antioxidant (SOD and CAT), physiological parameters, especially on 1st month of the experiment, and seminal plasma antioxidant (SOD and CAT) of heat stressed bucks. Likewise, semen quality in terms of sperm concentration, sperm viability, and initial fructose enhanced significantly (P ≤ 0.05) by ZnO-NPs supplementation. Zinc methionine supplementation significantly improved liver function and decreased seminal plasma TBARs. Treatments with Zn-Met and ZnO-NPs increased seminal TAC and blood testosterone levels with reduced blood cortisol levels compared to other groups. Severe heat stress could be counteract by inclusion Zn with studied forms Zn-Met and ZnO-NPs at recommended dose (30 mg/kg diet) to improve semen quality and antioxidant status., (© 2023. Springer Nature Limited.)

The experiment was conducted to investigate the effect of supplementary different levels of zinc-threonine (Zn-Thr) and zinc oxide (ZnO) on the Zn bioavailability, biological characteristics and performance of honey bees (Apis mellifera L.). The experiments were carried out with seven treatments in a completely randomized design with five replicates for each treatment. During the experiment, groups were fed a basal diet without extra zinc (10.4 mg Zn/kg diet), and it was used as the control diet and 3 levels of 20, 40, and 60 mg Zn/kg were added to the diet by ZnO and Zn-Thr sources. The results showed that different levels of organic Zn significantly increased Zn and Fe content in the carcass of caged bees compared to different levels of inorganic Zn and control groups. Also, honey bees fed with levels of 40 and 60 mg Zn/kg Zn-Thr supplementation significantly had lower Malondialdehyde (MDA) concentration and higher ash content, protein content, superoxide dismutase (SOD) activity in their tissues. In addition, they showed more life span, feed intake, population, brood rearing, and hive weight gain (p < 0.05). Totally, the results of the present experiments revealed that diets supplied with organic Zn compared to inorganic Zn play significant roles in the improvement of Zn bioavailability, biological characteristics, and performance in honey bees., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Zinc-enriched mesoporous bioactive glasses (MBGs) are bioceramics with potential antibacterial and osteogenic properties. However, few assays have been performed to study these properties in animal models. In this study, MBGs enriched with up to 5% ZnO were synthesized, physicochemically characterized, and evaluated for their osteogenic activity both in vitro and in vivo. The ZnO MBGs showed excellent textural properties despite ZnO incorporation. However, the release of Zn 2+ ions inhibited the mineralization process when immersed in simulated body fluid. In vitro assays showed significantly higher values of viability and expression of early markers of cell differentiation and angiogenesis in a ZnO-content-dependent manner. The next step was to study the osteogenic potential in a sheep bone defect model. Despite their excellent textural properties and cellular response in vitro, the ZnO MBGs were not able to integrate into the bone tissue, which can be explained in terms of inhibition of the mineralization process caused by Zn 2+ ions. This work highlights the need to develop nanostructured materials for bone regeneration that can mineralize to interact with bone tissue and induce the processes of implant acceptance, cell colonization by osteogenic cells, and regeneration of lost bone tissue.

Background: Organic zinc sources for the treatment of zinc deficiency or as a supplement to a specific diet are increasingly needed. Zinc-enriched yeast (ZnYeast) biomass is a promising nutritional supplement for this essential micronutrient. However, these products are not yet authorized in the European Union and a clear position from the European Food Safety Authority on the use of ZnYeast as a zinc supplement is pending, demanding more data on its bioavailability., Objective: The study aimed to produce a ZnYeast based on a Saccharomyces genus (S. pastorianus Rh), characterize its zinc enrichment quota, cellular distribution of zinc, and evaluate its zinc bioavailability after human digestion by comparing it to commonly used inorganic and organic zinc supplements (ZnO, ZnSO 4 , zinc gluconate, and zinc aspartate)., Method and Main Findings: The zinc-enriched S. pastorianus Rh contained 5.9 ± 1.0 mg zinc/g yeast, which was predominantly localized on the cell surface according to its characterization on the microscale with scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX). Combined experiments with a human in vitro digestion model and the in vitro intestinal cell model Caco-2 showed that intestinal zinc bioavailability of digested yeast biomass was comparable to the other zinc supplements, apart from ZnO, which was somewhat less bioavailable. Moreover, zinc released from digested ZnYeast was available for biological processes within the enterocytes, leading to mRNA upregulation of metallothionein, a biomarker of intestinal zinc status, and significantly elevated the cellular labile zinc pool., Conclusions: Our findings demonstrated that ZnYeast represents a suitable nutritional source for organically bound zinc and highlighted optimization strategies for future production of dietary ZnYeast., (Copyright © 2022 Elsevier GmbH. All rights reserved.)

Growth performance and physiological responses of nursery piglets when fed enzymatically treated yeast (HY40) and pharmacological ZnO alone or in combination were investigated. A total of 144 pigs (21 d old, BW 7.32 ± 0.55 kg) were placed in 36 pens (4 pigs/pen). Pigs were randomly assigned to one of four dietary treatments (n = 9): 1) control corn-wheat-soybean meal diet (control), 2) control + HY40 (HY40), 3) control + (ZnO) and 4) control + HY40 + ZnO (HY40+ZnO). Inclusion of HY40 and ZnO was 0.5% and 3,000 ppm in phase I (days 0 to 14), respectively, and halved in phase II (days 15 to 42). All diets contained 0.2% TiO2 for determination of apparent total tract digestibility (ATTD) of components. Body weight and feed disappearance were recorded weekly. One pig per pen was killed for organ weights, blood, and tissue samples on day 14. Except for phase II, when HY40 + ZnO pigs had greater average daily feed intake (P = 0.004) than all other treatments, there were no (P > 0.05) interactions between HY40 and ZnO on growth performance. Pigs fed HY40 or ZnO containing diets were heavier (P < 0.05) than pigs fed without by the end of the study. On day 14, pigs fed additives exhibited higher (P ≤ 0.009) ATTD of dry matter (DM) and gross energy (GE) than control pigs. On day 28, pigs fed control, HY40, and HY40 + ZnO had greater (P ≤ 0.022) ATTD of DM, crude protein, and GE than piglets fed ZnO only. Pigs fed HY40 + ZnO had lower ileal digesta Escherichia coli concentration (P < 0.05) than HY40 and control pigs. Ileal digesta of pigs fed ZnO diets had higher lactobacillus to E. coli ratio (1.44 vs. 1.20; P = 0.001), exhibited higher concentrations of acetic (P = 0.01) and butyric acid (P = 0.01) but lower lactic (P = 0.02) and total short chain fatty acids (P = 0.033) than pigs fed non-ZnO diets. Greater (P < 0.05) mRNA expression of nutrient transporters, tight junction proteins, and fecal excretion of zinc (Zn) was observed in ZnO pigs relative to non-ZnO pigs. Pigs fed HY40 diets had greater (P = 0.002) villus height to crypt depth ratio (VH:CD) than non-HY40 pigs. The concentration of plasma IgA was higher (P = 0.04) in HY40 + ZnO pigs relative to other pigs, whereas HY40 pigs showed higher (P < 0.001) jejunal IgA than non-HY40 pigs. Although the mode of action of HY40 and ZnO differed, the present study indicated that HY40 improved growth performance and jejunal function and immunity, making HY40 an effective alternative to pharmacological ZnO in nursery pigs feeding programs., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Background: Cardiovascular health is strongly influenced by diet. The levels of inflammatory factors like ICAM-1 and VCAM-1 are high in patients with atherosclerosis or predisposing factor for heart disease. Antioxidant and anti-inflammatory functions are attributed to zinc. We systematically reviewed cell culture, human or animal studies for determining the relationship between zinc status and ICAMs or VCAM-1 levels., Methods: PubMed, Google Scholar, Scopus, and Cochrane databases from database inception till 30th August 2020 were systematically searched to obtain any possible article for inclusion., Results: After screening and removing unrelated or duplicate articles by the title and abstract by two independent reviewers, 15 articles were included. Results indicating an inverse relationship between zinc status with ICAM-1 or VCAM-1 levels and the development of endothelial inflammation, plaque formation, or atherosclerosis. A direct relationship between zinc status and PPAR-α or γ levels was also observed. Zinc oxide (ZnO), zinc nanoparticles, or ions can cause endothelial activation and increased levels of ICAM-1 and VCAM-1., Conclusion: Normal function of the endothelium is linked with zinc level. Zinc deficiency causes atherosclerosis, most probably via increased production of ICAM-1 and VCAM-1; and decreased expression of PPAR-ɑ and PPAR-γ receptors. Contrarily, endothelial activation and increased ICAM-1 and VCAM-1 levels can be caused by ZnO, zinc nanoparticles, or zinc ions., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Influenza A viruses (IAV) and SARS-CoV-2 can spread via liquid droplets and aerosols. Face masks and other personal protective equipment (PPE) can act as barriers that prevent the spread of these viruses. However, IAV and SARS-CoV-2 are stable for hours on various materials, which makes frequent and correct disposal of these PPE important. Metal ions embedded into PPE may inactivate respiratory viruses, but confounding factors such as adsorption of viruses make measuring and optimizing the inactivation characteristics difficult. Here, we used polyamide 6.6 (PA66) fibers containing embedded zinc ions and systematically investigated if these fibers can adsorb and inactivate SARS-CoV-2 and IAV H1N1 when woven into a fabric. We found that our PA66-based fabric decreased the IAV H1N1 and SARS-CoV-2 titer by approximately 100-fold. Moreover, we found that the zinc content and the virus inactivating property of the fabric remained stable over 50 standardized washes. Overall, these results provide insights into the development of reusable PPE that offer protection against RNA virus spread.

A green method was used for the preparation of functional carboxymethyl cellulose (CMC) hydrogel crosslinked by divalent zinc ions and incorporated with zinc oxide nanoparticles (ZnO) without using alkaline reagents. In the process, sodium carboxymethyl cellulose was used not only as a hydrogel matrix but also for the release of free hydroxyl groups, which increases the pH of the reaction mixture, consequently leading to the formation of ZnO. The chemical structure and morphology of the hydrogels were characterized using FTIR and FE-SEM analysis, respectively. The water absorption capacity of the hydrogels was studied as a function of temperature and pH. The results of FE-SEM showed the formation of ZnO particles in the hydrogel, while the water absorption capacity results supported the formation of zinc ion cross-linking within the carboxymethylcellulose chains. The CMC/ZnO nanocomposite hydrogel exhibited strong antimicrobial activity against pathogenic bacteria E. coli and L. monocytogenes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Zinc ions (Zn2+) are important messenger molecules involved in various physiological functions. To maintain the homeostasis of cytosolic Zn2+ concentration ([Zn2+]c), Zrt/Irt-related proteins (ZIPs) and Zn2+ transporters (ZnTs) are the two families of proteins responsible for decreasing and increasing the [Zn2+]c, respectively, by fluxing Zn2+ across the membranes of the cell and intracellular compartments in opposite directions. Most studies focus on the cytotoxicity incurred by a high concentration of [Zn2+]c and less investigate the [Zn2+]c at physiological levels. Zinc oxide-nanoparticle (ZnO-NP) is blood brain barrier-permeable and elevates the [Zn2+]c to different levels according to the concentrations of ZnO-NP applied. In this study, we mildly elevated the [Zn2+]c by ZnO-NP at concentrations below 1 μg/ml, which had little cytotoxicity, in cultured human neuroblastoma SH-SY5Y cells and characterized the importance of Zn2+ transporters in 6-hydroxy dopamine (6-OHDA)-induced cell death. The results show that ZnO-NP at low concentrations elevated the [Zn2+]c transiently in 6 hr, then declined gradually to a basal level in 24 hr. Knocking down the expression levels of ZnT1 (located mostly at the plasma membrane) and ZIP8 (present in endosomes and lysosomes) increased and decreased the ZnO-NP-induced elevation of [Zn2+]c, respectively. ZnO-NP treatment reduced the basal levels of reactive oxygen species and Bax/Bcl-2 mRNA ratios; in addition, ZnO-NP decreased the 6-OHDA-induced ROS production, p53 expression, and cell death. These results show that ZnO-NP-induced mild elevation in [Zn2+]c activates beneficial effects in reducing the 6-OHDA-induced cytotoxic effects. Therefore, brain-delivery of ZnO-NP can be regarded as a potential therapy for neurodegenerative diseases., Competing Interests: The authors have declared that no competing interests exist.

Oral mucositis refers to erythematous and ulcerative lesions of oral mucosa during chemo/radiotherapy. Treatment modalities were directed towards reduction in severity of oral mucositis. Zinc plays an important role to retard oxidative processes and is considered as the critical component in wound healing. To compare the efficacy of zinc alone with improvised zinc preparation in reducing the severity of oral mucositis. Improvised zinc was a combination of zinc oxide, amla, tulsi and curcumin at 1% therapeutic concentrations. Seventy-five subjects undergoing chemo/radiotherapy were randomly divided into three groups: Group A (25 subjects) had received topical 5% zinc oxide paste trice daily application after food for entire treatment period, initiated 2 d prior to radiotherapy. Group B (25) received improvised zinc preparations (1%) and instructed to apply same as group A. Group C (25) received standard treatment offered by cancer hospital. All the groups were assessed for oral mucositis using WHO grading system at 7th, 14th, 21st, 28th, 35th day by the oncologist and results were tabulated for statistical analysis. Severity of oral mucositis reduced in zinc and improvised zinc group (p=0.096) when compared with controls with significant p value (0.037). Comparison of improvised zinc preparation (1%) group with only zinc group revealed that severity of overall mucositis though was not significant, was less in improvised zinc group with p value (0.029, 0.013) at 28 and 35 d respectively. Improvised zinc administration during radiation therapy was beneficial in reduction of oral mucositis during cancer treatment.

Reactive oxygen species (ROS)-generating anticancer agents can act through two different mechanisms: (i) elevation of endogenous ROS production in mitochondria, or (ii) formation/delivery of exogenous ROS within cells. However, there is a lack of research on the development of ROS-generating nanosystems that combine endogenous and exogenous ROS to enhance oxidative stress-mediated cancer cell death. Methods: A ROS-generating agent based on polymer-modified zinc peroxide nanoparticles (ZnO 2 NPs) was presented, which simultaneously delivered exogenous H 2 O 2 and Zn 2+ capable of amplifying endogenous ROS production for synergistic cancer therapy. Results: After internalization into tumor cells, ZnO 2 NPs underwent decomposition in response to mild acidic pH, resulting in controlled release of H 2 O 2 and Zn 2+ . Intriguingly, Zn 2+ could increase the production of mitochondrial O 2 · - and H 2 O 2 by inhibiting the electron transport chain, and thus exerted anticancer effect in a synergistic manner with the exogenously released H 2 O 2 to promote cancer cell killing. Furthermore, ZnO 2 NPs were doped with manganese via cation exchange, making them an activatable magnetic resonance imaging contrast agent. Conclusion: This study establishes a ZnO 2 -based theranostic nanoplatform which achieves enhanced oxidative damage to cancer cells by a two-pronged approach of combining endogenous and exogenous ROS., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

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., (© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The predicted global cancer burden is expected to surpass 20 million new cancer cases by 2025. Despite recent advancement in tumor therapy, a successful cancer treatment remains challenging. The emerging field of nanotechnology offers great opportunities for diagnosis, imaging, as well as treatment of cancer. Zinc oxide nanoparticles (ZnO NP) were shown to exert selective cytotoxicity against tumor cells via a yet unknown mechanism, most likely involving the generation of reactive oxygen species (ROS). These nanoparticles are a promising therapeutic opportunity as zinc is a nontoxic trace element and its application in medically-related products is considered to be safe. We could show that ZnO NP can exert cytotoxic effects on several human tumor cell lines. There can be found ZnO NP concentrations which selectively damage tumor cells while human fibroblasts do not sustain lasting damage. Cytotoxicity is attributable to the release of zinc ions from the nanoparticles outside the cells as well as to a direct cell-nanoparticle interaction. This involves uptake of the particles into the tumor cells. With a silica shell the cytotoxicity can be delayed which can help in the future for a safe transport in the blood stream. Cellular damage finally cumulates in apoptotic cell death via zinc overload within 48 h after treatment with ZnO NP. A therapeutical perspective could be the targeted accumulation of ZnO NP at the tumor side to induce local zinc overload that substantially damages the tumor cells with no or low side effects. We suggest further studies to explore the potential of ZnO NP as an innovative anti-tumor agent., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

This study investigated the potential of ZnO-nanoparticle (NP) seed treatments for enhancing Zn nutrition in wheat ( Triticum aestivum). We tested bare, ZnO core Zn 3 (PO 4 ) 2 shell, dextran (DEX)-coated, and dextran sulfate (DEX(SO 4 ))-coated ZnO NPs and ZnSO 4 solution as an ionic control. We measured root and shoot Zn concentrations, lengths, biomasses, and seed germination upon termination of the assay. All ZnO NPs were more effective than ZnSO 4 in increasing tissue Zn concentrations and seedling growth. Exposure to higher concentrations of ZnSO 4 significantly decreased growth and germination rates relative to those of the controls and the ZnO-NP groups, whereas none of the ZnO NPs significantly affected seed germination. Bare and DEX-ZnO NPs increased Zn concentrations in wheat without decreasing growth. The results of this study demonstrated that ZnO NPs can be used as an effective seed treatment to enhance both Zn nutrition and plant growth.

Zinc is an essential trace element, highly important for a well functioning immune system. In case of zinc deficiency, proper immune functions are not ensured thus leading to various diseases. Weaning of pigs from the sow causes stress, increasing susceptibility to infections. Moreover, low feed intake during the first two weeks post-weaning, accompanied by low zinc intake, results in temporary zinc deficiency. Therefore, supporting the immune system by zinc supplementation might improve its function and thereby the pigs' health and well-being. In this study, the immune status of weaned pigs was analyzed under different conditions of zinc supplementation. More precisely, the daily porcine diet was either left unsupplemented (0 ppm), or was supplemented with low (100 ppm), or high (2500 ppm) amounts of additional zinc in the form of zinc oxide (ZnO) (Zn0, Zn100, and Zn2500, respectively). Porcine innate and adaptive immune cells of the different dietary groups were analyzed. Results revealed an improved innate immune capacity, represented by increased phagocytosis and slightly increased oxidative burst in cells from the Zn2500 pigs and Zn100 pigs, respectively. Apart from that, zinc supplementation improved adaptive immunity, as seen by increased numbers of CD3 + T cells as well as increased numbers of CD3 + CD4 + Foxp3 + regulatory T cells, elevated interleukin (IL)-2 production and decreased IL-10 production. Although not significant, supplementing 2500 ppm zinc slightly decreased killing activity of natural killer (NK) cells. Thus, the optimal concentration for zinc supplementation of weaned pigs two weeks post-weaning needs to be further studied, presumably establishing an optimal concentration between 100 ppm and 2500 ppm zinc. Genome comparisons indicate that the porcine genome is more closely related to the human genome than the murine genome is related to the human genome. Therefore, the pig seems to be a suitable organism to study human immunity and diseases. Results obtained in the current study might therefore be transferable to the human immune system., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

The objective of this study was to evaluate the effects of dietary supplementation with zinc oxide nanoparticles (ZnO-NPs) on the performance, egg quality, Zn retention, immunity responses, superoxide dismutase activity (SOD), egg malondialdehyde (MDA) content, and serum parameters in laying hens in the late phase of production. A total of 288 laying hens at 64 weeks of age were randomly assigned to 4 treatments with 6 replicates, and 12 birds within each group. Experimental diets included a corn-soybean meal-based diet (without Zn supplementation) and a basal diet supplemented with 80 mg/kg of Zn-oxide, ZnO-NPs, and Zn-methionine. The results indicated that egg production and egg mass were significantly higher in the Zn-methionine and ZnO-NPs groups (p < .05). Also, eggshell thickness and shell strength increased in the ZnO-NPs group as compared with the other groups (p < .05). Moreover, Zn supplementation decreased egg loss (p < .05). There were significant differences among treatments in Zn deposition in tibiotarsus, liver, pancreas, eggs, and excreta (p < .01). Antibody titre, heterophil (%(, and phytohemagglutinin (PHA) were significantly higher in birds fed with Zn-supplemented diets (p < .05). In treatments supplemented with ZnO-NPs and Zn-methionine, the SOD activity in the liver, pancreas, and plasma was greater as compared with the other treatments (p < .05). The MDA content in eggs was significantly reduced in groups supplemented with Zn (p < .01). Moreover, dietary Zn supplementation significantly affected serum total protein, albumin, glucose, alkaline phosphatase activity, carbonic anhydrase activity, and Zn level (p < .05). In conclusion, this study demonstrated that dietary supplementation with ZnO-NPs can improve the performance of laying hens. Therefore, ZnO-NPs can enhance zinc absorption in the intestine of aged layers and can be a more suitable source of zinc than regular Zn-oxide in diets., (© 2018 Blackwell Verlag GmbH.)

The wide range of applications of ZnO nanoparticles (nano ZnO) in commercial products and the ubiquitous cadmium (Cd) contamination in the natural environment increase the chance of co-existence of nano ZnO with Cd in the surroundings. To investigate the effects of nano ZnO on CdCl 2 -induced hepatotoxicity in mice, the histopathologic changes, metallothionein expression, oxidative stress responses and serum biochemical parameters were determined after oral administration of bulk or nano ZnO and/or CdCl 2 for seven consecutive days. Bulk or nano ZnO had low toxicity in mice. In contrast, CdCl 2 led to significant hepatic oxidative damage, as indicated by hepatic histopathological abnormalities and dysfunction. Bulk and nano ZnO had nearly identical influences on the hepatotoxicity of CdCl 2 in mice. Although co-administration of bulk or nano ZnO with CdCl 2 had a positive cooperative effect on the hepatic uptake of Cd and Zn, both bulk and nano ZnO significantly attenuated CdCl 2 -caused hepatic damage via the reduction of oxidative stress. The increase in metallothionein synthesis and the reduction of Cd-induced perturbation of Zn 2+ homeostasis after co-administration of bulk or nano ZnO with CdCl 2 play two important roles in the protective effect of bulk or nano ZnO on CdCl 2 -caused hepatic oxidative damage.

This study examined the mechanism of toxicity in Arabidopsis thaliana seedlings to zinc oxide nanoparticles (ZnO NPs) and zinc (Zn) ions. We subjected plants to different ZnO NPs and Zn ion concentrations (0, 20, 50, 100 and 200mg/L) and analyzed resulting morphological changes, transcriptional regulation of genes involved in Zn-homeostasis, macro- and microelement homeostasis, as well as auxin regulation. Except for 20mg/L, the fresh weight and primary root length was reduced after exposure to all other concentrations of Zn ion and ZnO NP concentrations. An increase in lateral root formation (19 and 32%) was observed after exposure to 20 and 50mg/L of Zn ions respectively; whereas 20mg/L ZnO NPs treatment triggered a 9% increase in lateral root formation. Both qualitative, using Zynpyr-1 fluorescent probe and quantitative analysis revealed Zn uptake and translocation from roots to shoots after Zn ion exposure. However, ZnO NPs-treated seedlings resulted in no root to shoot translocation and Zn accumulation was mainly located in root tips, primary-lateral root junctions and root- shoot junctions. The macronutrients viz. P (1.34mg/kg DW), K (13.29mg/kg DW), S (1.29mg/kg DW) and micronutrients Cu (0.004mg/kg DW) and Fe (0.345mg/kg DW) contents were highly decreased as a result of exposure to 200mg/L of Zn ions. Similarly, the highest reduction of P (2.30mg/kg DW), K (6.36mg/kg DW), S (2.63mg/kg DW) and Cu (0.004mg/kg DW) was observed after exposure to 200mg/L of ZnO NPs. Gene regulation studies indicated the transcriptional modulation of various genes involved in Zn, macro- and micro nutrient homeostasis as well as hormone regulation. Taken together, it was observed that the mechanism of toxicity of Zn ions and ZnO NPs were different. These findings will help to design safer strategies for the application of ZnO NPs as plant fertilizer without compromising the morphological and nutritional qualities as well as for the future phytoremediation purposes., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Electrical responses of olfactory sensory neurons to odorants were examined in the presence of zinc nanoparticles of various sizes and degrees of oxidation. The zinc nanoparticles were prepared by the underwater electrical discharge method and analyzed by atomic force microscopy and X-ray photoelectron spectroscopy. Small (1.2 ± 0.3 nm) zinc nanoparticles significantly enhanced electrical responses of olfactory neurons to odorants. After oxidation, however, these small zinc nanoparticles were no longer capable of enhancing olfactory responses. Larger zinc oxide nanoparticles (15 nm and 70 nm) also did not modulate responses to odorants. Neither zinc nor zinc oxide nanoparticles produced olfactory responses when added without odorants. The enhancement of odorant responses by small zinc nanoparticles was explained by the creation of olfactory receptor dimers initiated by small zinc nanoparticles. The results of this work will clarify the mechanisms for the initial events in olfaction, as well as to provide new ways to alleviate anosmia related to the loss of olfactory receptors.

For the first time, the influence of different types of atoms (Zn and O) on the antibacterial activities of nanosized ZnO was quantitatively evaluated with the aid of a 3D-printing-manufactured evaluation system. Two different outermost atomic layers were manufactured separately by using an ALD (atomic layer deposition) method. Interestingly, we found that each outermost atomic layer exhibited certain differences against gram-positive or gram-negative bacterial species. Zinc atoms as outermost layer (ZnO-Zn) showed a more pronounced antibacterial effect towards gram-negative E. coli (Escherichia coli), whereas oxygen atoms (ZnO-O) showed a stronger antibacterial activity against gram-positive S. aureus (Staphylococcus aureus). A possible antibacterial mechanism has been comprehensively discussed from different perspectives, including Zn(2+) concentrations, oxygen vacancies, photocatalytic activities and the DNA structural characteristics of different bacterial species., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Zinc oxide (ZnO) nanoparticles may provide a more soluble and plant available source of Zn in Zn fertilizers due to their greater reactivity compared to equivalent micron- or millimetre-sized (bulk) particles. However, the effect of soil on solubility, spatial distribution and speciation of ZnO nanoparticles has not yet been investigated. In this study, we examined the diffusion and solid phase speciation of Zn in an alkaline calcareous soil following application of nanoparticulate and bulk ZnO coated fertilizer products (monoammonium phosphate (MAP) and urea) using laboratory-based x-ray techniques and synchrotron-based μ-x-ray fluorescence (μ-XRF) mapping and absorption fine structure spectroscopy (μ-XAFS). Mapping of the soil-fertilizer reaction zones revealed that most of the applied Zn for all treatments remained on the coated fertilizer granule or close to the point of application after five weeks of incubation in soil. Zinc precipitated mainly as scholzite (CaZn2(PO4)2.2H2O) and zinc ammonium phosphate (Zn(NH4)PO4) species at the surface of MAP granules. These reactions reduced dissolution and diffusion of Zn from the MAP granules. Although Zn remained as zincite (ZnO) at the surface of urea granules, limited diffusion of Zn from ZnO-coated urea granules was also observed for both bulk and nanoparticulate ZnO treatments. This might be due to either the high pH of urea granules, which reduced solubility of Zn, or aggregation (due to high ionic strength) of released ZnO nanoparticles around the granule/point of application. The relative proportion of Zn(OH)2 and ZnCO3 species increased for all Zn treatments with increasing distance from coated MAP and urea granules in the calcareous soil. When coated on macronutrient fertilizers, Zn from ZnO nanoparticles (without surface modifiers) was not more mobile or diffusible compared to bulk forms of ZnO. The results also suggest that risk associated with the presence of ZnO NPs in calcareous soils would be the same as bulk sources of ZnO.

New materials with good antibacterial activity and less toxicity to other species attract numerous research interest. Taking advantage of zinc oxide (ZnO) and graphene oxide (GO), the ZnO/GO composites were prepared by a facile one-pot reaction to achieve superior antibacterial properties without damaging other species. In the composites, ZnO nanoparticles (NPs), with a size of about 4 nm, homogeneously anchored onto GO sheets. The typical bacterium Escherichia coli and HeLa cell were used to evaluate the antibacterial activity and cytotoxicity of the ZnO/GO composites, respectively. The synergistic effects of GO and ZnO NPs led to the superior antibacterial activity of the composites. GO helped the dispersion of ZnO NPs, slowed the dissolution of ZnO, acted as the storage site for the dissolved zinc ions, and enabled the intimate contact of E. coli with ZnO NPs and zinc ions as well. The close contact enhanced the local zinc concentration pitting on the bacterial membrane and the permeability of the bacterial membrane and thus induced bacterial death. In addition, the ZnO/GO composites were found to be much less toxic to HeLa cells, compared to the equivalent concentration of ZnO NPs in the composites. The results indicate that the ZnO/GO composites are promising disinfection materials to be used in surface coatings on various substrates to effectively inhibit bacterial growth, propagation, and survival in medical devices.

The aim of this study was to ascertain whether zinc may improve the repair ability of demineralized dentin. Dentin disks were demineralized by phosphoric acid during 15 s and immersed in artificial saliva, remineralizing solution, a zinc chloride solution and a zinc oxide solution. Dentin specimens were analyzed after 24 h and 1 month of storage. Surface morphology was assessed by atomic force and scanning electron microscopy, mechanical properties were analyzed by nanohardness testing in a TriboIndenter, and chemical changes at the surfaces were determined by X-ray diffraction, Raman and energy-dispersive elemental analyses. After phosphoric acid application, dentin was only partially demineralized. Demineralized dentin was remineralized after 24 h of storage in any of the tested solutions (nanohardness increased and hydroxylapatite formation was detected by Raman). Remineralization was maintained up to 1 month in dentin stored in remineralizing solution, zinc chloride and zinc oxide. Zinc and phosphate were important for hydroxylapatite homeostasis. Scholzite formation was encountered in dentin stored in zinc-containing solutions. Zinc might allow to reach the balance between dentin demineralization and remineralization processes., (© 2014 S. Karger AG, Basel.)

Fungal plant pathogens such as Fusarium graminearum cause severe global economic losses in cereals crops, and current control measures are limited. This work addresses the potential for ZnO nanoparticles (NPs) and biocontrol bacteria to be used in plant fungal control strategies. Growth of F. graminearum was significantly (p = 0.05) inhibited by inclusion of the NPs in a mung bean broth agar and in sand. Suspension in mung bean broth medium modified the surface charge, dissolution, and aggregation state of the ZnO NPs, in comparison to processes occurring in water suspension. The ZnO NPs were significantly more inhibitory to fungal growth than micro-sized particles of ZnO, although both types of particles released similar levels of soluble Zn, indicating size-dependent toxicity of the particles. Zn ions produced dose-dependent inhibition, noticeable at the level of soluble Zn released from NPs after seven-day suspension in medium; inhibitory levels caused acidification of the growth medium. Transfer of fungal inoculum after exposure to the ZnO NPs to fresh medium did not indicate adaptation to the stress because growth was still inhibited by the NPs. The ZnO NPs did not prevent metabolites from a biocontrol bacterium, Pseudomonas chlororaphis O6, from inhibiting Fusarium growth: no synergism was observed in the mung bean agar. Because other studies find that soil amendment with ZnO NPs required high doses for inhibition of plant growth, the findings of pathogen growth control reported in this paper open the possibility of using ZnO NP-based formulations to complement existing strategies for improving crop health in field settings.

High doses of ZnO are used to treat diarrhea in weaning pigs but are also an environmental concern. The mechanism of action of Zn against diarrhea is still not well understood. The amount of solubilized Zn, the relation of Zn with Fe and Cu, and the concentration of these elements in the gastrointestinal tract (GIT) are key data to understanding its mechanism of action and optimize its use. Therefore, we studied the Zn, Fe, and Cu concentrations in the GIT content of unweaned, weaned, and ZnO-treated pigs. Eight litters were used and 3 piglets were selected within each litter. Two piglets from each litter were weaned at 21 d of age and fed a commercial control diet (WCt) or WCt + 2000 mg/kg of Zn as ZnO (WZn). The third pig was kept unweaned (Uw) with the sow. All 24 pigs were killed at 28 d of age, GIT contents were sampled, soluble and insoluble fractions of the content were separated, and Zn, Fe, and Cu concentrations were analyzed. Concentration of Zn increased 3 to 5 fold along the GIT (2 to 10 fold in the soluble fraction) for weaned pigs on WZn compared to WCt and Uw pigs (P < 0.01 in all cases). The proportion of total Zn that was present in the soluble fraction was 4 to 10 folds higher in jejunum, ileum, and cecum of Uw pigs than in those weaned (P < 0.01 in all cases) but was not affected by ZnO treatment. Concentration of Fe in the soluble fraction was higher for Uw pigs compared to weaned pigs along the GIT (P < 0.05 in all cases) even when concentration in total content was lower for Uw pigs in stomach (P = 0.001) and jejunum (P = 0.029). Concentrations of Cu were lower in Uw pigs than in weaned pigs along the GIT (P < 0.05 in all cases). Surprisingly, animals on WZn showed a 5 to 10 fold increase of Cu solubilized in distal parts of the GIT (cecum and colon; P < 0.001) compared to other groups. Differences in Zn, Fe, and Cu concentrations found among treatments will be useful in future studies for understanding mechanism of action of ZnO and optimizing its use in order to avoid environmental concerns.

This experiment was conducted to evaluate the effect of zinc, manganese, and copper sources (inorganic vs. organic) in the diet on laying performance and eggshell quality characteristics. One hundred and eighty Hy-Line W-36 layers at 38 weeks of age were allocated to 36-layer cages of five hens each. Each six cages were randomly assigned to one of the six experimental diets fed from 38 to 53 week of age. In three experimental treatments, the basal diet was supplemented with 65-75-7 or 65-75-7 or 40-40-7 mg/kg of Zn, Mn, and Cu, respectively, from their oxide or sulfate sources. Three other groups were fed diets supplemented with 20-20-3.5 or 40-40-7.5 or 60-60-10.5 mg/kg of organic forms of Zn, Mn, and Cu, respectively. Dietary treatments significantly did affect feed intake (P < 0.001), feed conversion ratio (P < 0.001) and percentage of broken eggs (P < 0.05). Substitution of Zn and Mn oxides (65 and 75 mg kg(-1), respectively) with equal amounts of their sulfate forms significantly improved feed intake, feed conversion ratio, percentage of broken eggs, and Haugh Unit (P < 0.05). In addition, laying hens maintained their performance when substitution of Zn and Mn oxides and Cu sulfate (65, 75, and 7 mg kg(-1), respectively) reduced up to 20, 20, and 3.5 mg kg(-1) by amino acid complexes of the microelements. The results showed that a corn-soybean diet supplemented with the organic forms of Zn, Mn, and Cu at a dosage 50% to 75% lower than NRC recommendation is sufficient to maintain laying performance and can improve eggshell and albumen qualities of the egg in laying hens.

Aim: To investigate the efficacy of intra-ruminal Zn boluses as aids in providing protection from natural Pithomyces chartarum challenge in calves., Methods: Sixty-two calves (mean weight 187 (SEM 3.25) kg) were divided into three groups. Commencing on Day 0, they received either a proprietary bolus containing 83% ZnO (ZnO group), a prototype Zn bolus containing 88% elemental Zn (Zn group), or remained untreated (Control group). Concentrations of Zn in serum and faeces were measured weekly between Days 6 and 34, activities of gamma-glutamyl transferase (GGT) in serum on Days -8, 20, 34 and 41, and faecal spore counts between Days 13 and 41., Results: Between Days 6 and 34, mean concentrations of Zn in serum increased in both Zn treatment groups compared with Controls (p<0.001), but were lower in Zn than ZnO animals between Days 6 and 28 (p=0.05). Concentrations of Zn in faeces were increased in both groups following treatment with Zn. Mean concentrations of Zn in faeces in ZnO animals was higher than Zn animals on Days 13 and 20 (p<0.001), but decreased by Day 34, whereas for Zn animals they were still elevated on Day 34. Faecal spore counts were 354,000 and 183,000 on Days 13 and 20, respectively, 610,500 on Day 28, and 115,500 spores/g on Day 34. There were no clinical signs of facial eczema, but based on the activities of GGT on Day 41, 17/20 (85%) Controls were moderately or severely affected (GGT >250 IU/L) compared with 1/21 (5%) ZnO and 3/21 (14%) Zn animals. Mean activities of GGT on Day 41 for ZnO and Zn animals were not different (35 (95% CI=23-54) and 54 (95% CI=32-92) IU/L, respectively; p=0.18), but were below those of the Controls (502 (95% CI=296-850) IU/L), confirming efficacy of both bolus treatments. In both ZnO and Zn animals, there was no significant relationship between concentration of Zn in serum and activity of GGT, but in Zn animals there was a significant relationship between the concentration of Zn in faeces and activity of GGT 21 days later. The regression equation y=2.136-0.002197x (where y is log10GGT activity, and x the concentration of Zn in faeces) provided an estimate of the threshold level of concentration of Zn in faeces., Conclusion: The study confirmed efficacy of elemental Zn boluses in providing protection from natural P. chartarum challenge in young cattle.

Aim: To investigate the efficacy of intra-ruminal Zn boluses as aids in providing protection from natural Pithomyces chartarum challenge in sheep., Methods: Seventy-two adult sheep (mean weight 59 (SEM 0.5) kg) were divided into four groups. Commencing on Day 0, they received either a proprietary bolus containing 67 g ZnO (equivalent to 54 g Zn) (ZnO group), two different levels of elemental Zn (81 and 108 g) delivered in boluses each containing 27 g Zn (Zn81 and Zn108 groups, respectively), or remained untreated (control). Concentrations of Zn in serum, activities of gamma-glutamyl transferase (GGT) in serum, and spore counts on pasture were measured weekly from Day -6, and concentrations of Zn in faeces weekly from Day 21, until Day 77., Results: Mean concentrations of Zn in serum between Days 14 and 42 were significantly higher in ZnO animals (15.4 (SEM 0.70) micromol/L) than the other groups. Mean concentrations in Zn108 animals (11.1 (SEM 0.26) micromol/L) were significantly higher than controls, but there were no differences between Zn81 and the controls (9.9 (SEM 0.20) and 9.4 (SEM 0.26) micromol/L, respectively). Between Days 21 and 49, there was no significant difference in mean concentrations of Zn in faeces between ZnO and Zn81 animals (307 (SEM 28) and 281 (SEM 29) mg/kg fresh weight (FW), respectively), but concentrations were significantly higher in Zn108 animals (500 (SEM 40) mg/kg FW). Spore counts exceeded 70,000/g on Days 14, 28, 49, 56 and 63 but there were no clinical signs of facial eczema. In controls, activities of GGT were unchanged until Day 21, then increased to 637 IU/L at Day 70; for ZnO animals, activities remained <75 IU/L until Day 14, then increased to 200 IU/L at Day 70; for Zn81 and Zn108, they remained <75 IU/L until Day 35, and then increased at Day 70 to 369 IU/L and 293 IU/L, respectively. From Day 56 activities were significantly lower in all treated groups compared with controls, but there was no significant difference between the three Zn bolus treatments. There were significant negative correlations between activities of GGT and concentrations of Zn in serum in Zn108 animals, and with concentrations of Zn in faeces for both Zn81 and Zn108 groups., Conclusion: Elemental Zn boluses can reduce activities of GGT associated with elevated spore counts. The association between concentrations of Zn in faeces and activities of GGT suggests that a minimum concentration of Zn in the gastrointestinal tract may be important in providing protection against sporidesmin.

To decrease the side effects of the existing copper-bearing intrauterine devices, the zinc/low-density polyethylene (Zn/LDPE) nanocomposite and zinc-oxide/low-density polyethylene (ZnO/LDPE) nanocomposite have been developed in our research for intrauterine devices (IUDs). In this study, the influences of preparation methods of nanocomposites and particle sizes of zinc and zinc oxide on Zn(2+) release from composites incubated in simulated uterine solution were investigated. All release profiles are biphasic: an initial rapid release phase is followed by a near zero-order release period. Zn(2+) release rates of nanocomposites prepared by compressing moulding are higher than those of the nanocomposites prepared by hot-melt extrusing. Compared with Zn(2+) release from the microcomposites, the release profiles of the nanocomposites exhibit a sharp decrease in Zn(2+) release rate in the first 18 days, an early onset of the zero-order release period and a high release rate of Zn(2+) at the later stage. The microstructure of the Zn/LDPE sample and the ZnO/LDPE sample after being incubated for 200 days was characterized by SEM, XRD and EDX techniques. The results show that the dissolution depth of ZnO/LDPE nanocomposite is about 60 mum. Lots of pores were formed on the surface of the Zn/LDPE sample and ZnO/LDPE sample, indicating that these pores can provide channels for the dissolution of nanoparticles in the matrix. The undesirable deposits that are composed of ZnO are only detected on the surface of Zn/LDPE nanocomposite, which may increase the risk of side effects associated with IUDs. It can be expected that ZnO/LDPE nanocomposite is more suitable for IUDs than Zn/LDPE nanocomposite.

Two 28-d randomized complete block design experiments were conducted to evaluate the effects of concentrations and sources of Zn on growth performance of nursery pigs. Seven stations participated in Exp. 1, which evaluated the efficacy of replacing 2,500 ppm of Zn from ZnO with 125, 250, or 500 ppm of Zn from Zn methionine. A control diet with 125 ppm of supplemental Zn was included at all stations. A total of 615 pigs were used in 26 replicates. Average weaning age was 20.6 d and the average initial BW was 6.3 kg. There were no differences in any growth response among the three supplemental Zn methionine levels fed in Exp. 1. Zinc supplementation from Zn methionine improved ADG compared with the control during all phases (P < 0.05), due primarily to an increase in ADFI. Pigs fed 2,500 ppm of Zn from ZnO gained faster (P < 0.01) than those fed the control diet during all phases, and faster (P < 0.05) than those fed supplemental Zn from Zn methionine for the 28-d experiment. Differences in gain were again due mainly to differences in feed intake. A second experiment compared five sources of supplemental organic Zn (500 ppm of Zn) with 500 and 2,000 ppm supplemental Zn from ZnO and a control (140 ppm total Zn). Six stations used a total of 624 pigs, with an average weaning age of 20.4 d and averaging 6.2 kg BW in 15 replicates. Pigs fed 2,000 ppm of Zn from ZnO gained faster (P < 0.05) than pigs fed the control or any of the 500 ppm of Zn treatments (ZnO or organic Zn). Pigs fed the 2,000 ppm of Zn from ZnO also consumed more feed than those receiving 500 ppm of Zn from ZnO or from any of the organic Zn sources (P < 0.05). Organic sources of Zn did not improve gain, feed intake, or feed efficiency beyond that achieved with the control diet. Supplemental Zn at a concentration of 500 ppm, whether in the form of the oxide or in an organic form, was not as efficacious for improved ADG as 2,000 to 2,500 ppm of Zn from ZnO.

Feeding pharmacological zinc (Zn) to weaned pigs improves growth, and dietary phytase improves P and Zn availability. Metallothionein (MT) increases in the duodenum, kidney, and liver of pigs fed 1000 mg Zn/kg with phytase or 2000 mg Zn/kg with or without phytase when fed for 14 d postweaning. The goal of this study was to determine the effects of feeding pharmacological Zn and phytase on tissue minerals, MT, mineral excretion, and apparent retention. Twenty-four newly weaned pigs (20 d; 7.2 kg) were individually fed twice daily, a basal diet supplemented with 0, 1000, or 4000 mg Zn/kg as Zn oxide, without or with phytase (500 phytase units [FTU]/kg) for 14 d, followed by a basal diet (100 mg Zn/kg) without phytase for 7 d. Pigs fed 4000 mg Zn/kg without phytase had higher (p=0.01) plasma, hepatic, renal Zn, renal Cu, and hepatic, renal, and jejunal MT than pigs fed the basal diet or 1000 mg Zn/kg. Duodenal MT was higher (p=0.0001) in pigs fed 1000 and 4000 mg Zn/kg than in pigs fed the basal diet. In pigs fed 1000 and 4000 mg Zn/kg, Zn loading occurred during the first 11 d of supplementation; by d 14, excess Zn was being excreted in the feces.

Two experiments were conducted to evaluate the effects of Cu and Zn source on performance, morbidity, and humoral immune response in lightweight, newly received beef heifers. A 2 x 2 factorial arrangement of treatments was used in both experiments, with either a sulfate or a polysaccharide mineral complex (SQM) source of both Cu and Zn as the factors. Supplemental Cu and Zn were included in the receiving diet at concentrations designed to provide 10 mg of Cu/kg and 75 mg of Zn/kg (DM basis). In Exp. 1, 219 newly received beef heifers (British x Continental, average initial BW = 208 kg) were given ad libitum access to a 65% concentrate diet for 35 d to determine treatment effects on DMI, ADG, G:F, and bovine respiratory disease (BRD) morbidity. In Exp. 2, 24 heifers (average initial BW = 272 kg) were fed a diet with no supplemental Cu or Zn for 35 d, followed by fasting-refeeding-fasting stress, after which the same treatment diets used in Exp. 1 were fed for 21 d to examine the effects on humoral immune response (plasma IgG titer determined by ELISA on d 7, 14, and 21) to an ovalbumin (OVA) vaccine given on d 0 and 14. Copper source x Zn source interactions were not detected in either experiment. In Exp. 1, neither Cu nor Zn source affected (P > 0.10) DMI, ADG, G:F, or BRD morbidity. In Exp. 2, d 14 (P = 0.02) and 21 (P = 0.06) OVA titers were greater for heifers that received SQM Zn compared with heifers receiving ZnSO4, but heifers receiving CuSO4 had greater OVA titers than did heifers on the SQM Cu treatment on d 14 (P = 0.01) and 21 (P = 0.001). In summary, neither supplemental Cu nor Zn source affected performance or morbidity of lightweight, newly received heifers; however, source of both Cu or Zn affected the humoral immune response to OVA, although source effects were not consistent for the two minerals.

Sixty Angus and Angus x Hereford steers (246 kg initial BW) were used to determine the effects of Zn level and source on performance, immune response, and carcass characteristics of growing and finishing steers. Treatments consisted of 1) control (no supplemental Zn), 2) ZnO, 3) Zn proteinate-A (ZnProt-A, 10% Zn), and 4) ZnProt-B (15% Zn). Treatments 2, 3, and 4 supplied 25 mg of supplemental Zn/kg diet. Steers were individually fed a corn silage-based diet during the 84-d growing phase and a high corn diet during the finishing phase. Cell-mediated and humoral immune response measurements were obtained between d 67 and 74 of the growing phase. Equal number of steers per treatment were slaughtered after receiving the finishing diets for 84 or 112 d. Performance and carcass measurements were similar in steers fed the two ZnProt sources. Zinc supplementation, regardless of source, increased (P < 0.05) ADG during the growing phase. In the finishing phase, ADG (P = 0.10) and gain/feed (P = 0.07) tended to be higher for steers fed ZnProt compared with those supplemented with ZnO. Gain and feed efficiency were similar for control and ZnO-supplemented steers during the finishing phase. Steers fed ZnProt had heavier (P < 0.05) hot carcass weights and slightly higher (P < 0.05) dressing percentages than those in the control or ZnO treatments. Quality grade, yield grade, marbling, and backfat were increased by Zn supplementation, but were not affected by Zn source. In vitro response of lymphocytes to mitogen stimulation and in vivo swelling response following intradermal injection of phytohemagglutinin were not affected by Zn level or source. Humoral immune response following vaccination with infectious bovine rhinotracheitis also was not affected by treatment. Soluble concentrations of Zn in ruminal fluid were higher (P < 0.05) in steers fed ZnProt compared to ZnO steers. Results indicate that ZnProt may improve performance of finishing steers above that observed with inorganic Zn supplementation.

Four trials were conducted to examine concentration of zinc in tissues and performance of pigs fed high levels of Zn from ZnO, Zn-methionine, Zn-lysine, or ZnSO4. In Trials 1 (n = 80, 28 d of age, 7.5 kg BW), 2 (n = 80, 26 d of age, 7.1 kg BW), and 3 (n = 70, 23 d of age, 5.3 kg BW), pigs were assigned either to a control diet containing 105 mg/kg of Zn and 15 mg/kg of Cu or to supplemental dietary treatments of 3,000, 2,000, or 1,000 mg of Zn/kg of diet. In all three trials, dietary sources were ZnO, Zn-methionine, Zn-lysine, or ZnSO4. The trials lasted 2 wk. In Trial 1, performance of pigs generally was not improved by feeding 3,000 mg of Zn/kg from any of the Zn sources. Serum, liver, and rib Zn concentrations (P < .01) and liver Zn concentrations (P < .05) were greater for pigs fed the high Zn diets. In Trial 2, feeding high Zn did not affect overall performance. Pigs fed the high Zn diets had greater (P < .01) serum, liver, kidney, and rib Zn concentrations. In Trial 3, there were no differences (P > .10) in ADG or ADFI, but serum and liver Zn concentrations were greater (P < .01 and .05, respectively) for pigs fed high Zn diets. Within Zn sources, serum and liver concentrations of Zn were greater (P < .05) for pigs fed ZnSO4 rather than ZnO in Trials 1 and 2. In Trial 4 (n = 72, 7.1 kg), 25-d-old pigs fed diets containing 3,000 mg/kg of Zn from feed-grade ZnSO4, reagent-grade ZnSO4, or feed-grade ZnO in a 4-wk growth trial had similar ADG and ADFI, but the gain:feed ratio was lower (P < .05) for pigs fed the reagent-grade ZnSO4. Serum, liver, and kidney Zn concentrations were lower (P < .05) for pigs fed the ZnO diet after wk 2 than for pigs fed the ZnSO4 diets, but no differences (P > .10) were observed at the end of wk 4. In summary, performance was not enhanced by feeding pharmacological levels of zinc after weaning, although serum and tissue Zn concentrations were increased. When compared with the bioavailability of Zn in ZnSO4, the bioavailability of Zn was lowest for ZnO and intermediate for Zn-lysine and Zn-methionine.

Noninvasive aspergillosis of the maxillary sinus is frequently associated with extrusion of root canal cements into the sinus, and it has been suggested that zinc oxide-based materials might promote infection because zinc is a growth factor for Aspergillus sp. To investigate this possibility pure zinc oxide-eugenol cement and five other cements were tested for antifungal activity against five strains of Aspergillus fumigatus, one strain of A. niger, and one strain of A. flavus by zone inhibition and by spectrophotometric measurement of growth rates at various zinc concentrations. All cements had antifungal activity. Eugenol-containing materials had the most activity, but this activity was reduced with mixing and setting. No growth enhancement attributable to zinc was detected by either method. To determine whether contaminated materials might introduce spores into the sinus, 63 samples taken from one clinic were cultured. Aspergillus sp. was isolated from two.

The bioavailability of zinc-methionine (ZnMET) was compared to that of feed-grade ZnSO4.H2O using three different diets: purified (crystalline amino acid [AA]), semipurified (soy isolate), and complex (corn-soybean [C-SBM]) diet. With the Zn-deficient purified or semipurified diet, weight gain and tibia Zn responded linearly to both ZnSO4.H2O and ZnMET supplementation. Common-intercept, multiple linear regression indicated differences in Zn bioavailability between ZnMET and ZnSO4.H2O for both diets as indicated by bone Zn. With the ZnSO4.H2O standard set at 100%, bioavailability of Zn from ZnMET was 117% (P less than .05) in the AA diet and 177% (P less than .01) in the soy isolate diet. The ZnMET was also compared to ZnSO4.H2O in a C-SBM diet containing 117 mg of Zn/kg. When high levels of Zn were added to this diet (0, 250, 500, and 750 mg/kg of supplemental Zn), consistent tissue Zn responses did not occur beyond the first increment. Addition of lower levels of supplemental Zn (0, 5, 10, 20, 30, 40 and 50 mg/kg) to a Zn-unsupplemented C-SBM basal diet (45 mg/kg of Zn), however, resulted in a broken-line, two-slope response in tibia Zn for both ZnMET and ZnSO4.H2O. Inflection points occurred at 60 and 54 mg of Zn/kg of diet for ZnSO4.H2O and ZnMET, respectively. The ratio of slopes (ZnMET:ZnSO4.H2O) below the inflection points was 206% (P less than .01), indicating that Zn was considerably more bioavailable in ZnMET than in ZnSO4.H2O for chicks consuming C-SBM diets. When feed-grade ZnO was compared to feed-grade ZnSO4.H2O in chicks consuming C-SBM diets, bone Zn slopes below the respective inflection points indicated that Zn was 61% bioavailable in ZnO relative to ZnSO4.H2O.

Three experiments were conducted using feedlot steers in a randomized block design to determine the effect of zinc methionine (ZnMet) and zinc oxide (Exp. 3) on feed intake (DMI), rectal temperature, and serum mineral concentrations of feedlot cattle challenged with infectious bovine rhinotracheitis virus (IBRV). All the steers used were seronegative to IBRV. Steers were adapted for 7 d to their respective diets and challenged with 3.7 x 10(5) plaque forming units of IRBV on d 0 of each experiment. Live BW, rectal temperature, and individual daily DMI were recorded for 14 d. Blood samples were taken on d 0, 7, and 14. In Exp. 1, daily DMI of the control steers (Zn = 31 ppm) decreased 50% compared with 15% in the ZnMet (Zn = 90 ppm) steers 3 d after IBRV challenge. By d 6, the ZnMet steers had regained their pretrial mean daily DMI, but the control steers took 11 d. The ZnMet steers had lower (P less than .05) mean rectal temperature than the control steers on d 7 and 12. In Exp. 2, the control (Zn = 35 ppm) steers had lower (P less than .05) daily DMI on d 8 to 12 than the ZnMet (Zn = 89 ppm) steers. In Exp. 3, the mean decrease in daily DMI tended to be more rapid in the ZnO steers than in the control and ZnMet steers. All steers had the lowest daily DMI on d 5 and 6, coinciding with the highest rectal temperature. Serum Zn, P, and Mg concentrations decreased and serum Cu increased in all steers after infection. These data suggest that dietary Zn enhanced the recovery rate of IBRV-stressed cattle.

The effect of zinc oxide on S. aureus (209 P) was studied in steel net tissue cages implanted subcutaneously in guinea pigs and rabbits. Zinc oxide installed in the tissue cages created high, sustained concentrations of zinc in the cage fluid throughout the study. In a concentration of 22 mmol/l zinc oxide reduced viable counts in tissue cage fluid inoculated with S. aureus. No deleterious effect was observed on polymorphonuclear cell function.

Measurement of mechanics of respiration in guinea pigs was used to assess the irritant potency of zinc oxide and sulfur dioxide mixed under different conditions of temperature and humidity. Concentrations were 1-2 mg/m3 zinc oxide and 1 ppm sulfur dioxide. Dry conditions of mixing (Chamber RH 30%) either at 24 degrees C in the exposure chamber or at 480 degrees C in a dry furnace gave a biological response which could be completely accounted for by responses to zinc oxide and/or sulfur dioxide alone. Chemical examination of the aerosols did not indicate the formation of particulate sulfur species. Zinc oxide and sulfur dioxide mixed dry at 480 degrees C and fed into the exposure chamber at 80% RH reacted to produce an irritant aerosol as evidenced by a rapid increase to levels 29% above control; reversal was rapid when exposure ended. Chemical studies indicated the presence of sulfite on these aerosols. Addition of water vapor to the furnace during mixing at 480 degrees C produced a different irritant aerosol. The resistance rose slowly to 19% above control values and remained elevated during the post-exposure hour. Chemical studies indicated the presence of sulfate, sulfite, and adsorbed sulfur trioxide on these aerosols.

The effects of the addition of Zn as ZnO to diets to induce molt were evaluated against a fasted control. Experiment 1 involved 315 Leghorn hens, 15 months old, randomly distributed among five treatments, each replicated seven times with 9 hens per replicate. Hens fasted for 10 days were compared with hens fed diets to which ZnO was added at 10,000, 5,000, or 2,500 ppm for 7, 14, or 21 days. No significant differences were observed among treatments for days to return to 50% production, hen-day and hen-housed production, egg weight, grams egg per hen-day, grams of feed per gram egg, mortality, or Haugh units during the 22-week experimental period. Experiment 2 involved 420 Leghorn hens, 18 months old, randomly distributed among five treatments, each replicated seven times with 12 hens per replicate. Treatments involved fasting for 10 days or feeding diets with 10,000, 5,000, or 2,500 ppm ZnO fed for 7, 14, or 21 days. Hens fasted and hens fed diets with 10,000 ppm ZnO at the start of the experiment ceased production in significantly less time (4.6 to 6 days) than hens fed 5,000 ppm ZnO (14.3 to 14.9 days); however, days to return to 50% production from the start of the experiment did not differ among treatments. Feed consumption and feed cost per hen day during molt were lowest (P less than .05) in the fasted hens.(ABSTRACT TRUNCATED AT 250 WORDS)

IRM has been shown to be superior to conventional ZnOE cements. This study is a biotechnical investigation of IRM's effect on the dental pulp with respect to its sealing capacity. Enamel-dentin test bodies with IRM fillings were used in the in vitro part, where insufficiencies in sealing were detected with compressed air. The in vivo part included 44 buccal cavities in intact premolars. In teeth in which the material effect of IRM was tested, the IRM fillings were sealed off from the saliva by acid etch and composite resin. The observation intervals were 1, 7 and 28 days. Histologic changes such as capillary dilatations and presence of inflammatory cells in the pulp adjacent to the dentinal tubules involved in the cavity preparation were registered. The in vitro test showed no leakage in five cases out of six. After extreme temperature cycling, the leakage was comparable with that of zinc-containing amalgam of traditional alloy. The pulpal changes were mild and mainly ascribed to the material effect of IRM, since no evidence was found of leakage of biologic importance.

Zinc pyrithione introduced into cultures of rapidly proliferating NCTC 2544 human skin epithelial cells and normal human skin fibroblasts had a rapid cytotoxic effect even at very low concentrations (0.1-0.5 microgram/ml); there was no dose-dependent suppression of cell proliferation and no apparent interference with mitosis. Sodium pyrithione had a similar effect. Zinc oxide and zinc sulphate were at least 100 times better tolerated than zinc pyrithione, but no stimulatory effect on cell growth was detected with low concentrations of either compound. These results suggest that zinc pyrithione's action against dandruff is more likely to arise from a non-specific toxicity for epidermal cells than by an anti-mitotic effect or by remedying a local zinc deficiency.

1. In Expt 1, the effects on laying hens of diets supplemented with zinc oxide providing up to 20 g added zinc/kg were compared. In Expt 2 the diets contained up to 6 g added Zn/kg. 2. In both experiments, food intake, body-weight, egg number, and liver, oviduct and ovary weights/kg body-weight were significantly reduced by added ZnO; gizzard weight/kg body-weight was significantly increased. In Expt 2, pancreas weight was significantly reduced by added ZnO. 3. Liver, kidney and pancreatic Zn and iron concentrations were significantly elevated in both experiments. 4. In both experiments, liver, kidneys and pancreatic copper concentrations gave quadratic responses to added ZnO.