Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Validation of ISO 17586 soil quality : extraction of trace elements using dilute nitric acid
Vark, W. van; Harmsen, J. - \ 2016
Alterra, Wageningen-UR (Alterra-rapport 2693) - 55 p.
soil - soil quality - trace elements - standards - bioavailability - iso - extraction - bodem - bodemkwaliteit - sporenelementen - normen - biologische beschikbaarheid - extractie
Aparte toediening geeft betere resultaten : alternatief voor ijzerchelaat in praktijk getoetst met positief resultaat
Hoogstraten, K. van; Voogt, W. - \ 2015
Onder Glas 12 (2015)5. - p. 23 - 25.
glastuinbouw - plantenvoeding - sporenelementen - polyfosfaten - bemesting - toepassing - opname (uptake) - effecten - ijzerhoudende meststoffen - chelaten - meststofdragers - greenhouse horticulture - plant nutrition - trace elements - polyphosphates - fertilizer application - application - uptake - effects - iron fertilizers - chelates - fertilizer carriers
IJzer is een onmisbaar voedingselement, dat nodig is voor de vorming van bladgroen en zo chlorose voorkomt. Omdat het element normaal niet opgelost blijft – en dan niet beschikbaar is voor de plant – zijn al jaren ijzerchelaten voorhanden. Bij een nieuwe meststof is het ijzer op een andere manier gebonden, namelijk met een combinatie van polyfosfaten. Bij toediening via een aparte bak blijkt het in de praktijk goed te werken. De meststof heeft daarnaast andere effecten, zoals minder bladrand en makkelijker UV-ontsmetting. Recent onderzoek en praktijkervaringen geven vergelijkbare resultaten.
Evaluation of dietary diversity scores to assess nutrient adequacy among rural Kenyan women
Ngala, S.A. - \ 2015
Wageningen University. Promotor(en): Frans Kok, co-promotor(en): Inge Brouwer; A.M. Mwangi. - Wageningen : Wageningen University - ISBN 9789462574236 - 149
kenya - gezondheid van vrouwen - voedingsstoffen - sporenelementen - voedingsgeschiktheid - diversiteit - plattelandsbevolking - kwantitatieve methoden - kwalitatieve methoden - women's health - nutrients - trace elements - nutritional adequacy - diversity - rural population - quantitative methods - qualitative methods

Evaluation of dietary diversity scores to assess nutrient adequacy among rural Kenya women

S. A. Ngala

Abstract

Background:The major cause of micronutrient deficiencies are low intake due to monotonous diets, especially among women of child bearing age. Dietary diversity score has been found to be a good proxy indicator for micronutrient adequacy. However, there are still outstanding methodological questions related to seasonal effects, food intake methods, selection of foods and the cut-off for estimating the prevalence of acceptable nutrient adequacy. This thesis evaluated the performance of a simple dietary diversity score for assessing nutrient adequacy in the diets of rural women in Kenya.

Methods: The study was conducted in Mbooni Division, Makueni District, Kenya among non-pregnant, non-lactating women of reproductive age having a child between 2-5 years. Food consumption data was collected by 3 non-consecutive 24hour-recalls and a qualitative 24hour-recall in pre-harvest (period 1, October 2007, n=73) and post-harvest (period 2, April 2008, n=203) seasons. Dietary diversity scores (DDS) were derived based on 10 and 13 food groups with minimum intake threshold per food group of 0 and 15 g respectively. Mean probability of adequacy (MPA) was calculated based on intake of 11 micronutrients.

Results: The dietary diversity score (DDS) and mean probability of adequacy (MPA) were significantly but moderately associated in both seasons (r=0.40 and r=0.38 period 1 and 2) and the association was independent of season (p=0.45). The DDS from a qualitative 24 hour recall (DDSql) showed little agreement with quantitative 24 hour recall (DDSqn) with a mean difference (DDSqn-DDSql) of -0.51±1.46 (Period 1) and -0.58±1.43 (period 2), with lower correlation between MPA and DDS for DDSql (r=0.14 and 0.19 in period 1 and 2, p>0.05) compared to DDSqn (r=0.40 and 0.54 in period 1 and 2, p<0.01). The Informative food-based scores and the food group-based scores were moderately associated with mean probability of adequacy (r=0.54-0.59 in period 1; r=0.37- 0.45 in period 2) with higher values for informative food based scores. The Minimum Dietary Diversity of Women (MDD-W) and mean probability of adequacy were significantly but moderately associated in both seasons (r=0.43-0.58 in period 1; r=0.24-0.50 in period 2) with but the use of a cutoff of consuming 5 or more food groups as indication of nutrient adequacy resulted in high total misclassification in both periods.

Conclusion: A dietary diversity score can be used as a simple proxy for micronutrient adequacy, independent of season. The dietary diversity score derived from qualitative free-listing 24-hour recall formed a poor indicator, needing further refinement to improve its performance. The informative food-based score performs moderately better in predicting nutrient adequacy, but its advantages do not outway those of the food group-based scores, and the latter is therefore preferred. The Minimum Dietary Diversity score for Women, formed a good indicator to predict nutrient adequacy, but using the cutoff of 5 or more food groups resulted in an overestimation of prevalence of adequate intake in our resource poor population.

Speciation of trace metals and their uptake by rice in paddy soils
Pan, Y. - \ 2015
Wageningen University. Promotor(en): Rob Comans, co-promotor(en): Gerwin Koopmans; J. Song. - Wageningen : Wageningen University - ISBN 9789462572744
oryza sativa - rijst - padigronden - sporenelementen - voedingsstoffenopname (planten) - bodemchemie - natte rijst - oplosbaarheid - rice - paddy soils - trace elements - nutrient uptake - soil chemistry - flooded rice - solubility

Rice (Oryza sativa L.) is the most important staple food in South and Southeast Asia and plays a crucial role in food security. However, with fast urbanization and industrialization and economic growth in these parts of the world, the production and quality of rice has become an increasing concern, because contamination of paddy soils with trace metals in industrialized areas can lead to yield reduction of rice, a decline in the nutritional quality of the rice, and an accumulation of trace metals in rice grains. In this PhD thesis, I used a combination of experimental research and mechanistic modeling to investigate the solubility of trace metals in paddy soils exposed to alternating flooding and drainage conditions and to link trace metal solubility to the uptake by rice plants over time. This work contributes to the understanding of how redox chemistry affects the solubility of trace metals in flooded soil and sediment systems and provides a tool for the measurement of the free trace metal concentrations in flooded soil and sediment systems in situ in the form of the field DMT.

Voederbomen in trek
Eekeren, N.J.M. van; Luske, B.L. ; Vonk, M. ; Anssems, E. - \ 2015
V-focus 12 (2015)1. - ISSN 1574-1575 - p. 38 - 39.
melkveehouderij - geitenhouderij - schapenhouderij - melkveevoeding - geitenvoeding - schapenvoeding - bomen als veevoer - herkauwersvoeding - mineralenopname - sporenelementen - dairy farming - goat keeping - sheep farming - dairy cattle nutrition - goat feeding - sheep feeding - fodder trees - ruminant feeding - mineral uptake - trace elements
Bladeren en twijgen van bomen en struiken hebben potentie in het rantsoen van koeien, geiten en schapen, omdat ze een aanvullende bron zijn van eiwit, mineralen en sporenelementen. Daarnaast bevatten veel bomen secundaire plantenstoffen die een positief effect kunnen hebben op de vertering en de gezondheid van herkauwers. In het Praktijknetwerk Voederbomen en Functioneel Landgebruik (www.voederbomen.nl) is de inpasbaarheid van voederbomen op melkveebedrijven getest.
Elementen chloor en nikkel ook essentieel voor groei en ontwikkeling : er is meer dan hoofd- en sporenelementen
Kierkels, T. ; Heuvelink, E. - \ 2014
Onder Glas 11 (2014)5. - p. 26 - 27.
glastuinbouw - plantenvoeding - sporenelementen - metaalelementen - plantgezondheid - sporenelementtekorten - mestbehoeftebepaling - toepassing - greenhouse horticulture - plant nutrition - trace elements - metallic elements - plant health - trace element deficiencies - fertilizer requirement determination - application
Het was zo simpel: planten hebben twaalf elementen echt nodig, verdeeld in zes hoofdelementen en zes sporenelementen. Maar dat beeld kan beter op de schop. Van minstens twee elementen is aangetoond dat ook zij noodzakelijk zijn, sommige andere zijn essentieel voor bepaalde planten en nog een hele groep kan soms de groei en kwaliteit bevorderen. En zoals zo vaak: veel is nog onbekend.
Paling analyses Ecofide
Hoek-van Nieuwenhuizen, M. van - \ 2013
IJmuiden : IMARES (Rapport / IMARES Wageningen UR C196/13) - 13
palingen - european eels - representatieve monstername - monsters - chemische analyse - polychloorbifenylen - organo-tinverbindingen - vet - droge stof - sporenelementen - eels - representative sampling - samples - chemical analysis - polychlorinated biphenyls - organotin compounds - fat - dry matter - trace elements
De opdracht bestond uit het karakteriseren, fileren en homogeniseren tot een mengmonster van de door Ecofide aangeleverde set palingen; het uitvoeren van chemische analyses in het mengmonster en het rapporteren van de resultaten. Dit rapport omvat een korte omschrijving van de toegepaste methoden, een kwaliteitsparagraaf en een presentatie van de resultaten in Exceltabellen.
Development of iron and zinc enriched mungbean (Vigna radiata L.) cultivars with agronomic traits in consideration
Singh, R. - \ 2013
Wageningen University. Promotor(en): Richard Visser, co-promotor(en): Sjaak van Heusden. - S.l. : s.n. - ISBN 9789461736840 - 175
vigna radiata - mungbonen (green gram) - mungbonen - sporenelementen - ijzer - zink - plantenveredeling - genetische diversiteit - voeding - india - voedselsoevereiniteit - green gram - mung beans - trace elements - iron - zinc - plant breeding - genetic diversity - nutrition - food sovereignty

Malnutrition in India, particularly among women, children and adolescents is an emergency that needs immediate attention in this fast growing and developing country. Micronutrient deficiencies are threatening public health in India more and more. Deficiencies of micronutrients drastically affect growth, metabolism and reproductive phase in humans as it does in plants and animals. Cereal and pulse based Indian diets are qualitatively deficient in micronutrients such as iron, calcium, vitamin A and zinc. This is due to a low intake of income-elastic protective foods such as pulses, vegetables, fruits, and foods of animal origin. It is presumed that if we restore the geographical connection between food production and consumption in local food networks it will help in solving this nutritional problem in India. This offers new opportunities to tailor science & technology to location specific patterns of food production and consumption, which may lead to environmentally and socially sustainable agriculture. Despite global pressure (including from science and technology) to focus agricultural cultivation on a limited number of food crops, still many so-called orphan crops like mungbean do exist and are cultivated in location-specific crop rotation systems. Particularly, the seed legumes are of major nutritional importance, especially in developing countries, because they have high protein contents of good biological value. Out of the total sales of mungbean, about half of the sales are within the village which clearly establishes the need for development of infrastructure and facilities at the village level to serve the interests of the farm households. Moreover, it is also necessary to shift the focus of development from the urban market centres (largely developed) to the rural market centres. Linking breeding, nutrition, processing and standardisation of food products, may be designed within the experimental framework of empowering poor farmers. Hence, tailoring plant, food and social sciences to empower local mungbean production and consumption patterns has been designed as an interdisciplinary program of plant breeding, food technology, human nutrition and sociology of science and technology. Thus the ‘Tailoring Food Sciences to Endogenous Patterns of Local Food Supply for Future Nutrition’ (TELFUN) project aimed to help people in selecting their own way of local food production, processing and consumption of the best suited local food. The main objective is to strengthen “The Science in Society” approach by remodeling participatory research and development and the general aim of TELFUN was to attune disciplinary research objectives within an interdisciplinary framework to enhance food sovereignty and to improve mungbean based production and consumption pattern in selected research area (Haryana, India). As an example our research focused on further improving one of the potential nutritional crops, namely mungbean. The present work emphasizes on mungbean in general and especially on the available micronutrient variation in the mungbean germplasm. The mungbean (green gram), Vigna radiata (L.) Wilczek is native to the Indian subcontinent. They are warm season annuals, highly branched and having trifoliate leaves like the other legumes. Seeds of mungbean are small, ovoid in shape, and green in color. Mungbean seeds are high in protein (21%–28%), calcium, phosphorus and certain vitamins. Moreover they are easily digested and they replace scarce animal protein in human diets in vegetarian populations of the world. The selected area of research centres contain a high level of local biodiversity and are the locations for domestication of mungbean. This legume has co-evolved with their natural ecosystems and is well-adapted to withstand the local biotic and abiotic stresses. This will help in enabling the reconnection of the cultivation of the mungbean with their natural environments. Moreover, as domestication has taken place by local farmers during many centuries, they have accumulated local endogenous knowledge, which is very relevant for local food networks (www.telfun.info). Thus to explore the potential mungbean network, the present thesis set its objectives. They were: i) identification of the major constraints, limitations and preferences of producer’s with regard to mungbean, ii) assessing the diversity in the available germplasm and assessing the effects of different environments on selected cultivars for their mineral micronutrients and iii) to make a start to develop tools for marker assisted breeding with regard to iron and zinc.

Socioeconomic differences in micronutrient intake and status in Europe
Novakovic, R.N. - \ 2013
Wageningen University. Promotor(en): Pieter van 't Veer; Lisette de Groot, co-promotor(en): Anouk Geelen; M. Gurinovic. - [S.l. : S.n. - ISBN 9789461735775 - 154
sporenelementen - voedingsstoffenopname (mens en dier) - voedingstoestand - sociale economie - sociaal-economische positie - europa - vitaminen - trace elements - nutrient intake - nutritional state - socioeconomics - socioeconomic status - europe - vitamins

The aim of this thesis was to evaluate micronutrient intake and status of socioeconomic disadvantaged populations, such as from Central and Eastern European (CEE) as compared to other European populations, and low socioeconomic status (SES) groups as compared to high SES groups within European countries. We addressed the micronutrients that have been prioritized because of their relevance for nutritional health by the EC-funded EURRECA Network of Excellence. Moreover, we assessed the association between folate intake and status which can be used in the process of setting folate DRVs.

Micronutrient intake and status of CEE countries versus other European countries

CEE countries have recently experienced rising income inequalities over a period of economic transition. There is some evidence that these reforms have been accompanied by health inequalities. Inadequacy in micronutrient intake and status may contribute to these inequalities. Because in more affluent Western European countries wide ranges in micronutrient intake and status are observed, we studied if low micronutrient intake and status levels are prevailing in CEE. The findings from this thesis signal no differences in micronutrient intake and status between CEE populations in comparison to those of other European regions with the exception of calcium intake in adults and iodine status in children that were lower in CEE than in other European regions. Since data from Western Europe indicate that inadequacies do exist among SES strata, more insight in the nutritional situation of lower SES populations in CEE and an understanding of both its determinants and consequences is needed. It is important to mention that evidence from grey literature added to that from open access sources. Fundamental to further studying of nutritional health in CEE, is suitable data. We underline the necessity for conducting nutritional surveillances on micronutrient intake and status in CEE as we have identified significant knowledge gaps for many life-stage groups.

Differences in micronutrient intake between SES groups

Considering that not enough studies have addressed the relationship between SES and micronutrient intake and status in their analyses of nutritional health, we performed a systematic review on this topic and we used data from the large European EPIC cohort to address that issue.

To be able to conclude on socioeconomic, i.e. educational, occupational and income, inequalities associated with intake and status of prioritized micronutrients for all life stages in Europe, substantial knowledge gaps should be filled. Currently, data are mostly available for the intake of calcium, vitamin C and iron as collected from adults in Western European countries. When either of the above mentioned SES indicators was applied to estimate relative differences in micronutrient intake and status between the lowest and the highest SES category within one study, the results often, but not consistently, indicated a lower intake and/or status in low versus high SES groups. For example, in eight out of ten studies a lower intake for calcium intake was found with relative differences ranging from -2 to -14%. Similar patterns were found for vitamin C and iron: in eleven out of twelve studies relative differences ranged from -5 to -48% for vitamin C, whereas in nine of ten studies on iron relative differences went up to -14%. Studies on intake and/or status of folate, vitamin B12, zinc, iodine, and intake of vitamin D, selenium and copper were limited. Still, when differences were observed, it appeared that lower intake in low than in high SES groups was found except for vitamin B12 and zinc for which the findings were inconsistent.

Furthermore, using education as a proxy for SES, we assessed differences in micronutrient intake between educational levels using the individual-participant data on European adults and elderly from the EPIC cohort. Based on data from 10 Western European countries it appeared that intake of calcium (except in France and a distinctive ‘health-conscious’ group in the UK), folate (except in Greece), and vitamin C was lower in the lowest than in the highest education groups: relative differences ranged up to 12, 13 and 23%, respectively. The intake of iron differed marginally, whereas the variation in intake of vitamins D and B12 was inconsistent. The observed association between educational level and intake of micronutrients was the same for men and women. Furthermore, differences in micronutrient intake were found to be larger between countries than between SES groups.

With respect to SES differences in micronutrient intake and status, there are significant gaps in the open source literature for many life-stage groups in Europe, but particularly in CEE countries. There is a clear need for cross-country and within country comparative research and for the monitoring of trends in dietary intake across different SES groups and European countries.

Relationship between folate intake and status to add complementary evidence for deriving folate dietary reference values (DRVs)

DRVs are under continuous review and periodic revision as the cumulative evidence base and body of knowledge evolve. Folate is considered a public health priority micronutrient for which re-evaluation of DRVs is needed. For this micronutrient, a systematic review of observational studies on the relationship between intake and status was done followed by meta-analysis. The intake of folate was significantly associated with markers of folate status. The results of our meta-analysis showed that an average person with a folate intake of 100 µg/day has a serum/plasma folate status concentration that is 26% higher and a red blood cell folate status that is 21% higher than a person who has a folate intake of 50 µg/day; plasma homocysteine was found to be 16% lower. The difference between natural food folate and that from supplements and fortified foods (folic acid) significantly influenced the estimated relationship between folate intake and serum/plasma status. Associations were stronger when assessed as folate from the diet than as folate from diet and supplements. Dietary assessment method did not significantly influence the association, although pooled estimates were somewhat higher when FFQs were used as compared to 24-hour recalls combined with food records. To focus on the impact of poor intakes on related health outcomes, data modelling can be conducted to produce estimates for Average Nutrient Requirements. For this analysis datasets and statistical models developed within the EURRECA NoE are available and can be used.

Overall, further research would benefit from methodologically comparable data on food intake in all age ranges, especially on so far understudied CEE populations. Both intakes obtained through diet and from supplements and fortified foods should be assessed. Monitoring of trends across SES strata should be done with standardized SES measurements that would also facilitate cross-country comparative research. The findings on the level and distribution of micronutrient intake and status could be used for development of food based dietary guidelines. To make them effective in meeting populations’ micronutrient needs, they should be created accounting for the country specific dietary patterns giving consideration to the socioeconomic context.

Adviesbasis voor de bemesting van akkerbouwgewassen : sporenelementen
Haan, J.J. de; Geel, W.C.A. van - \ 2013
Kennisakker.nl 2013 (2013)20 maart.
akkerbouw - gewassen - mest - sporenelementen - borium - mangaan - koper - ijzer - zink - molybdeen - toepassing - dosering - bemesting - arable farming - crops - manures - trace elements - boron - manganese - copper - iron - zinc - molybdenum - application - dosage - fertilizer application
In dit artikel worden adviezen gegeven voor de bemesting van akkerbouwgewassen met de sporenelementen; borium, mangaan, koper, ijzer, zink en molybdeen.
Verkenning mogelijke schaarste aan micronutriënten in het voedselsysteem
Chardon, W.J. ; Oenema, O. - \ 2013
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2413) - 43
bodemchemie - bemesting - mineralen - sporenelementen - kringlopen - borium - kobalt - koper - molybdeen - selenium - zink - schaarste - akkerbouw - tuinbouw - soil chemistry - fertilizer application - minerals - trace elements - cycling - boron - cobalt - copper - molybdenum - zinc - scarcity - arable farming - horticulture
Onder een micro-nutriënt wordt verstaan: een element dat essentieel is voor de groei en het functioneren van de plant, een dier of de mens, maar waarvan de benodigde hoeveelheid relatief klein is. In dit rapport zijn zes elementen geselecteerd omdat zij aantoonbaar essentieel zijn voor meerdere soorten gewassen of voor de veehouderij, en omdat de mate van vóórkomen in de aardkorst relatief gering is, waardoor (toekomstige) mondiale schaarste denkbaar is. Deze elementen zijn resp. borium, kobalt, koper, molybdeen, seleen en zink (B, Co, Cu, Mo, Se, en Zn). Alleen voor B en Se dragen de akker- en tuinbouw en de veehouderij significant bij aan het huidige mondiale gebruik: Se in de veehouderij 11% van totaal, en B in akker- en tuinbouw 12% van totaal verbruik. Prijsfluctuaties van Se en B zijn groot en wijzen op schaarste; binnen de industrie vindt recycling van deze elementen nauwelijks plaats. Binnen het voedselsysteem vindt recycling plaats van micronutriënten via hergebruik van dierlijke mest, gewasresten, compost en zuiveringsslib. Voor alle industrieel gebruikte micronutriënten zijn er alternatieven, behalve voor Co. In bodems vindt niet-duurzame ophoping plaats van Cu en Zn via mest, vooral in gebieden met een hoge veedichtheid.
Mineralen-, sporenelementen- en vitaminenbehoeften van paarden
Top, A.M. van den; Blok, M.C. ; Everts, H. - \ 2012
Lelystad : CVB, Productschap Diervoeder (CVB-documentatierapport nr. 54) - 68
paarden - diervoeding - voeding - voedering - voedingsstoffen - mineralenvoeding - sporenelementen - vitaminen - horses - animal nutrition - nutrition - feeding - nutrients - mineral nutrition - trace elements - vitamins
In deze publicatie wordt beschreven hoe de in CVB verband tot stand gekomen voedernormen voor deze voedingsstoffen tot stand zijn gekomen. De publicatie is het resultaat van een deskstudie waarbij allereerst de Duitse DLG normen en de Amerikaanse NRC normen zijn geëvalueerd. Daar waar nodig is gericht gekeken of er nieuwe studies beschikbaar zijn, of is teruggegrepen op de oorspronkelijke publicaties. Voor de macromineralen (calcium, fosfor, magnesium, natrium, kalium, chloor) zijn de voedernormen gebaseerd op de zgn. factoriële methode. Voor sporenelementen en de vitamines bleek deze benadering niet mogelijk. Het rapport bevat een groot aantal tabellen waarin de voedernormen voor de genoemde nutriënten voor alle relevante fysiologische stadia.
Trend analysis of copper and zinc in animal feed
Adamse, P. ; Egmond, H.J. van; Polanen, A. van; Bikker, P. ; Jong, J. de - \ 2011
Wageningen : Rikilt - Institute of Food Safety (Report / RIKILT 2011.012)
veevoeder - voersamenstelling - sporenelementen - koper - zink - chemische analyse - classificatie - fodder - feed formulation - trace elements - copper - zinc - chemical analysis - classification
The EC has introduced maximum inclusion levels of copper and zinc salts in animal diets from 1970 onwards and reduced these levels in recent years. In this report historical values are used to give insight into trends in levels of copper and zinc in compound feeds for animals in the Netherlands. The results of these analyses will enable the nVWA (Dutch Food and Consumer Product Safety Authority) to develop a more risk-directed sampling strategy in the National Feed Monitoring program. Over 2000 feed samples are analysed for this report. The data for this analysis are from the period between 2001 and 2009. The copper and zinc data-set contains mostly feeds for piglets, (older) pigs, sheep and to a lesser extent bovine and other species.
Zuivelproducten zijn belangrijke bronnen van micronutriënten
Groot, C.P.G.M. de - \ 2011
VoedingsMagazine 24 (2011)3. - ISSN 0922-8012 - p. 11 - 13.
melkproducten - melk - voedingsstoffen - aanbevolen dagelijkse hoeveelheden - voeding en gezondheid - voedingsstoffentekorten - voedingsstoffenbehoeften - sporenelementen - milk products - milk - nutrients - recommended dietary allowances - nutrition and health - nutrient deficiencies - nutrient requirements - trace elements
Het network of excellence EURRECA heeft tien micronutriënten geselecteerd die prioriteit verdienen bij de Europese harmonisatie van de voedingsaanbevelingen. Voor veel van de micronutrienënten zijn melk en zuivelproducten belangrijke bronnen. Zo bleek tijdens een symposium in Parijs.
Estimation of micronutrient intake distributions: development of methods to support food and nutrition policy making
Verkaik-Kloosterman, J. - \ 2011
Wageningen University. Promotor(en): Pieter van 't Veer, co-promotor(en): M.C. Ocké. - [S.l.] : S.n. - ISBN 9789085859451 - 192
sporenelementen - vitaminen - voedingsstoffenopname (mens en dier) - dieet - beleid inzake voedsel - volksgezondheid - fortificatie - voedselsupplementen - trace elements - vitamins - nutrient intake - diet - food policy - public health - fortification - food supplements


Introduction
Adequate and safe micronutrient intake is important. Both insufficient and excessive intakes should be prevented as these can be associated with negative health effects. Therefore, the population intake distribution will ideally lay between insufficient and excessive intakes. For the development and evaluation of nutrition and food policy a good estimation of dietary micronutrient intake is of great importance.

Aim
Three challenges were addressed to improve the estimation of population micronutrient intake distributions: 1) how to estimate current habitual micronutrient intake when (detailed) data are lacking or data from different sources should be combined, 2) how to predict future intakes in order to support policy making, and 3) how to estimate a maximum safe fortification level per food item. The aim of this PhD-thesis is to further develop and apply statistical models which can cope with these challenges.

Methods & Results
Data from the Dutch National Food Consumption Surveys (DNFCSs) were used to develop and apply statistical models which can cope with the defined challenges. In addition, data from the Dutch food composition database (NEVO) and the Dutch dietary supplement database (NES) were used.

Three main methodological improvements have been made. First, the combination of a deterministic approach with probabilistic approaches to be able to take into account uncertainty and variability were needed. This method was applied to estimate habitual iodine and salt intake distributions. From DNFCSs no detailed information was available on the discretionary use of (iodized) salt and no up to date information was available on the use of iodized salt in industrially processed foods. Estimates of the proportion of the population discretionarily using (iodized) salt and the proportion of industrially processed foods applying iodized salt were obtained from other data sources. The model accurately estimates habitual iodine and salt intake distributions when compared with studies measuring urinary iodine and sodium excretion. Additionally a framework was developed to simulate the habitual intake distribution for potential scenarios of future fortification strategies. Within this framework, deterministic and probabilistic approaches were combined when uncertainty or variability had to be taken into account. This framework was illustrated by the estimation of habitual folate-equivalent intake for different scenarios of mandatory or voluntary fortification with folic acid. Further this framework was applied to estimate the habitual iodine intake for several potential changes in the Dutch iodine policy and also for several scenarios of salt reduction strategies.

A second methodological improvement was the development of a new statistical model to estimate habitual total micronutrient intake aggregated from food and dietary supplements. Within this 3-part model, habitual intake is estimated separately for a) intake from food for non-users of dietary supplements, b) intake from food for users of dietary supplements, and c) intake from dietary supplements for users only. Habitual total intake for the whole population was obtained by combination of the three separate habitual intake distributions (‘first shrink then add’). This 3-part model was illustrated by vitamin D intake for young children. With a more simple ‘first add then shrink’ approach the estimation of habitual total vitamin D intake distribution may give inconsistent results for the distribution of intake from foods and dietary supplements combined as compared to the intake from food only. In addition, this more simple approach may not be able to cope with multi modal distributions. With the newly developed model this inconsistency problem was solved and the multi-modal shape of the distribution as observed in the ‘raw’ data was preserved.

Third, a model calculating the maximum safe fortification level per 100 kcal of a food was developed for the Dutch situation. By considering the tolerable upper intake level and reasonable high micronutrient intakes from food and dietary supplements, the ‘free space’ for voluntary fortification was calculated. This amount was divided over the amount of energy intake that can and may be fortified. The model was applied to derive safe maximum fortification levels for vitamin A, D, and folic acid. Based on these results the risk manager decided to legally allow voluntary fortification with vitamin D and folic acid up to a maximum level of 4.5 and 100 μg/100 kcal respectively.

Conclusion
The methodological improvements have resulted in higher accuracy for estimations of habitual intake distributions, which are essential for nutritional and food policy making. Furthermore, scenario analyses provide (under specific conditions) quantitative insight into proposed changes or areas such as maximum safe fortification levels. Several results and methods described are currently being used in research to assist Dutch and European food and nutrition policy making, which shows these methodologies are of immediate value to the practice of policy development and support.

Selenium beschermt tegen vrije radicalen : uit onderzoek blijken positieve effecten op de groei
Kierkels, T. ; Lugt, G.G. van der; Heuvelink, E. - \ 2011
Onder Glas 8 (2011)1. - p. 14 - 15.
glastuinbouw - groenteteelt - sporenelementen - selenium - seleniummeststoffen - plantenontwikkeling - paprika - voeding en gezondheid - groenten - greenhouse horticulture - vegetable growing - trace elements - selenium fertilizers - plant development - sweet peppers - nutrition and health - vegetables
Selenium speelt een rol bij verschillende processen in de plant, maar het is nog onduidelijk of het ook werkelijk essentieel is. Het kan de plant in elk geval beschermen tegen vrije radicalen. Maar het internationale onderzoek concentreert zich vooral op de vraag hoe je het seleniumgehalte in planten omhoog krijgt ten bate van mens en dier.
Effect of preventive supplementation with zinc and other micronutrients on malaria and diarrhoeal morbidity in African children
Veenemans, J. - \ 2011
Wageningen University. Promotor(en): Huub Savelkoul; A.M. Prentice. - s.n. - ISBN 9789085858294 - 214
zink - sporenelementen - voedselsupplementen - malaria - diarree - ziektepreventie - preventieve voeding - kinderen - tanzania - kenya - nadelige gevolgen - voedingsstoffentekorten - zinc - trace elements - food supplements - diarrhoea - disease prevention - preventive nutrition - children - adverse effects - nutrient deficiencies
Background: Zinc is important for innate and adaptive immune responses
to infection. Preventive zinc supplementation has been shown to reduce
the incidence of acute diarrhoea by 20%. Few trials have evaluated its effect
against malaria. Because trial results for both outcomes are inconsistent,
research priorities must shift from studies to measure efficacy to identifying
factors that determine the magnitude of the effect of zinc supplementation.
We hypothesized that protection by zinc supplementation depends on
concomitant supplementation with other nutrients.
Objectives: Specific objectives were: a) to assess the effect of supplementation
with zinc, alone or in combination with other nutrients, on the rates of malaria
(primary objective); b) to assess intervention effects on rates of diarrhoea and
other common diseases; c) to identify factors that determine the magnitude
of the effect of the interventions. Our studies also provided an opportunity to
assess effects of α+-thalassaemia on malaria and malaria-associated anaemia.
This haemoglobin disorder is highly prevalent in eastern Africa and that has
recently been reported to protect against severe malaria.
Methods: In a highly malaria-endemic area in rural Tanzania, we randomised
children (n=612) aged 6-60 months with height-for-age z-score ≤ –1.5 SD to
daily supplementation with: a) zinc, vitamins and other mineral elements
(‘multi-nutrients’); b) zinc; c) multi-nutrients without zinc; or d) placebo.
Those with Plasmodium infection at baseline were treated. Field staff
and participants were blinded to treatment. Sick children were detected
and evaluated in a research clinic. The primary outcome, an episode of
malaria, was pre-defined as current Plasmodium antigenaemia in children
with guardian-reported fever and any of the following: a) confirmed fever
(axillary temperature ≥ 37.5 °C), or b) unconfirmed fever with inflammation
(whole blood C-reactive protein concentrations ≥ 8 mg/L), separated by at
least 14 days from a previous malaria episode.
Results: The primary analysis included 1,572 episodes of malaria and 526
child-years of observation. The prevalence of zinc deficiency (plasma zinc
concentration < 9.9 μmol/mL) was 67% overall, and 60% in those without
inflammation (plasma C-reactive protein concentration < 8 mg/L). This
prevalence was dramatically reduced by zinc supplementation.
We found no evidence that concurrent supplementation with multi-nutrients
influenced the magnitude of the effect of zinc on rates of malaria or diarrhoea,
so that marginal effects will be presented in the remainder of this summary.
Although we found no evidence that zinc alone protected against malaria, it
reduced rates of diarrhoea by 24% (95% CI: 4%–40%) and of episodes of fever
without localising signs by 25% (4%–43%), two disorders with mutually
exclusive case definitions.
We found no effect of multi-nutrients on the overall rate of malaria episodes,
regardless the case definition used, but the effect estimate was likely
underestimated by children becoming asymptomatically infected in the
course of the intervention period. In the first 100 days of intervention, and
in the analysis of first events, supplementation with multi-nutrients, with
or without zinc, increased the hazard of malaria by one-third. In addition,
subgroup analysis indicated that this effect depended strongly on age and
iron status at baseline, with rates of episodes with parasite densities > 10,000
parasites/ μL increasing by 27 % (1%-61%) and 53% (11%–111%) in the
youngest children (6-17 months) and in children with iron deficiency, whilst
there was no evident effect in older children or those without iron deficiency
(p-values for interaction: 0.02 and 0.007).
Despite the increase in malaria rates, the children who had the lowest
haemoglobin concentrations during malaria (those aged 6-17 months)
were better able to maintain their haemoglobin concentrations when
having received multi-nutrients. Direct epidemiological evidence is
lacking, however, if and under what conditions the higher haemoglobin
concentrations during malaria (and expected reduced risk of death due to
severe malarial anemia) outweigh the possible increase in other potentially
lethal disease manifestations.
Multi-nutrient supplementation seemed to increase the rate of diarrhoea by
19% (–6% to 50%). Subgroup analysis indicated that this effect depended
on Giardia intestinalis infection at baseline (p-values for interaction: 0.03): in
those without multi-nutrients, infection was associated with a reduction in
rates of diarrhoea by 68% (34%-85%), whilst there was no evidence for such
protection in those receiving multi-nutrients. Similar effect modification was
found for fever without localizing signs.
Of 612 children in the trial, 50% had normal genotype, whilst 41% and 9%
were heterozygote and homozygous, respectively, for α+-thalassaemia. We
found no evidence of group differences in malaria rates between genotypes.
Subgroup analysis suggested, however, that the effect of α+-thalassemia
depended on age. Thus in children below 18 months, malaria rates were
increased by 30% (2%–65%) in heterozygotes, whereas they were decreased
by 20% (5%–32%) in older children (p-value for interaction: 0.001). Similar
patterns were found for homozygotes, even though estimates were less
precise due the smaller numbers of children in this age class. Based on data
from a pilot survey and a study in Kenya, we found that children with α+-
thalassaemia (particularly homozygotes) were protected against the decline in
haemoglobin concentration associated with mild to asymptomatic infections,
particularly when these infections were accompanied by inflammation.
Interpretation and conclusions for policies: We found no evidence that addition
of vitamins and other mineral elements increased the health benefits of zinc
supplements. The beneficial effects of zinc described in this thesis strengthen
the case for scaling up zinc interventions in deficient populations of African
children, without concerns that it will cause adverse effects due to malaria.
Multi-nutrient supplementation may be unsafe in malaria-endemic areas,
particularly in young children with iron deficiency. Thus the recommendation
by the World Health Organization that iron supplements should be
administered routinely to iron-deficient infants in settings with adequate
access to anti-malarial treatment is insufficiently supported by evidence and
should be reconsidered. Our results underscore that supplementation or
home fortification, even when targeting deficient subgroups in settings with
access to adequate primary care, should not be recommended in malariaendemic
areas until their safety has been demonstrated.
Honderden enzymen drijven op zink : zinkovermaat kan funest uitpakken
Kierkels, T. ; Heuvelink, E. - \ 2010
Onder Glas 7 (2010)3. - p. 18 - 19.
cultuurmethoden - plantenvoeding - sporenelementen - fotosynthese - voedingsstoffen - ph - zinkmeststoffen - mineraalovermaat - afwijkingen, planten - gewaskwaliteit - glastuinbouw - cultural methods - plant nutrition - trace elements - photosynthesis - nutrients - zinc fertilizers - mineral excess - plant disorders - crop quality - greenhouse horticulture
Zink is belangrijk voor het functioneren van honderden enzymen en andere eiwitten. Fotosynthese, vertaling van genen, aanmaak van eiwitten en hormonen drijven erop. Zinkgebrek leidt tot misvormingen en verkleuring. Een overmaat is funest voor de fotosynthese. Het element is gevoelig voor een te hoge pH
Nutritional interventions and blood pressure : role of specific micronutrients and other food components
Mierlo, L.A.J. van - \ 2010
Wageningen University. Promotor(en): Frans Kok, co-promotor(en): Marianne Geleijnse; P.L. Zock. - [S.l.] : S.n. - ISBN 9789085856900 - 187
bloeddruk - dieet - ziektepreventie - maatregel op voedingsgebied - sporenelementen - hypertensie - mineralen - blood pressure - diet - disease prevention - nutritional intervention - trace elements - hypertension - minerals
Background
Elevated blood pressure is an important risk factor for cardiovascular diseases (CVD). Modest reductions in blood pressure at the population level, as can be achieved by dietary and lifestyle changes, have a large impact on the burden of CVD. Blood pressure is regulated by several physiological mechanisms, including vascular endothelial function.

This thesis
The studies described in this thesis examined the potential effects of various micronutrients and other food components on blood pressure and endothelial function. The first aim was to assess the importance of selected minerals on population blood pressure levels and the second was to investigate the vascular effects of food components other than minerals that have recently attracted attention in the field of nutrition and blood pressure.
A review of 21 national surveys showed that current dietary potassium intakes are suboptimal (1.7-3.7 gram per day). We estimated that increasing intakes to the recommended level of 4.7 gram per day can reduce population systolic blood pressure by 2-3 mmHg in Western countries, this effect being similar to that which can be achieved by reducing current sodium intakes to recommended levels. Our meta-analysis of 40 randomized controlled intervention studies showed that increasing calcium intake by ~1200 mg per day significantly lowers systolic blood pressure by 2 mmHg and diastolic blood pressure by 1 mmHg. This effect tended to be stronger in populations with lower intakes (<800 mg per day). In an 8-week placebo controlled parallel study in 124 subjects with elevated blood pressure, we found no significant blood pressure lowering effects of skimmed milk enriched in potassium (1500 or 750 mg per daily serving) combined with calcium, magnesium, selenium, vitamin C and vitamin E. However, this study was not designed to detect reductions in systolic blood pressure of 2-3 mmHg, which are still relevant at the population level.
In two 4-week placebo controlled cross-over studies, in 162 subjects with untreated elevated blood pressure, we could not demonstrate an antihypertensive effect of a yogurt drink with lactotripeptides obtained by enzymatic hydrolysis (study 1: 10.2 mg per day; study 2: 4.6 mg per day plus 350 mg added potassium). In another 2-week placebo controlled cross-over study in 35 healthy males we found no consistent effect on endothelial function and blood pressure of ~800 mg polyphenols per day from either a wine-grape mix or grape seeds. Finally, a meta-analysis of 14 randomized controlled intervention studies showed that folic acid at a high dose (≥5000 g per day), which can not be attained with a regular diet, significantly improved flow-mediated dilation by 8%.

Conclusion
Adequate potassium and calcium intakes can play an important role in the prevention of hypertension at the population level. Lactotripeptides have no relevant effect on blood pressure in Caucasian populations. The potential of grape polyphenols and folic acid to improve endothelial function is limited.
Multiple actions are needed to lower blood pressure at the population level and reduce the burden of CVD. To improve intakes of potassium and calcium, public health measures should re-emphasize the intake of fruits, vegetables, and low-fat dairy products. Further optimization of mineral intakes, in particular reduction of sodium intake, requires collaborative actions of government and food industry.

UV-C preventief en curatief te gebruiken in glastuinbouw
Arkesteijn, M. ; Hofland-Zijlstra, J.D. - \ 2010
Onder Glas 7 (2010)2. - p. 18 - 19.
botrytis - sclerotinia - meeldauw - klimaatregeling - teeltsystemen - bloementeelt - gerbera jamesonii - schimmelbestrijding - belichting - sporenelementen - glastuinbouw - snijbloemen - mildews - air conditioning - cropping systems - floriculture - fungus control - illumination - trace elements - greenhouse horticulture - cut flowers
Botrytis is een lastig probleem. Belichting met UV-C kan een oplossing bieden. Luchtbehandeling met deze methode kan als hygiënemaatregel worden toegepast om de sporendruk te verlagen. Een UV-C robot door het groentegewas en een na-oogst-behandeling met dergelijk licht zijn mogelijke alternatieven voor chemische maatregelen. Alle drie zijn ze getest en geven ze positieve resultaten. De luchtbehandeling is nog niet praktijkrijp. Inmiddels loopt er een praktijkproef met gerberabloemen
Micronutrients, omega-3 fatty acids and cognitive performance in Indian schoolchildren
Eilander, J.H.C. - \ 2009
Wageningen University. Promotor(en): Frans Kok, co-promotor(en): S.J.M. Osendarp; S. Muthayya. - [S.l. : S.n. - ISBN 9789085854708 - 175
sporenelementen - meervoudig onverzadigde vetzuren - cognitieve ontwikkeling - mentale vaardigheid - minerale supplementen - fortificatie - ondervoeding - schoolkinderen - india - omega-3 vetzuren - kenvermogen - trace elements - polyenoic fatty acids - cognitive development - mental ability - mineral supplements - fortification - undernutrition - school children - omega-3 fatty acids - cognition
Evaluation of dietary diversity scores for assessment of micronutrient intake and food security in developing countries
Kennedy, G.L. - \ 2009
Wageningen University. Promotor(en): Frans Kok, co-promotor(en): Inge Brouwer. - [S.l. : S.n. - ISBN 9789085855255 - 157
sporenelementen - sporenelementtekorten - mineraaltekorten - voedselzekerheid - voedingsstoffenopname (mens en dier) - dieet - ontwikkelingslanden - trace elements - trace element deficiencies - mineral deficiencies - food security - nutrient intake - diet - developing countries
Micronutrient malnutrition and food insecurity are widespread global public health problems. Micronutrient deficiencies affect one-third of the global population. Household food insecurity, often results in monotonous diets, a contributing factor to malnutrition. Consuming a varied diet comprised of diversity across food groups is a recommended approach to achieving nutritional requirements. Many organizations promote the collection of information on dietary diversity to inform food security and nutritional assessments, but there is not an agreed upon set of indicators used for this purpose. Simple, standardized diet-based indicators are needed to assess, monitor and evaluate individual micronutrient intake and household food security. This thesis has a two-fold aim i) to examine relationships between dietary diversity and adequate intake of micronutrients and ii) to consider outstanding methodological questions. These include, determining an appropriate cut-point for (in)adequate intake of micronutrients from the diet and the effect of length of recall period on characterizing dietary patterns.

The association between probability of adequate micronutrient intake and individual dietary scores was determined by secondary analysis of data sets of non-breastfed Filipino children (n=2805, 2-5.9y), South African children (n=2200, 1-8y), and urban Malian women (n=102, 15-49y). Dietary diversity scores were positively and significantly correlated with intake of micronutrients, with correlation coefficients of 0.36, 0.63, and 0.33 in the Philippines, South Africa, and Mali respectively. Using a minimum quantity for a food group to count in the score improved the correlations to 0.44 in the Philippines and 0.48 in Mali. The best score cut-offs for a dichotomous indicator of inadequate intake of micronutrients were four and six food groups in South Africa and six in the Philippines. In Mali, five or more food groups was the best cut-off point for increased mean probability of micronutrient adequacy. In Mali dietary diversity scores using six and nine food groups had slightly higher correlations and indicator performance than scores based on thirteen or twenty-one food groups. Differences in household-level dietary patterns over one and seven day recall periods were tested through secondary analysis in Somalia (n=430 hh), Burkina Faso (n=3640 hh), Lao PDR (n=3913 hh) and Northern Uganda (n=1956 ). In Somalia, the median dietary diversity score was four for both a one day and seven day recall period. The main food groups consumed by fifty percent or more of households in the lowest dietary diversity tertile were cereals, sugar and oil for both recall periods. The dietary patterns based on food group consumption using score tertiles in Burkina Faso, Lao PDR and Northern Uganda were similar for one or seven days.

This thesis shows that dietary diversity scores are acceptable indicators of micronutrient intake from the diet. Requiring a minimum quantity of consumption for a food group to count in the score is better, but jeopardizes simplicity. The best cut-off for a dichotomous indicator differed across studies, but fell within the range of four to six food groups for predicting poor intake in children and five or more food groups to predict higher probability of adequate intake in women of reproductive age. Cost implications of misclassification and social unacceptability of false results are low for this indicator. For the purposes of characterizing dietary patterns of households at population level a one day recall period is sufficient. The simplicity of data collection and analysis of indicators of dietary diversity should enable more widespread and repeated collection of information on dietary intake in resource constrained, food insecure environments. Areas for further research include, the added value of assigning weights to food groups and studies in populations with higher average micronutrient intakes to better define an appropriate cut-point for a dichotomous indicator. It is recommended that dietary diversity scores be incorporated as monitoring and evaluation tools in food security and nutrition assessments at national level and below.

Zinkgehalte geit niet altijd op peil
Smolders, E.A.A. ; Eekeren, N.J.M. van; Govaerts, W. - \ 2009
V-focus 2009 (2009)12. - ISSN 1574-1575 - p. 19 - 21.
geitenhouderij - geiten - zink - biologische productie - begrazing - weiden - ruwvoer (forage) - sporenelementen - mineralen - vitaminen - biologische landbouw - goat keeping - goats - zinc - biological production - grazing - pastures - forage - trace elements - minerals - vitamins - organic farming
In de biologische geitenhouderij is weidegang verplicht en bevat het rantsoen ook in de stalperiode meer ruwvoer dan in de gangbare geitenhouderij. Ook wordt soms eigen graan gevoerd ter vervanging van commercieel krachtvoer. De voorziening met mineralen, spoorelementen en vitaminen moet daarbij bewuster gestuurd worden. Binnen het project Biogeit is op veertien biologische geitenbedrijven bloed onderzocht op gehalten aan mineralen en vitaminen. Ook is gekeken naar de gehalten in het rantsoen. In dit artikel staat zink centraal
Mineralen nodig voor goede vruchtbaarheid
Smolders, E.A.A. - \ 2009
BioKennis bericht Zuivel & rundvlees 14 (2009).
biologische landbouw - koeien - melkveehouderij - vruchtbaarheid - diervoeding - mineralen - sporenelementen - ruwvoer (forage) - graskuilvoer - selenium - zink - koper - organic farming - cows - dairy farming - fertility - animal nutrition - minerals - trace elements - forage - grass silage - zinc - copper
Alle mineralen, spoorelementen en vitaminen zijn belangrijk voor het goed functioneren van de koe. Hoe beter mineralen en spoorelementen in balans zijn in het rantsoen, hoe beter de benutting door het vee zal zijn. Er is echter een aantal elementen dat direct van belang is voor de vruchtbaarheid. In dit BioKennisbericht komen die elementen aan de orde. Daarbij leest u wat de kans dat er onvoldoende (of teveel) in het rantsoen aanwezig is en hoe problemen opgelost kunnen worden
Molybdeengebrek vermomt zich als stikstofgebrek: cruciale rol bij verschillende enzymen en de vorming van hormonen
Kierkels, T. ; Heuvelink, E. - \ 2009
Onder Glas 6 (2009)2. - p. 44 - 45.
tuinbouwbedrijven - molybdeen - sporenelementen - nitraatstikstof - stikstofgehalte - auxinen - plantengroeiregulatoren - abscisinezuur - groeiremmers - glastuinbouw - market gardens - molybdenum - trace elements - nitrate nitrogen - nitrogen content - auxins - plant growth regulators - abscisic acid - growth inhibitors - greenhouse horticulture
Molybdeen is het sporenelement waar de plant het minst van nodig heeft. Toch is het essentieel. Het speel een cruciale rol bij de benutting van nitraatstikstof. Een molybdeengebrek leist daarom tot een stikstofgebrek. Ook de vorming van de plantenhormonen auxine an abdscisinezuur is van molybdeen afhankelijk. Over dit element is nog veel onbekend
Aanvullende analyses prioritaire KRW-stoffen in vissen, aal en blankvoorn
Kotterman, M.J.J. - \ 2008
IJmuiden : IMARES (Rapport / Wageningen IMARES C117/08) - 20
palingen - rutilus rutilus - anguillidae - chemicaliën - sporenelementen - bemonsteren - kaderrichtlijn water - eels - chemicals - trace elements - sampling - water framework directive
In dit project zijn alen van negen locaties, bemonsterd in de late lente, geanalyseerd op de “nieuwe” KRW prioritaire stoffen; kortketenige gechloreerde paraffinen (SCCP short chain chlorinated paraffins), pentabromodiphenyl ethers (PBDE) en butyltinverbindingen (TBT). Blankvoorn van vijf overeenkomende locaties, bemonsterd in eind september, begin oktober, zijn geanalyseerd op dezelfde stoffen, inclusief de standaard-contaminanten van het MWTL-aal programma (PCB’s en OCP’s). De alen zijn geanalyseerd op basis van de visfilet, de blankvoorns zijn als hele vis geanalyseerd. In beide vissoorten zijn organische contaminanten goed meetbaar, afhankelijk van de locatie. In minder vervuilde gebieden zijn de concentraties soms beneden de rapportage-grens, vooral bij aal. In blankvoorn waren de concentraties van organische contaminanten op vetbasis soms hoger dan in de aal. Dit was vooral opvallend voor een aantal PBDE’s als ook TBT.
Indices to screen for grain yield and grain-zinc mass concentrations in aerobic rice at different soil-Zn levels
Jiang, W. ; Struik, P.C. ; Zhao, M. ; Keulen, H. van; Fan, T.Q. ; Stomph, T.J. - \ 2008
NJAS Wageningen Journal of Life Sciences 55 (2008)2. - ISSN 1573-5214 - p. 181 - 197.
oryza sativa - gewasopbrengst - zink - chemische samenstelling - mineraalgehalte - chemische bodemeigenschappen - korrels (granen) - sporenelementen - bioconcentratie - crop yield - zinc - chemical composition - mineral content - soil chemical properties - kernels - trace elements - bioconcentration - calcareous soil - field crops - in-field - efficiency - deficiency - wheat - genotypes - plants - tolerance - cultivars
Zinc is an important micronutrient for both crop growth and human nutrition. In rice production, yields are often reduced and Zn mass concentrations in the grains are often low when Zn is in short supply to the crop. This may result in malnutrition of people dependent on a rice-based diet. Plant breeding to enhance low-Zn tolerance might result in higher yields and nutritional quality but requires effective selection criteria embedded in physiological insight into the Zn husbandry of the crop and applicable in field evaluation of advanced breeding material or in screening of existing varieties. Using existing and newly developed low-Zn tolerance indices, this study presents the results of screening experiments carried out in high- and low-Zn soils. Sixteen accessions of aerobic rice were grown under greenhouse conditions to conceptualize the indices and 14 under field conditions to validate the indices. As the differences in soil-Zn levels in these experiments did not result in differences in grain yield, literature data were used from experiments where the soil-Zn level did have an effect on grain yield, to further check the validity of the indices. Several indices were applied to evaluate the genotypic low-Zn tolerance performance in attaining (relatively) high grain yield, high grain-Zn mass concentration, or both. The results indicate that the grain-Zn mass concentration efficiency index is different from the grain yield efficiency index and that the low-Zn tolerance indices identified superior genotypes best. Amongst the indices tested, the low-Zn tolerance index for grain yield and the low-Zn tolerance index for grain-Zn mass concentration were closely correlated with grain yield and grain-Zn mass concentration, respectively. Therefore, the low-Zn tolerance index for grain yield was effective in screening for high stability and high potential of grain yield, and the low-Zn tolerance index for grain-Zn mass concentration was effective for grain-Zn mass concentration under low and high soil-Zn conditions. Genotypic differences in yield and grain-Zn mass concentration were shown to be unrelated and therefore deserve separate attention in breeding programmes. Combining the low-Zn tolerance index for grain yield and the low-Zn tolerance index for grain-Zn mass concentration in a single low-Zn tolerance index was considered but did not appear to be superior to using the two indices separately.
Trace elements in animal production systems
Schlegel, P. ; Durosoy, S. ; Jongbloed, A.W. - \ 2008
Wageningen : Wageningen Academic Publishers - ISBN 9789086860616 - 347
sporenelementen - diervoeding - diervoedering - voer - dierlijke productie - dierlijke meststoffen - milieueffect - voedingsstoffenbehoeften - immuniteit - voedingsfysiologie - trace elements - animal nutrition - animal feeding - feeds - animal production - animal manures - environmental impact - nutrient requirements - immunity - nutrition physiology
This book deals with trace elements, such as cobalt, copper, iron, manganese, selenium and zinc which are essential to modern animal nutrition, but are increasingly detrimental to soil and water quality in today's globalized production. The goal in finding a sustainable balance between trace element use in animal nutrition and its impact on the environment is addressed.
Groeiremming als middel voor productie van visueel aantrekkelijke vaste planten : fosfaatvoeding als groeiremmer bij Salvia en Delphinium
Aendekerk, T.G.L. - \ 2007
Lisse : Praktijkonderzoek Plant & Omgeving, Boomkwekerij - 33
overblijvende planten - gewasproductie - fosformeststoffen - plantengroeiregulatoren - groeivertragers - vergelijkend onderzoek - sporenelementen - groeianalyse - perennials - crop production - phosphorus fertilizers - plant growth regulators - growth retardants - comparative research - trace elements - growth analysis
Het onderzoek in de teelt naar gedrongen kwalitatief goede vaste planten is in 2006 gestart op het PPO op de locatie Lisse. In dit onderzoek wordt getracht het gewenste fosfaatniveau vast te stellen voor Delphinium cultorum ‘Dark Blue/White Bee' en Salvia nemorosa ‘Blaukoenigin’ om de groei te beheersen. Fosfaatniveaus werden via het voedingswater met de druppelbevloeiing gegeven. De andere voedingselementen werden naar behoefte gegeven. Een nieuwe gecontroleerd vrijkomende meststof met een laag fosfaatgehalte (13+5+19+s) van Scotts BV werd parallel in het onderzoek mee genomen.
Measurement of trace elements in liver biopsy samples from cattle
Ouweltjes, W. ; Zeeuw, A.C. de; Moen, A. ; Counotte, G.H.M. - \ 2007
Tijdschrift voor Diergeneeskunde 132 (2007)3. - ISSN 0040-7453 - p. 76 - 83.
urine-analyse - diagnostische technieken - biopsie - diagnose - sporenelementen - rundvee - sporenelementtekorten - diervoeding - mineralenvoeding - lever - urine analysis - diagnostic techniques - biopsy - diagnosis - trace elements - cattle - trace element deficiencies - animal nutrition - mineral nutrition - liver - mineral status - beef-cattle - copper - zinc - supplementation - manganese - calves - iron
Serum, plasma, or urine samples are usually used for the measurement of the trace elements copper, zinc, iron, selenium, because these samples are easy to obtain; however, these samples are not always appropriate. For example, it is not possible to measure molybdenum, the major antagonist of copper, in blood or urine. Therefore measurement of trace elements in liver tissue is considered the gold standard. For the assessment of selenium the method of choice remains determination of glutathion peroxidase in erythrocytes and for the assessment of magnesium determination of magnesium in urine. We determined the accuracy and repeatability of measuring trace elements in liver biopsies and whole liver homogenates. The levels of trace elements measured were similar in both preparations (92% agreement). Liver biopsy in live animals is a relatively simple procedure but not common in the Netherlands. Reference levels of trace elements, classified as too low, low, adequate, high, and too high, were established on the basis of our research and information in the literature. In a second study we investigated the practical aspects of obtaining liver tissue samples and their use. Samples were collected from cattle on a commercial dairy farm. Liver biopsy provided additional information to that obtained from serum and urine samples. We prepared a biopsy protocol and a test package, which we tested on 14 farms where an imbalance of trace minerals was suspected. Biopsy samples taken from 4 to 6 animals revealed extreme levels of trace elements
Fotosynthese neemt af bij een overmaat aan zware metalen : oppassen voor kopervergiftiging bij gesloten kas
Kierkels, T. ; Heuvelink, E. - \ 2007
Onder Glas 4 (2007)2. - p. 52 - 53.
tuinbouw - fotosynthese - zware metalen - sporenelementen - plantenvoeding - kassen - irrigatie - hergebruik van water - plantenfysiologie - gesloten systemen - glastuinbouw - horticulture - photosynthesis - heavy metals - trace elements - plant nutrition - greenhouses - irrigation - water reuse - plant physiology - closed systems - greenhouse horticulture
Koper speelt een rol bij de fotosynthese en de versteviging van cellen. Een gebrek tast dan ook deze functies in de plant aan. Kopergebrek komt niet veel voor in de glastuinbouw. Eerder moet de tuinder oppassen voor een overmaat bij een toenemend gebruik van warmtewisselaars en hergebruik van condenswater. Een overmaat remt de fotosynthese. Een reden om een veilige grens voor de koperconcentratie in gietwater aan te houden en bij een verhoogd risico op koperaccumulatie het gehalte ook te monitoren
IJzer is essentieel voor de fotosynthese : ijzergebrek, de gebreksziekte die het vaakst voorkomt
Heuvelink, E. ; Kierkels, T. - \ 2006
Onder Glas 3 (2006)6/7. - p. 34 - 36.
plantenvoeding - voedingsstoffentekorten - sporenelementen - ijzer - fotosynthese - chelaten - rozen - glastuinbouw - snijbloemen - plant nutrition - nutrient deficiencies - trace elements - iron - photosynthesis - chelates - roses - greenhouse horticulture - cut flowers
Van alle gebreksziekten komt ijzergebrek het vaakst voor in de glastuinbouw. Bij een gebrek worden de jonge bladeren geel tussen de nerven. Dat komt omdat er te weinig chlorofyl gevormd wordt. IJzergebrek tast daarom direct het productievermogen van de plant aan. Ook tal van andere processen zijn ijzerafhankelijk. Veel tuinbouwgewassen - zoals roos - zijn gevoelig voor ijzergebrek. Door chelaten is de toediening niet meer zo lastig als vroeger. Maar er blijft een constante aandacht voor pH, concentratie van andere elementen en goede groeiomstandigheden nodig. Ook zonder gele bladeren kan er al productieverlies optreden
Trace metals in floodplain lake sediments : SEM/AVS as indicator of bioavailability and ecological effects
Griethuysen, C. van - \ 2006
Wageningen University. Promotor(en): Bart Koelmans. - [S.l. ] : S.n. - ISBN 9085043654 - 223
sporenelementen - metalen - stroomvlakten - meren - sediment - verontreinigende stoffen - waterverontreiniging - methodologie - ecologie - risicoschatting - waterkwaliteit - nederland - land van maas en waal - trace elements - metals - floodplains - lakes - pollutants - water pollution - methodology - ecology - risk assessment - water quality - netherlands
This thesis addresses the geochemical aspects of AVS (Acid Volatile Sulfide) and SEM (Simultaneously Extracted Metals) in floodplain lake sediment, its spatial distribution in floodplain lakes and dynamics over time, the link with effects on single species (bioassays), as well as the impact of excess SEM on the in situ benthic community, in one consistent methodological approach. Using this approach the SEM-AVS concept is thus evaluated on various levels from geochemical through ecotoxicology towards ecology. Furthermore, the aspect of spatial and temporal variability is addressed. For the case studies in the field, several floodplain lakes located in the floodplain area Afferdensche and Deestsche Waarden along the Waal branche of the Rhine were selected. Occasionally, this selection was extended towards other floodplain lakes along the Rhine branches. The main goal of this research is a) to explore the actual risks of trace metals to benthic communities in floodplain systems and b) to evaluate the SEM-AVS concept as a tool to assess bioavailable concentrations of trace metals in dynamic floodplain sediment
Borium belangrijk bij vatensysteem en de celstrekking van wortels
Heuvelink, E. ; Kierkels, T. - \ 2006
Onder Glas 3 (2006)3. - p. 20 - 21.
voedingsstoffentekorten - sporenelementen - borium - toepassing - afwijkingen, planten - symptomen - gevoeligheid - bemesting - glastuinbouw - nutrient deficiencies - trace elements - boron - application - plant disorders - symptoms - sensitivity - fertilizer application - greenhouse horticulture
Er is weinig bekend over de rol van het sporenelement borium in planten. Duidelijk is wel dat een tekort de celstrekking en de celdeling van de wortels remt. Het element is ook belangrijk bij de opbouw van de vaten, het transportsysteem voor water en mineralen in de plant. Een overmaat aan borium geeft verkleuring en vlekken die papierachtig indrogen in de oudste bladeren. Daarom is van belang met regelmaat analyses te laten uitvoeren
The effect of trace elements on the metabolism of methanogenic consortia
Jiang, B. - \ 2006
Wageningen University. Promotor(en): Fons Stams. - [S.l.] : S.n. - ISBN 9085043603 - 122
sporenelementen - metabolisme - methanol - anaërobe afbraak - methanobacteriaceae - trace elements - metabolism - anaerobic digestion
Invloed stikstofbemesting grasland op voorziening mineralen en spoorelementen rundvee
Remmelink, G.J. ; Holshof, G. ; Ouweltjes, W. - \ 2005
Lelystad : Animal Sciences Group (PraktijkRapport / Animal Sciences Group, Praktijkonderzoek : Rundvee ) - 70
stikstofmeststoffen - melkvee - graslanden - voedingsmineralen - sporenelementen - rundveevoeding - voedingsstoffenopname (mens en dier) - melkveehouderij - nederland - nitrogen fertilizers - dairy cattle - grasslands - dietary minerals - trace elements - cattle feeding - nutrient intake - dairy farming - netherlands
Het rantsoen op Nederlandse melkveebedrijven verandert. Boeren bemesten minder, gebruiken vaker klaver en het areaal beheers- en natuurland neemt toe. Bij een ruim ruwvoeraanbod neemt het aandeel krachtvoer af. Dit heeft consequenties voor de mineralen- en spoorelementenvoorziening van het rundvee. Tegen welke risico's lopen veehouders aan en welke mineralen en spoorelementen moet je zeker in de gaten houden? Het Praktijkonderzoek van de Animal Sciences Group heeft onderzoek op proefveld- en praktijkschaal uitgevoerd
Trace metal dynamics in methanol fed anaerobic granular sludge bed reactors
Zandvoort, M.H. - \ 2005
Wageningen University. Promotor(en): Gatze Lettinga, co-promotor(en): Piet Lens. - Wageningen : - ISBN 9085041465 - 208
anaërobe behandeling - rioolslib - metalen - sporenelementen - milieuafbraak - anaerobic treatment - sewage sludge - metals - trace elements - environmental degradation
Trace metals are essential for anaerobic microorganisms, because they are present as cofactor in many of their enzymes. Therefore anaerobic wastewater treatment systems using these microorganisms to perform biological conversions are dependent on these metals for their (optimal) performance. In practice these metals are supplied to the influent when they are absent or insufficiently present in the wastewater. This supply is generally not very rational. However, such a rational metal supply is desired in order to reduce the costs, to minimize the introduction into the environment and to maximize the biological activity. To achieve this insight, in the trace metal dynamics in anaerobic granular sludge bed reactors is required. This thesis therefore focuses on the retention, accumulation and release of trace metals in anaerobic granular sludge and the factors affecting these processes. Further the impact of metal presence/absence and dosing on the anaerobic conversion of methanol was addressed
Derivation of partition relationships to calculate Cd, Cu, Ni, Pb, Zn solubility and activity in soil solutions
Römkens, P.F.A.M. ; Groenenberg, J.E. ; Bonten, L.T.C. ; Vries, W. de; Bril, J. - \ 2004
Wageningen : Alterra (Alterra-report 305) - 75
bodemchemie - cadmium - koper - sporenelementen - nikkel - overgangselementen - lood - zink - soil chemistry - copper - trace elements - nickel - transition elements - lead - zinc
The distribution of heavy metals (Cd, Cu, Ni, Pb and Zn) between soil and soil solution was measured in more than 1400 soil - solution samples. These samples reflect the variability that occurs within the Netherlands and covers all major soil types. The distribution of metals between solid phase (adsorbed) and the soil solution was described using an extended Freundlich equation taking into account the impact of organic matter, clay, pH and Dissolved Organic Carbon. Apart from this, the impact of Fe and Al oxides was tested. The free ionic activities were also calculated from the data and partition relationships were derived for both total dissolved metal contenrations and free metal ion activities. The results show that an extended Freundlich equation is able to represent the wide range of total dissolved concentrations and free ion activities that are encountered in the database. For the metals Pb and Cu, the uncertainty in the predictions is, however, rather high. Further model improvement is required for these metals.
Cadmium en zink in de bodem en landbouwgewassen in de Kempen; onderzoek naar relatie tussen cadmium en zinkgehalte in de bodem en in het gewas in de gemeente Cranendonck
Rietra, R.P.J.J. ; Römkens, P.F.A.M. ; Japenga, J. - \ 2004
Wageningen : Alterra (Alterra-rapport 974) - 72
bodemverontreiniging - gewassen - sporenelementen - zink - cadmium - kempen - noord-brabant - soil pollution - crops - trace elements - zinc
In opdracht van stichting Actief Bodembeheer de Kempen is onderzoek gedaan naar de relatie tussen cadmium en zink in de bodem en in gewassen. Verspreid rondom Budel en Soerendonk zijn 44 locaties bezocht waarbij bodem en gewasmonsters zijn genomen van maïs, gras, biet of aardappel. Bepaald zijn de cadmium- en zinkgehalten van verschillende bodemhorizonten en gewasproducten.
Trace metal availability and effects on benthic community structure in floodplain lakes
Griethuysen, C. van; Baren, J. van; Peeters, E.T.H.M. ; Koelmans, A.A. - \ 2004
Environmental Toxicology and Chemistry 23 (2004)3. - ISSN 0730-7268 - p. 668 - 681.
meren - stroomvlakten - sporenelementen - waterorganismen - waterverontreiniging - rijn - waal - ijssel - aquatic organisms - water pollution - lakes - floodplains - trace elements - river rhine - river waal - river ijssel - acid-volatile sulfide - simultaneously extracted metals - macroinvertebrate community - contaminated sediments - cadmium accumulation - in-situ - invertebrates - toxicity - avs - bioavailability
Effects of contaminants on communities are difficult to assess and poorly understood. We analyzed in situ effects of trace metals and common environmental variables on benthic macroinvertebrate communities in floodplain lakes. Alternative measures of trace metal availability were evaluated, including total metals, metals normalized on organic carbon (OC) or clay, simultaneously extracted metals (SEM), combinations of SEM and acid-volatile sulfide (AVS), and metals accumulated by detritivore invertebrates (Oligochaeta). Accumulated metal concentrations correlated positively with sediment trace metals and negatively with surface water dissolved OC. Sixty-eight percent of the variation in benthic community composition was explained by a combination of 11 environmental variables, including sediment, water, and morphological characteristics with trace metals. Metals explained 2 to 6% of the community composition when SEM — AVS or individual SEM concentrations were regarded. In contrast, total, normalized, and accumulated metals were not significantly linked to community composition. We conclude that examination of SEM or SEM — AVS concentrations is useful for risk assessment of trace metals on the community level.
Het belang van mangaan-, magnesium- en zwavelbemesting in akkerbouw en vollegrondsgroenteteelt
Paauw, J.G.M. - \ 2003
Kennisakker.nl 2003 (2003)1 juli.
groenteteelt - groenten - sporenelementen - magnesiummeststoffen - mangaanmeststoffen - zwavelmeststoffen - mestbehoeftebepaling - vollegrondsteelt - bemesting - vollegrondsgroenten - akkerbouw - vegetable growing - vegetables - trace elements - magnesium fertilizers - manganese fertilizers - sulfur fertilizers - fertilizer requirement determination - outdoor cropping - fertilizer application - field vegetables - arable farming
Naar aanleiding van de behoefte in de praktijk om meer duidelijkheid over de noodzaak van bemesting met secundaire en sporenelementen is in dit project een bureaustudie uitgevoerd. Hierbij is gekozen voor magnesium, mangaan en zwavel bij een selecte groep akkerbouw- en vollegrondsgroentegewassen. Per voedingsstof is achtergrondinformatie gegeven over de functie ervan in de plant, beschikbaarheid in de bodem, gebreksziekten en bronnen van aan- en afvoer. Vervolgens zijn resultaten van veldproeven besproken van de laatste twee decennia en gereflecteerd aan de huidige bemestingsadviezen. Tenslotte is aangegeven in welke mate de huidige kennis voldoet om twijfels in de praktijk over bemesting met het betreffende element weg te kunnen nemen.
Mineralen en spoorelementen. Vooral in weideperiode extra aandacht nodig om goede mineralenvoorziening te waarborgen
Ouweltjes, W. ; Duinkerken, G. van - \ 2003
Veeteelt 20 (2003)7. - ISSN 0168-7565 - p. 24 - 25.
melkveehouderij - melkvee - rundveevoeding - voersamenstelling - mineralen - sporenelementen - voer - dairy farming - dairy cattle - cattle feeding - feeds - feed formulation - minerals - trace elements
Aandacht voor de betekenis van kalium, magnesium, koper, zwavel, molybdeen, zink en selenium in de voeding
Koper- en seleniumvoorziening op Koeien & Kansen-bedrijven voldoende
Smolders, G. - \ 2003
Praktijkkompas. Rundvee 17 (2003)3. - ISSN 1570-8586 - p. 26 - 27.
melkveehouderij - melkvee - melkveebedrijven - rundveevoeding - voer - voedingsstoffenbehoeften - voedingsstoffengehalte - voersamenstelling - selenium - koper - diergezondheid - sporenelementen - dairy farming - dairy cattle - dairy farms - cattle feeding - feeds - nutrient requirements - nutrient content - feed formulation - copper - animal health - trace elements
In 2002 bleek uit bloedonderzoek bij melkgevende koeien dat het gemiddelde kopergehalte goed was.
Acute respiratory infections in elderly people: the role of micronutrients and lifestyle
Graat, J.M. - \ 2003
Wageningen University. Promotor(en): Frans Kok; Evert Schouten. - [S.l.] : S.n. - ISBN 9058089223 - 152
ademhalingsziekten - influenza - verkoudheid - longontsteking - sporenelementen - vitaminen - vitamine e - levensstijl - ouderen - ouderdom - respiratory diseases - common cold - pneumonia - trace elements - vitamins - vitamin e - lifestyle - elderly - old age
Essential metal depletion in an anaerobic reactor
Osuna, M.B. ; Iza, J.M. ; Zandvoort, M.H. ; Lens, P.N.L. - \ 2003
Water Science and Technology 48 (2003)6. - ISSN 0273-1223 - p. 1 - 8.
anaërobe behandeling - afvalwaterbehandeling - vluchtige vetzuren - sporenelementen - slib - korrels - anaerobic treatment - waste water treatment - volatile fatty acids - trace elements - sludges - granules - trace-metals - heavy-metals - sludge - binding - sediments
The effect of the absence of trace elements on the conversion of a mixture of volatile fatty acids by a distillery anaerobic granular sludge was investigated. Two UASB reactors were operated under identical operational conditions except for the influent trace metal concentrations, during 140 days. Experiments were carried out in three periods, where different organic loading rates (OLR) were applied to the reactors
The effect of the absence of trace elements on the conversion of a mixture of volatile fatty acids by a distillery anaerobic granular sludge Was investigated. Two UASB reactors were operated under identical operational conditions except for the influent trace metal concentrations, during 140 days, Experiments were carried out in three periods, where different organic loading rates (OLR) were applied to the reactors. The total trace metal concentration steadily decreased at a rate of 48 mug metal/g TS.d in the deprived reactor (down to 35% of their initial value). In contrast, trace metals accumulated in granules present in the control reactor. At the end of the experiment, the COD removal efficiencies were 99% and 77% for the control and deprived reactors, respectively, due to the lack of propionate conversion. Cobalt sorption experiments were carried out in order to study its speciation, and its effects on the speciation of other metals as well. A paper mill wastewater treating granular sludge was also included in the study as a comparison. Results obtained showed that the principal metal forms normally associated with any sludge are a function of each soluble metal concentration in the system, and the characteristics of the particular sludge.
Effects of Micronutrients during Pregnancy and Early Infancy on Mental and Psychomotor Development
Verhoef, H. ; West, C.E. ; Bleichrodt, N. ; Dekker, P.H. ; Born, M.P. - \ 2003
In: Micronutrient Deficiencies in the First Months of Life / Delange, F.M., West, K.P. Jr, Basel : Karger (Nestlé Nutrition workshop series 52) - ISBN 3805575599 - p. 327 - 357.
zwangerschap - zuigelingen - maternale voeding - zuigelingenvoeding - sporenelementen - jodium - ijzer - voedingsstoffentekorten - cognitieve ontwikkeling - psychomotorische ontwikkeling - pregnancy - infants - maternal nutrition - infant nutrition - trace elements - iodine - iron - nutrient deficiencies - cognitive development - psychomotor development
The questions that are addressed in this chapter concern the extent to which a shortage of iodine and iron during fetal and infant development impairs mental development and the extent to which this impairment can be redressed by increasing the intake of these micronutrients
Zwavel en selenium: ook overdaad schaadt
Ouweltjes, W. ; Schils, R. - \ 2002
Praktijkkompas. Rundvee 16 (2002)3. - ISSN 1570-8586 - p. 30 - 31.
zwavel - selenium - melkvee - melkveehouderij - diervoedering - diervoeding - veevoeding - rundveevoeding - graskuilvoer - grassen - kuilvoerkwaliteit - diergezondheid - voersamenstelling - voedingsrantsoenen - voedingsbehoeften - voedingsstoornissen - voedingsstoffengehalte - voedingsstoffenbehoeften - sporenelementen - graslanden - sulfur - dairy cattle - dairy farming - animal feeding - animal nutrition - livestock feeding - cattle feeding - grass silage - grasses - silage quality - animal health - feed formulation - feed rations - feed requirements - nutritional disorders - nutrient content - nutrient requirements - trace elements - grasslands
In dit artikel wordt ingegaan op de zwavel- en seleniumvoorziening.
Kopervoorziening blijft punt van aandacht
Ouweltjes, W. ; Counotte, G. ; Dobbelaar, P. - \ 2002
Praktijkkompas. Rundvee 16 (2002)3. - ISSN 1570-8586 - p. 4 - 5.
koper - melkvee - melkveehouderij - diervoeding - diervoedering - veevoeding - rundveevoeding - graskuilvoer - grassen - kuilvoerkwaliteit - diergezondheid - voersamenstelling - voedingsstoffengehalte - voedingsbehoeften - voedingsstoffenbehoeften - voedingsrantsoenen - voedingsstoornissen - sporenelementen - graslanden - copper - dairy cattle - dairy farming - animal nutrition - animal feeding - livestock feeding - cattle feeding - grass silage - grasses - silage quality - animal health - feed formulation - nutrient content - feed requirements - nutrient requirements - feed rations - nutritional disorders - trace elements - grasslands
Zowel een tekort als een overmaat is schadelijk. Naast het kopergehalte in het rantsoen is de benutting een belangrijke factor.
Sorption (kinetic and capacity) and desorption of trace elements in volcanic soils of Italy and the Azores
Tanneberg, H. ; Jahn, R. ; Meijer, E.L. - \ 2001
In: Volcanic soils : properties, processes and land use, international workshop (abstracts) - p. 58 - 59.
vulkanische gronden - bodemchemie - adsorptie - sporenelementen - italië - volcanic soils - soil chemistry - adsorption - trace elements - italy
Micronutrient deficiencies in South African infants and the effect of a micronutrient-fortified complementary food on their nutritional status, growth and development
Oelofse, A. - \ 2001
Wageningen University. Promotor(en): J.G.A.J. Hautvast; A.J.S. Benade; Joop van Raaij; J.J.M. Tolboom. - S.l. : S.n. - ISBN 9789058084989 - 133
zuigelingenvoedering - sporenelementen - voedingsstoffentekorten - kinderen - voedingstoestand - voedsel - aanvullende voedingsprogramma's - groei - zuid-afrika - infant feeding - trace elements - nutrient deficiencies - children - nutritional state - food - supplemental feeding programs - growth - south africa
<p>Consequences of micronutrient deficiencies in infants often include linear growth retardation, impaired psychomotor development and reduced appetite. Fortification of complementary food is one way of addressing micronutrient deficiencies in this age group. Knowledge about these deficiencies, food consumption patterns and appetite in infants is essential in planning micronutrient fortification intervention studies. In this thesis four studies are described, two of which studied the prevalence of micronutrient deficiency and linear growth retardation in rural and urban disadvantaged South African infants. The third study determined the adequacy of the appetite of infants at the age of 6 months. The final study is an intervention study with the aim to study the effect of a micronutrient fortified complementary food on the nutritional status, growth and development of 6-12-month-old poor urban infants.</p><p>The results from the first two studies showed a high prevalence of vitamin A, iron and zinc deficiency in both rural and urban infants. The low socio-economic status of the urban community and sub-optimal feeding practices may explain the similarity of deficiencies observed between rural and urban infants. The third study demonstrates that appetite was adequate in infants at the age of 6 months and not yet affected by micronutrient deficiencies. The consumption of a micronutrient-fortified complementary food appeared to reduce the decline in both serum retinol and iron concentrations in the experimental group. No effect was observed on serum zinc concentration, linear growth and psychomotor development.</p><p>In conclusion, the findings of this study demonstrate similar levels of nutritional deficiencies in both poor urban and rural children. Significant differences between urban disadvantaged coloured and black infants with respect to micronutrient deficiencies and linear growth exist. This highlights the importance of including assessment of micronutrient status in addition to anthropometric measurements when assessing nutritional status. The observation of an adequate appetite in infants at the age of 6 months is important for the introduction of micronutrient-fortified complementary food. The observed positive effect of a micronutrient-fortified complementary food on serum retinol and iron concentrations in 6-12-month-old infants should be investigated further.</p>
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