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Biodisponibilidade de fontes orgânicas e inorgânicas de zinco em ovinos; Bioavailability of organic and inorganic zinc sources in sheep

VILELA, F.G.; ZANETTI, M.A.; NETTO, A. Saran; FREITAS JUNIOR, J.E.; YOSHIKAWA, C.Y.C.
Fonte: Universidade Federal de Minas Gerais, Escola de Veterinária Publicador: Universidade Federal de Minas Gerais, Escola de Veterinária
Tipo: Artigo de Revista Científica
POR
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Compararam-se os efeitos de diferentes fontes e doses de zinco na dieta de ovinos Santa Inês sobre os níveis de zinco plasmático e de fosfatase alcalina. Foram utilizados 40 cordeiros, recém-desmamados, com média de peso de 18,4kg, distribuídos em 10 tratamentos: 1- dieta basal sem suplementação de zinco; 2- dieta basal + 200mg de Zn/kg de MS na forma de óxido de zinco; 3- dieta basal + 400mg de Zn/kg de MS na forma de óxido de zinco; 4- dieta basal + 600mg de Zn/kg de MS na forma de óxido de zinco; 5- dieta basal + 200mg de Zn/kg de MS na forma de zinco aminoácido; 6- dieta basal + 400mg de Zn/kg de MS na forma de zinco aminoácido; 7- dieta basal + 600mg de Zn/kg de MS na forma de zinco aminoácido; 8- dieta basal + 200mg de Zn/kg de MS na forma de zinco proteinato; 9- dieta basal + 400mg de Zn/kg de MS na forma de zinco proteinato; 10- dieta basal + 600mg de Zn/kg de MS na forma de zinco proteinato. A cada 28 dias, os animais foram pesados e tiveram seu sangue colhido para análise de zinco (Zn), análise de fosfatase alcalina e análises de imunoglobulinas G (IgG) e M (IgM). No final do experimento, foram coletadas amostras de fígado para estudo dos níveis de zinco hepático. Não houve diferença entre tratamentos nos níveis de fosfatase alcalina e de zinco hepático...

Proteína láctea e zinco suplementar em dietas de leitões recém-desmamados; Milk protein and supplemental zinc in weaned pigs diets

Tse, Marcos Livio Panhoza
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 21/08/2007 PT
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Foram utilizados 120 leitões (60 em cada experimento) da genética Dalland, desmamados aos 21 dias de idade e pesos médios iniciais de 5,43 kg ± 0,46 (Exp. 1) e 5,81 kg ± 0,54 (Exp. 2) com o objetivo de avaliar a presença de proteína láctea ou zinco suplementar (Znaminoácidos) sobre o desempenho, concentrações sanguíneas de IGF-I, GH, zinco, morfologia intestinal e peso relativo do fígado e intestino delgado dos leitões. O delineamento experimental foi o de blocos casualisados, com 14 dias (Exp.1) e 28 dias (Exp.2) de duração em um fatorial 2 x 2 (proteína láctea e zinco suplementar): T1 = Dieta basal constituída de milho e farelo de soja (DB), com proteína láctea (PL) e com Zn suplementar (2000 ppm de zinco - ZnO + 250 ppm de zinco ? Znaminoácidos); T2 = DB com PL e sem zinco suplementar; T3 = DB sem PL e com zinco suplementar; T4 = DB sem PL e sem zinco suplementar. No Exp.1, o zinco suplementar, proporcionou melhor conversão alimentar (CA) para a fase de 1 a 7 dias (P<0,04) e para a fase de 1 a 14 dias, proporcionou maior peso aos 14 dias (P14) (P<0,06) e maior ganho de peso diário (GPD) (P<0,05). A PL, proporcionou aos animais, menor CA para as fases de 1 a 7 dias (P<0,001) e de 1 a 14 dias (P<0,02)...

Estado nutricional relativo ao zinco de crianças com fissura labiopalatina; Nutritional status of zinc in children with cleft lip palate

Mattos, Camila Frazão Nogueira de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 12/11/2010 PT
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A Fissura Labiopalatina é uma doença multifatorial que tem interferência sobre a qualidade da alimentação da criança, visto que na maioria das vezes os pacientes têm dificuldades de mastigação e deglutição. O zinco está envolvido em diversos processos fisiológicos, tem importante relação com mecanismos antioxidantes, imunitários, replicação celular e de transcrição protéica. De acordo com a Organização Mundial de Saúde, o zinco é o micronutriente mais importante para o desenvolvimento corporal e cognitivo da criança. Considerando a interferência da Fissura Labiopalatina sobre a qualidade da alimentação, e a importância do zinco para o desenvolvimento da criança, este estudo se propôs a avaliar o estado nutricional relativo ao zinco de crianças de 6 a 10 anos com Fissura Labiopalatina atendidas no Centro de Atendimento Integrado ao Fissurado Labiopalatino de Curitiba - PR. Foram dosadas as concentrações de zinco plasmático, eritrocitário e urinário. A quantidade de zinco dietético foi avaliada por meio dos métodos de recordatório de 24h e três registros alimentares. Foram avaliados peso e estatura, como dados antropométricos, e comparados ao escore Z. O estudo foi do tipo casocontrole. A concentração média de zinco plasmático...

Avaliação de fontes, absorção foliar e translocação de zinco (68Zn) em laranjeiras; Sources evaluation, foliar uptake and zinc translocation (68Zn) in Orange

Guedes, Elaine Maria Silva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/09/2012 PT
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Os estudos de adubação com zinco foliar em citros desenvolvidos no Brasil são na maioria das vezes limitados às informações das quantidades dos nutrientes absorvidos pelas folhas, porém o transporte do zinco das folhas para outras partes das plantas ainda precisa ser esclarecido. A maioria das investigações sobre tal assunto é vasta de resultados conflitantes. Em vista disso, o uso da técnica com isótopos estáveis é uma ferramenta viável para auxiliar na determinação direta da absorção e translocação de zinco aplicado via foliar no citros. O presente estudo tem como objetivos determinar (i) os teores de zinco nas folhas durante três dias após a pulverização; na fase de floração e frutificação do citros: (ii) teores e acúmulos de zinco nas folhas e frutos; (iii) concentração de zinco nos pluviolixiviados das folhas; (v) absorção e translocação do zinco proveniente das fontes nas folhas; (vi) translocação do zinco proveniente das fontes nos frutos; (vi) concentrações de zinco nos pluviolixiviados das folhas provenientes das fontes.Foram conduzidos dois experimentos na Estação Experimental de Citricultura de Bebedouro-SP. No primeiro experimento foram avalidas cinco fontes foliares de zinco, EDTA...

THE ASSESSMENT OF ZINC STATUS BY THE ZINC TOLERANCE-TEST IN THYROID-DISEASE

Pimenta, W. P.; Brandaoneto, J.; Curi, P. R.
Fonte: Dustri-verlag Dr Karl Feistle Publicador: Dustri-verlag Dr Karl Feistle
Tipo: Artigo de Revista Científica Formato: 34-37
ENG
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Zinc status was evaluated in 12 hyperthyroid and in 7 hypothyroid patients in comparison with 8 euthyroid individuals by the oral zinc tolerance test and by the determination of urinary zinc excretion. Hyperthyroid patients presented a basal serum concentration similar to that of euthyroid individuals but greater urinary zinc excretion, indicating the occurrence of zinc depletion from tissues to the blood stream caused by the catabolism inherent in the hyperthyroid state. Hyperthyroidism also caused lower zinc assimilation by tissues after zinc ingestion. Hypothyroid individuals present lower basal zinc levels in serum than euthyroid and hyperthyroid individuals and urinary zinc excretion similar to that of euthyroid individuals. No changes in the parameters measured were observed after zinc load, suggesting reduced or delayed intestinal absorption and zinc assimilation by tissues. The present data are indicative of zinc deficiency, the lower intestinal zinc absorption probably being one of the contributing factors.

Optimum zinc supplementation level in Nile tilapia Oreochromis niloticus juveniles diets

Sa, MVDE; Pezzato, L. E.; Lima, MMBF; Padilha, P. D.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 385-401
ENG
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The present study was designed to determine the optimum dietary zinc supplementation to Nile tilapia juveniles (13.3 +/- 1.13 g), by using vegetable-based diets supplemented with increasing levels of zinc from commercial-grade zinc sulfate monohydrate, a previously determined zinc source of higher bioavailability. The basal diet was supplemented with 25, 50, 100, 150, 200, 300, or 400 mg/kg Zn. The experiment was conducted in forty 250-l tanks arranged in a recirculating water system. The experimental period was divided in two phases. For the first 10-week experimental phase, fish were fed satiation diets supplemented with increasing levels of zinc. For the second 5-week experimental phase, fish that were fed diets supplemented with 0-300 mg/kg Zn during the first phase were fed the 400 mg/kg Zn-supplemented diet; fish fed the diet supplemented with 400 mg/kg Zn (first phase) were fed the nonzinc-supplemented diet (second phase). Broken-line analysis showed that the optimum dietary zinc supplementation ((ZnSO4H2O)-H-.) to Nile tilapia juveniles, using weight gain and bone zinc saturation as response criteria, was 44.50 and 79.51 mg/kg Zn, respectively. When challenged by a zinc-deficient diet, tilapia mobilized stored bone zinc to preserve its zinc status. By considering that bone zinc saturation is a more accurate response criterion than weight gain...

RENAL EXCRETION OF ZINC IN NORMAL INDIVIDUALS DURING ZINC TOLERANCE-TEST AND GLUCOSE-TOLERANCE TEST

Brandaoneto, J.; Shuhama, T.; Pimenta, W. P.; Piesco, R. V.; Castro, AVB; Mazeto, GMGS; Chung, J. S.; Franco, RJS; Curi, P. R.
Fonte: Dustri-verlag Dr Karl Feistle Publicador: Dustri-verlag Dr Karl Feistle
Tipo: Artigo de Revista Científica Formato: 62-67
ENG
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The urinary excretion, renal clearance, and tubular reabsorption of zinc were investigated in 30 adult healthy subjects under basal conditions and during the zinc and glucose tolerance tests. After a 12h overnight fast, each subject was submitted to renal clearance of zinc. The procedures were performed between 8.00 and 12.00 a.m., after emptying the bladder and ingestion of 4 ml deionized water/kg body weight at 8.00 a.m. The first urine sample was collected at 10.00 a.m., and the second at 12.00 a.m. A dose of 110 mg ZnSO4.7H(2)O was administered orally to each subject, diluted in 20 mi deionized water, at time 0 min. Blood samples were collected from an antecubital vein at times -30, 0, and 30 min and at 30 min intervals up to 240 min. Glucose was administered intravenously (0.5 ml 50%/kg body weight) during the first 3 min of the test, and blood samples were collected from an unconstricted, contralateral, antecubital vein at times -30, 0, 3, 5, 10, 20, 30, 45, 60, and 90 min. The results showed that urinary zinc excretion, and renal zinc clearance were significantly higher during the zinc and glucose tolerance tests than in the control condition. on the other hand, renal zinc clearance was more elevated during the glucose tolerance test than during the zinc tolerance test. Variations in zinc tubular reabsorption and glomerular filtration rate were not detected. The results suggest that urinary excretion and renal clearance of zinc in healthy subjects increase during acute zinc ingestion and glucose infusion. Although zinc ingestion raised urinary zinc excretion...

Renal excretion of zinc in normal individuals during zinc tolerance test and glucose tolerance test

Brandao-Neto, J.; Shuhama, T.; Pimenta, W. P.; Piesco, R. V.; Castro, A. V B; Mazeto, G. M G S; Chung, J. S.; Franco, R. J S; Curi, P. R.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 62-67
ENG
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The urinary excretion, renal clearance, and tubular reabsorption of zinc were investigated in 30 adult healthy subjects under basal conditions and during the zinc and glucose tolerance tests. After a 12h overnight fast, each subject was submitted to renal clearance of zinc. The procedures were performed between 8.00 and 12.00 a.m., after emptying the bladder and ingestion of 4 ml deionized water/kg body weight at 8.00 a.m. The first urine sample was collected at 10.00 a.m., and the second at 12.00 a.m. A dose of 110 mg ZnSO47H2O was administered orally to each subject, diluted in 20 ml deionized water, at time 0 min. Blood samples were collected from an antecubital vein at times -30, 0, and 30 min and at 30 min intervals up to 240 min. Glucose was administered intravenously (0.5 ml 50%/kg body weight) during the first 3 min of the test, and blood samples were collected from an unconstricted, contralateral, antecubital vein at times -30, 0, 3, 5, 10, 20, 30, 45, 60, and 90 min. The results showed that urinary zinc excretion, and renal zinc clearance were significantly higher during the zinc and glucose tolerance tests than in the control condition. On the other hand, renal zinc clearance was more elevated during tile glucose tolerance test than during the zinc tolerance test. Variations in zinc tubular reabsorption and glomerular filtration rate were not detected. The results suggest that urinary excretion and renal clearance of zinc in healthy subjects increase during acute zinc ingestion and glucose infusion...

Relative bioavailability of zinc in supplemental inorganic and organic sources for Nile tilapia Oreochromis niloticus fingerlings

Do Carmo E Sá, M. V.; Pezzato, L. E.; Barros, M. M.; De Magalhães Padilha, P.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 273-281
ENG
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A 90-day feeding experiment was conducted with sex reversed Nile tilapia (Oreochromis niloticus) fingerlings fed purified or practical diets supplemented with different zinc sources to evaluate fish growth performance and zinc and iron retention in fish bones, fillets, liver, skin and eyes. The relative bioavailability value (RBV) of zinc in the supplemental sources tested was also calculated. Fish were fed with isonitrogenous and isoenergetic purified or practical diets supplemented with 150 mg Zn kg -1, as zinc sulphate monohydrate (ZnSO 4), zinc oxide (ZnO) or zinc amino acid complex (Zn-AA). The feeding trial was conducted in 30, 50 L aquaria where four 0.66 ± 0.01 g (mean ± SD) fingerlings were initially stocked. No significant differences were observed for any growth performance variables (P > 0.05). In practical diets, only ZnSO 4 and ZnO presented bone zinc retention similar to that for the standard zinc source. Zinc concentration in the bone of fish fed practical diet supplemented with Zn-AA (171 ± 3.62 μg g -1) was significantly lower than that verified for the practical diets supplemented with the standard zinc source (200 ± 17.7 μg g -1) or with ZnSO 4 (204 ± 19.9 μg g -1). Assuming the concentration of zinc in bones as the response criterion...

Apparent absorption of zinc from supplemental inorganic and organic sources to Nile tilapia Oreochromis niloticus juveniles

Do Carmo e Sá, Marcelo Vinícius; Pezzato, Luiz Edivaldo; Barros, Margarida Maria; De Magalhães Padilha, Pedro
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 375-383
ENG
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Nile tilapia Oreochromis niloticus fingerlings were fed with purified or practical diets, supplemented with 150 Ing Zn/kg, from different sources. Dry matter (DM), crude protein (CP), ether extract (EE), and gross energy (GE) apparent digestibility coefficients (ADC), as well as zinc, copper, calcium, and phosphorus apparent absorption coefficients (AAC) were determined by the addition of 0.1% chromic oxide to the diets. The supplemental zinc sources utilized were commercial grade zinc sulfate monohydrate (ZnSO 4), zinc oxide (ZnO) and a zinc amino acid complex (Zn-AA). Analytical grade zinc sulfate heptahydrate was also utilized as a standard reference zinc source. There was a significant difference between purified (74.9%) and practical (41.3%) zinc AAC for the ZnO supplemented diets (P < 0.05). The supplemental zinc sources presented similar AAC when purified diets were utilized. However, ZnSO 4 was the best supplemental zinc source when practical type diets were used. There were no significant differences between supplemental zinc AAC from ZnS0 4 (68.9%), and supplemental zinc AAC from Zn-AA (61.3%) in practical diets, but Zn-AA diet showed a statistically lower zinc AAC when compared with the standard zinc source diet (75.6%). The practical diet supplemented with ZnO had the worst supplemental zinc AAC (41.3%). Dietary copper (74.21%)...

Plasma zinc and hair zinc levels, anthropometric status and food intake of children in a rural area of Brazil

Beinner,Mark Anthony; Menezes,Maria Ângela de Barros Correia; Silva,Jose Bento Borba da; Amorim,Flavia Regina de; Jansen,Ann Kristine; Lamounier,Joel Alves
Fonte: Pontifícia Universidade Católica de Campinas Publicador: Pontifícia Universidade Católica de Campinas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2010 EN
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OBJECTIVE: The objective of this study was to investigate the levels of plasma zinc, hair zinc, growth and food consumption in children aged 6 to 24 months in a rural area of Diamantina (MG), Brazil. METHODS: Plasma and hair zinc concentrations were analyzed using flame atomic absorption spectrometry and neutron activation analysis, respectively. Weight-for-age, weight-for-height and height-for-age, expressed as Z-scores, were measured according to the World Health Organization reference curves. Dietary zinc intake was determined by a 3-day dietary recall filled out by the mother or guardian. RESULTS: Zinc deficiency was found in 11.2% and 16.8% of the children according to plasma zinc e hair zinc levels, respectively. Mean plasma zinc and hair zinc for children <11 (49) and >11 (127) months of age were 15.4 (SD=4.2) µmol L-1 and 139.5 (SD=72.1) µg g-1 and 16.0 (SD=4.5) µmol L-1 and 134.3 (SD=110.3) µg g-1, respectively. Anthropometric measurements showed that 8.0%, 6.8% and 3.4% of the children were underweight, stunted and wasted, respectively. The mean dietary intake of zinc was 3.2 (SD=2.3) mg/day. One-third of the children did not eat enough foods that contain zinc. There were no correlations among plasma zinc level, hair zinc level...

Improving reproductive efficiency of chickpea by foliar application of zinc

Pathak,Girish Chandra; Gupta,Bhavana; Pandey,Nalini
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
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Zinc deficiency is not only the cause of low productivity of crops, but it also results in low zinc content in seeds, which leads to poor dietary zinc intake. To study the effect of zinc foliar application on improving plant yield and seed zinc content for human consumption, chickpea plants were raised in refined sand culture with deficient (0.2 µM) and sufficient (1µM) supply of zinc under glass-house conditions. Prior to initiation of the reproductive phase, zinc was applied as 0.1% ZnSO4 foliar spray to both zinc sufficient and deficient plants. The plants exposed to different zinc treatments were studied for pollen and stigma structure and their involvement in fertilization and seed yield. Zinc deficiency induces flower abortion, pollen, and ovule infertility leading to low seed set and ultimately its yield. Foliar application of ZnSO4 to zinc deficient plants at the time of initiation of flowering partially reverses the adverse effect of zinc deficiency on pollen-stigma morphology, pollen fertility, and greatly enhanced seed yield of plants. Zinc foliar application improved not only the boldness and vigor of seeds in zinc-deficient plants, but also the seed zinc content in zinc-deficient seeds as well as the sufficient ones.

Over-expression of an Arabidopsis zinc transporter in Hordeum vulgare increases short-term zinc uptake after zinc deprivation and seed zinc content

Ramesh, S.; Choimes, S.; Schachtman, D.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
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Increasing the zinc content of cereal grains will be important for improving human nutrition. Improved plant zinc efficiency will lead to increased yields when available zinc is limiting plant growth. The aim of our work was to test how the over-expression of zinc transporters in cereals affects plant growth, seed mineral content, and zinc transport rates. Known zinc transporters from Arabidopsis were over-expressed in Hordeum vulgare cv. Golden Promise by means of a ubiquitin promoter. Multiple transgenic lines were obtained, and the locus number and expression levels were verified. Transgenic lines were tested in longterm growth and short-term uptake experiments. Seeds from transgenic lines grown in soil had higher zinc and iron contents than controls. Short-term uptake rates were higher in the transgenic lines after zinc deprivation. Resupply of zinc after a period of deprivation resulted in the rapid decrease in zinc uptake even in transgenic lines in which a zinc transporter gene was constitutively expressed. Similar to processes in yeast and Arabidopsis, we hypothesize that this rapid decrease in zinc transport activity may be caused by the degradation of transporters in response to zinc-sufficient conditions. In the long-term growth experiments...

The role of zinc in preventing fetal dysmorphology and brain injury mediated by maternal exposure to infection in pregnancy.

Chua, Joanne Sing Cheng
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2009
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Maternal exposure to viral and bacterial infection during pregnancy is associated with fetal dysmorphology and neurodevelopmental disorders including schizophrenia, cerebral palsy, autism and mental retardation. Previous studies in our laboratory using an established mouse model of endotoxin-induced fetal dysmorphology have led to the hypothesis that birth defects caused by infections during pregnancy are the result of fetal zinc deficiency resulting from the induction of a zinc-binding protein, metallothionein (MT) in the maternal liver as part of the maternal inflammatory response. Thus, we predicted that zinc deficiency would exacerbate the negative fetal outcomes caused by bacterial endotoxin lipopolysaccharide (LPS) and that zinc supplementation would protect against LPS-mediated teratogenicity. This premise was investigated herein and was extended to investigate underlying molecular mechanism, including the identification of markers of neurodevelopmental damage following LPS administration in early and late pregnancy, and to determine the influence of zinc treatment on any changes in expression of these markers. In Chapter 2 it was demonstrated that prenatal exposure to LPS on gestational day (GD) 8 resulted in the development of physical birth defects including exencephaly...

Zinc biofortification of rice in China: a simulation of zinc intake with different dietary patterns

Qin, Y.; Melse-Boonstra, A.; Yuan, B.; Pan, X.; Dai, Y.; Zhou, M.; Wegmueller, R.; Zhao, J.; Kok, F.; Shi, Z.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
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A cross-sectional survey of 2819 adults aged 20 years and above was undertaken in 2002 in Jiangsu Province. Zinc intake was assessed using a consecutive 3-day 24-h dietary recall method. Insufficient and excess intake was determined according to the Chinese Dietary Recommended Intakes. Four distinct dietary patterns were identified namely “traditional”, “macho”, “sweet tooth”, and “healthy”. Intake of zinc from biofortified rice was simulated at an intermediate zinc concentration (2.7 mg/100 g) and a high zinc concentration (3.8 mg/100 g) in rice. Average total zinc intake was 12.0 ± 3.7 mg/day, and insufficiency of zinc intake was present in 15.4%. Simulated zinc intake from biofortified rice with intermediate and high zinc concentration decreased the prevalence of low zinc intake to 6.5% and 4.4%, respectively. The effect was most pronounced in the “traditional” pattern, with only 0.7% of insufficiency of zinc intake remaining in the highest quartile of the pattern. Zinc intake was inversely associated with the “sweet tooth” pattern. Zinc biofortifed rice improves dietary zinc intake and lowers risk for insufficient zinc intake, especially for subjects with a more “traditional” food pattern, but less for subjects with a “sweet tooth” food pattern.; http://arxiv.org/abs/arXiv:1205.0019; Yu Qin...

AdcA and AdcAII employ distinct zinc acquisition mechanisms and contribute additively to zinc homeostasis in Streptococcus pneumoniae

Plumptre, C.D.; Eijkelkamp, B.A.; Morey, J.R.; Behr, F.; Couñago, R.M.; Ogunniyi, A.D.; Kobe, B.; O'Mara, M.L.; Paton, J.C.; McDevitt, C.A.
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
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Streptococcus pneumoniae is a globally significant human pathogen responsible for nearly 1 million deaths annually. Central to the ability of S. pneumoniae to colonize and mediate disease in humans is the acquisition of zinc from the host environment. Zinc uptake in S. pneumoniae occurs via the ATP-binding cassette transporter AdcCB, and, unusually, two zinc-binding proteins, AdcA and AdcAII. Studies have suggested that these two proteins are functionally redundant, although AdcA has remained uncharacterized by biochemical methods. Here we show that AdcA is a zinc-specific substrate-binding protein (SBP). By contrast with other zinc-binding SBPs, AdcA has two zinc-binding domains: a canonical amino-terminal cluster A-I zinc-binding domain and a carboxy-terminal zinc-binding domain, which has homology to the zinc-chaperone ZinT from Gram-negative organisms. Intriguingly, this latter feature is absent from AdcAII and suggests that the two zinc-binding SBPs of S. pneumoniae employ different modalities in zinc recruitment. We further show that AdcAII is reliant upon the polyhistidine triad proteins for zinc in vitro and in vivo. Collectively, our studies suggest that, despite the overlapping roles of the two SBPs in zinc acquisition, they may have unique mechanisms in zinc homeostasis and act in a complementary manner during host colonization.; Charles D. Plumptre...

Factores asociados a deficiencia de zinc en niños colombianos entre 1 y 4 años de edad

Mesa Acosta, Andrea Carolina
Fonte: Facultad de medicina Publicador: Facultad de medicina
Tipo: info:eu-repo/semantics/bachelorThesis; info:eu-repo/semantics/acceptedVersion Formato: application/pdf
Publicado em 17/10/2014 SPA
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Introducción: Las deficiencias de micronutrientes continúan siendo un problema de salud pública en la población infantil, dentro de las ellas se ha encontrado a la deficiencia de zinc causa importante de morbi-mortalidad en los países en desarrollo, la nutrición adecuada de zinc es esencial para un crecimiento adecuado, inmunocompetencia y desarrollo neuroconductual; se dispone de información insuficiente sobre el estado de zinc en la población preescolar lo cual dificulta la expansión de las intervenciones para el control de su deficiencia. Colombia presenta una deficiencia de este micronutriente, considerándose a nivel mundial como un problema de salud pública moderado a severo. Una evaluación sobre la prevalencia y factores determinantes asociados puede proporcionar datos sobre el riesgo de deficiencia de zinc en una población, considerando factores demográficos, sociales y nutricionales que podrían predisponer a la población preescolar colombiana a sufrir este déficit. Metodología: Estudio observacional de corte transversal que incluyó 4275 niños entre 1 y 4 años, utilizando datos de la Encuesta Nacional de Situación Nutricional (ENSIN-2010). Se realizaron análisis bivariados y multivariados para determinar factores asociados positiva y negativamente con deficiencia de zinc. Resultados: El 49...

Zinc supplementation in infants with asymmetric intra uterine growth retardation; effect on growth, nutritional status and leptin secretion

Bueno,O.; Bueno,G.; Moreno,L. A.; Nuviala,R. J.; Pérez-González,J. M.; Bueno,M.
Fonte: Nutrición Hospitalaria Publicador: Nutrición Hospitalaria
Tipo: info:eu-repo/semantics/article; journal article; info:eu-repo/semantics/publishedVersion Formato: text/html; application/pdf
Publicado em 01/06/2008 ENG
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Objectives: To analyse the effect of zinc supplementation in growth and nutritional status of a homogeneous group of newborns with intra uterine growth retardation and asymmetric growth. The effect of changes of zinc status on growth and leptin serum concentrations was also analysed. Population and methods: A double blind, randomised clinical trial was designed in order to detect differences in growth between zinc and placebo groups during the first 6 months of life. 31 infants were included either to the zinc group (n = 14) (38.8 ± 1.4 weeks GA, 2,171 ± 253 g body weight) or the placebo group (n = 17) (38.9 ± 1.1 weeks GA, 2,249 ± 220 g body weight). The zinc group received a supplement of 3 mg elemental zinc per day (as zinc sulphate). Results: There were not significant differences between groups for anthropometric measurements through the study period. We found a significant effect of the study group, in hair zinc concentrations, but not in serum zinc concentrations; post-hoc comparisons for hair zinc revealed that there were significant differences between groups at 1, 2, and 6 months of age. Changes in serum and hair zinc concentrations from baseline to 6 months, showed significant correlations with changes in weight/age and length/age z-scores...

Relación entre las cantidades de cobre y zinc administradas a pacientes graves con nutrición parenteral total y los niveles de cobre y zinc en plasma y eritrocitos

Menéndez,A. M.; Weisstaub,A.; Montemerlo,H.; Alloatti,S.; Guidoni,M. E.; Rusi,F.; Portela,M. L. de
Fonte: Nutrición Hospitalaria Publicador: Nutrición Hospitalaria
Tipo: info:eu-repo/semantics/article; journal article; info:eu-repo/semantics/publishedVersion Formato: text/html; application/pdf
Publicado em 01/08/2008 SPA
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Objetivos: Evitar tanto las complicaciones por deficiencia de zinc y de cobre como los efectos adversos del exceso en pacientes graves que requirieron nutrición parenteral, estudiando la relación entre las cantidades de zinc y de cobre administradas en las mezclas de nutrición parenteral y los cambios en algunos indicadores bioquímicos de los pacientes, con respecto a zinc y cobre. Pacientes y metodología: 29 pacientes graves, adultos, con pancreatitis o sometidos a cirugía mayor abdominal. Se determinó, al inicio y al final del tratamiento (5-21 días): cobre y zinc en las mezclas de nutrición parenteral administradas y en eritrocitos (GR), zinc en plasma y cobre en suero (Espectrometría de Absorción Atómica). Resultados (promedio ± DE, rangos: entre paréntesis): los valores de zinc y cobre en las mezclas de nutrición parenteral fueron (μg/mL): zinc: 4,2 ± 1,7 (1,8 a 9,3); cobre: 0,94 ± 0,66 (0,1 a 3,1); zinc plasmático (μg/dl): inicio 80 ± 45 (29-205); final: 122 ± 56 (37-229); zinc eritrocitario (μg/dl): inicio: 2.300 ± 1.070 (790-5280); final: 2.160± 920 (790-4.440); cobre sérico (μg/dl): inicio: 124 ± 35 (62-211); final: 128 ± 41 (60-238); cobre eritrocitario (μg/dl): inicio: 72 ± 39 (4-183); final: 70 ± 41 (9-156). Los cambios porcentuales de los niveles de zinc eritrocitario correlacionaron con el zinc (mg/d) en las mezclas de nutrición parenteral (r = 0...

Evaluation of processing options for the treatment of zinc sulphide concentrates at Skorpion Zinc

Fuls,H.F; Petersen,J
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2013 EN
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Skorpion Zinc, an integrated zinc mine and refinery located in the south of Namibia, has a production capacity of 150 000 t/a of special high grade (SHG) zinc. The Skorpion zinc oxide resource will be depleted by 2017. Extensive exploration drilling for additional zinc oxides was conducted without success. With the abundant availability of zinc sulphide concentrates regionally (Black Mountain and Gamsberg in the Northern Cape or Rosh Pinah Zinc and new deposits in the Rosh Pinah region) the life of the operation can be extended by processing of zinc sulphide concentrates. The leach kinetics of zinc sulphides is vastly slower than for oxides, preventing the processing of zinc sulphides in the existing process under current conditions, and Skorpion Zinc faces the challenge to identify a suitable zinc sulphide treatment process that can be integrated with the existing plant. Various zinc sulphide processing options were identified through an extensive literature search and non-viable options were eliminated. Mass and energy balances were established for potential options and an economic evaluation (including capital and operating cost estimation) was conducted to identify a suitable process. It is concluded that ferric leaching of sphalerite in a sulphate medium under atmospheric or pressure leach conditions are suitable processes for Skorpion Zinc. These processes present advantages over all other zinc processing options when elemental sulphur is preferred as the final deportment for sulphide sulphur. Both these processes can be integrated into the existing refinery and will be able to process concentrates with a wide composition range.