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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    The transcriptome as early marker of diet-related health : evidence in energy restriction studies in humans
    Bussel, Inge P.G. van - \ 2017
    Wageningen University. Promotor(en): Sander Kersten, co-promotor(en): Lydia Afman. - Wageningen : Wageningen University - ISBN 9789463430678 - 194
    energy restricted diets - energy intake - gene expression - genomes - proteins - endurance - food composition - human nutrition research - energiearme diëten - energieopname - genexpressie - genomen - eiwitten - uithoudingsvermogen - voedselsamenstelling - voedingsonderzoek bij de mens

    Background: Nutrition research is facing several challenges with respect to finding diet related health effects. The effects of nutrition on health are subtle, show high interindividual variations in response, and can take long before they become visual. Recently, the definition of health has been redefined as an organism’s ability to adapt to challenges and ‘this definition’ can be extended to metabolic health. In the metabolic context the ability to adapt has been named ‘phenotypic flexibility’. A potential new tool to magnify the effects of diet on health is the application of challenge tests. Combined with a comprehensive tool such as transcriptomics, the study of challenge tests before and after an intervention might be able to test a change in phenotypic flexibility. A dietary intervention well-known to improve health through weight loss is energy restriction (ER). ER can be used as a model to examine the potential of challenge tests in combination with transcriptomics to magnify diet-induced effects on health. As opposed to ER, caloric restriction (CR) is a reduction in energy intake aimed at improving health and life span in non-obese subjects and not directly aimed at weight loss. In this thesis, we aimed to investigate the use of the transcriptome as an early and sensitive marker of diet-related health.

    Methods: First we studied the consequences of age on the effects of CR on the peripheral blood mononuclear cells (PBMCs) transcriptome. For that purpose, we compared the changes in gene expression in PBMCs from old men with the changes in gene expression in PBMCs from young men upon three weeks of 30% CR. To study the effect of a change in dietary composition during ER, we compared the changes in gene expression upon a 12 weeks high protein 25% ER diet with the changes in gene expression upon a 12 weeks normal protein 25% ER diet in white adipose tissue (WAT). Next, we investigated the added value of measuring the PBMC transcriptome during challenge tests compared to measuring the PBMC transcriptome in the fasted state to magnify the effects of ER on health. This was investigated by measuring the changes in gene expression upon an oral glucose tolerance test (OGTT) and upon a mixed meal test (MMT), both before and after 12 weeks of 20% ER. Finally, we determined the differences between a challenge test consisting of glucose alone, the OGTT, or consisting of glucose plus other macronutrients, the MMT, on the PBMC transcriptome in diet-related health.

    Results: We observed that the transcriptome of PBMCs of healthy young men had a higher responsiveness in immune response pathways compared to the transcriptome of PBMCs of aged men upon CR (chapter 2). Also, we showed that upon a normal protein-ER diet the transcriptome of WAT showed a decrease in pathways involved in immune response and inflammasome, whereas no such effect was found upon a high protein-ER diet. These effect were observed while parameters such as weight loss, glucose, and waist circumference did not change due to the different protein quantities (chapter 3). 12 weeks of 20% ER was shown to increase phenotypic flexibility as reflected by a faster and more pronounced downregulation of OXPHOS, cell adhesion, and DNA replication during the OGTT compared to the control diet (chapter 4). Finally, two challenge tests consisting of either glucose (OGTT) or glucose plus fat and protein (MMT), were shown to result in a larger overlap than difference in the changes in gene expression of PBMCs (chapter 5).

    Conclusions: Based on the differential changes in gene expression upon CR at different ages, we concluded that age is an important modulator in the response to CR. As a high protein ER diet induced transcriptional changes seemed to reflect less beneficial health effects than a normal protein ER diet we concluded that the diet composition is important in the health-effect of ER as measured by the transcriptome. Based on the faster PBMCs changes in gene expression during an OGTT upon 12 weeks of 20% ER, we concluded that the PBMC transcriptome combined with a challenge test can reflect changes in phenotypic flexibility. This makes challenge tests a suitable tool to study diet-related health effects. Finally, based on the changes in gene expression of the MMT and OGTT, we conclude that glucose in a challenge test is the main denominator of the postprandial changes in gene expression in the first two hours. Overall, these results lead to the conclusion that the transcriptome, especially in combination with challenges test, can be used as an early marker of diet-related health. The direct relation to health still needs to be investigated, but the possibility to use the transcriptome as an early marker of diet-related health gives rise to a better understanding of the effects of nutrition on health.

    Measurement errors in dietary assessment using duplicate portions as reference method
    Trijsburg, L.E. - \ 2016
    Wageningen University. Promotor(en): Pieter van 't Veer; Anouk Geelen; Jeanne de Vries. - Wageningen : Wageningen University - ISBN 9789462576421 - 128
    diet studies - nutritional assessment - questionnaires - reference standards - correction factors - validity - body mass index - regression analysis - food intake - food - protein - potassium - sodium - energy intake - methodology - dieetstudies - voedingstoestandbepaling - vragenlijsten - referentienormen - correctiefactoren - geldigheid - quetelet index - regressieanalyse - voedselopname - voedsel - eiwit - kalium - natrium - energieopname - methodologie

    Measurement errors in dietary assessment using duplicate portions as reference method

    Laura Trijsburg

    Background: As Food Frequency Questionnaires (FFQs) are subject to measurement error, associations between self-reported intake by FFQ and outcome measures should be corrected for measurement error with data from a reference method. Whether the correction is adequate depends on the characteristics of the reference method used in the validation study. The duplicate portion method (DP), compared to the often used 24h recall (24hR), seems a promising reference method as correlated errors between FFQ and DP, such as memory bias, errors in portion size estimations and food composition databases, are not expected.

    Aim: This thesis aimed to determine the validity of the DP compared to the 24hR as a reference method for FFQ validation. The second aim was to explore the validity of nutrient densities for DP, 24hR and FFQ. The third aim was to determine the factors associated with misreporting of energy, protein and potassium as estimated by DP, 24hR and FFQ.

    Methods: Within the DuPLO-study, a Dutch validation study which is part of the NQplus study, two DPs, two FFQs, two blood and urinary biomarkers and one to fifteen 24hRs (web-based and/or telephone-based) were collected in 198 subjects, within 1.5 years. Also, one or two doubly labelled water measurements were available for 69 participants. Multivariate measurement error models were used to assess proportional scaling bias, error correlations with the FFQ, validity coefficients and attenuation factors. Furthermore linear regression analysis was used to determine the association between misreporting and various factors.

    Results: The DP was less influenced by proportional scaling bias, had lower correlated errors with the FFQ and showed higher attenuation factors than the 24hR for potassium, sodium and protein. Also, the DP seemed a better reference method than the 24hR for the assessment of validity coefficients for the FFQ for various fatty acids. The attenuation factors for the FFQ, using either the DP or 24hR as reference method, agreed reasonably well. Furthermore, the DP showed, when using plasma fatty acids as reference, slightly better ranking of participants according to their intake of n-3 fatty acids (0.33) and the n‑3/LA ratio (0.34) than the 24hR (0.22 and 0.24, respectively). Less group level bias was observed for protein and sodium densities compared to their absolute intakes for FFQ, 24hR and DP, but not for potassium. Overall the validity coefficients and attenuation factors for DP, 24hR and FFQ did not improve for nutrient densities compared to absolute intakes, except for the attenuation factor for sodium density. Lastly, BMI proved to be the most consistent determinant associated with misreporting (group level bias) of energy, protein and potassium for DP, 24hR and FFQ. Men tended to underreport protein by the DP, FFQ and 24hR and persons of older age underreported potassium but only by the 24hR and FFQ. Other explorative determinants did not show a consistent association with misreporting of energy or nutrients by the different dietary assessment methods.

    Conclusion: With respect to error correlations and attenuation factors the DP performed slightly better than the 24hR as a reference method for validating FFQs in epidemiological research. Furthermore, the use of nutrient densities does not necessarily improve the validity of the dietary intake estimates from DP, 24hR and FFQ. Moreover, it was shown that BMI is an important determinant of misreporting of energy, protein and potassium for these three assessment methods.

    Metabolic adaptation of white adipose tissue to nutritional and environmental challenges
    Hoevenaars, F.P.M. - \ 2014
    Wageningen University. Promotor(en): Jaap Keijer, co-promotor(en): Evert van Schothorst. - Wageningen : Wageningen University - ISBN 9789461739162 - 166
    muizen - vetweefsel - metabolisme - adaptatiefysiologie - voeding - milieufactoren - obesitas - energieopname - zuurstoftekort - ontsteking - voedingsfysiologie - diermodellen - mice - adipose tissue - metabolism - adaptation physiology - nutrition - environmental factors - obesity - energy intake - oxygen deficiency - inflammation - nutrition physiology - animal models

    Summary of main findings

    When adipose tissue is present in excessive amounts, as in obesity, it predisposes to a number of pathologies. Obesity is a complex, multifactorial condition as it influences many endogenous genetic, endocrine, and inflammatory pathways. Excess dietary intake is one of the important factors which are responsible for the increasing prevalence of obesity. For the understanding of the reciprocity between

    consumed diet and excessive amounts of adipose tissue, it is essential to investigate underlying functioning. In this thesis, I have addressed three important aspects that play a role in the development of diet induced obesity and its pathologies with a focus on adipose tissue metabolism.

    Does a body weight set-point exist?

    How is the diet-induced metabolic response affected by housing at


    Does oxygen restriction induce inflammation in white adipose tissue?

    The first aspect investigated was the existence of a body weight set point. A body weight set point is defined as a pre-determined or preferred level of body weight which is preserved by an internal feedback control mechanism. In chapter 2, a dietary intervention with none, one, or two diet alterations of purified diets was performed in C57BL/6J mice to investigate if a long lasting effect on body weight persistence was present. Diets contained equal protein content and source of ingredients but differed in the fat-to-sugar ratio. Therefore, energy content and amount of fat was different for either the low fat diet or the high fat. In the intervention the last consumed diet of the mice determined energy intake, energy expenditure, body weight, body fat stores, circulating hormones and metabolites. These data support the settling point theory as body weight and metabolic parameters ‘settle’ based on current energetic input and output and do not support the set point theory. Next to that it underlines the importance of diet choice in intervention studies focusing on aspects on the crossroads of nutrition and physiology.

    In chapter 3adipose tissue physiology and molecular regulation was further investigated by exposure to more metabolic stress in the form of a weight loss challenge with different purified diets. Diet-induced obese C57BL/6J mice were fed a high fat diet restricted to 70% intake of previous ad libitum high fat diet

    intake or they were changed to ad libitum low fat diet for 5 weeks. Beneficial effects were seen in both interventions regarding physiological parameters. However, molecular parameters in white adipose tissue differed between the two restriction interventions, with increased activation of mitochondrial carbohydrate and fat metabolism in high fat diet restricted mice. When extrapolated to the human

    situation this may suggest that a reduction of portion size is the best method for weight loss.

    It is standard practice to house mice at ambient temperature during physiological intervention studies. Unfortunately mice are then exposed to a temperature below their thermal neutral zone. This implies that their metabolism is chronically increased which is known to influence study outcomes. In chapter 4the second question; “how is the diet-induced metabolic response affected by housing at thermoneutrality?”was investigated. A 14-week dietary intervention with two semi-purified diets, a

    low fat diet and a moderately high fat diet, was performed at 28°C in C57BL/6J mice. This resulted in a large diet-induced difference in bodyweight, adipose tissue mass, adipocyte size, and serum leptin level. But no differential effects of the diets were seen on serum glucose, free fatty acids, triacylglycerides, insulin, a panel of cardiovascular markers, and a number of (metabolic) parameters in liver and muscle.

    Although adipose tissue mass and adipocyte size was increased significantly, there was no sign of inflammation or dysfunction in the adipose tissue. This study suggests that diet-induced obesity of C57BL/6J mice at thermoneutrality results in a suitable model for the metabolically ‘healthy’ obese (people who are significantly overweight but show none of the usual metabolic problems). Next to that, this study emphasizes the importance of consideration and control of housing temperature for mice, as it has profound effects on study outcomes.

    The third and last question investigated was if oxygen restriction is able to induce inflammation in white adipose tissue. There is substantial evidence that white adipose tissue becomes hypoxic when excessively enlarged. Due to fast expansion of white adipose tissue the vasculature is not able to keep pace with growth. Next to that, adipocytes are able to increase in size beyond the limit of oxygen diffusion. To investigate if hypoxia was able to induce inflammation in white adipose tissue, the model for healthy obese adipocytes (developed in chapter 4) was used and exposed to ambient oxygen restriction (13%) to challenge adipose tissue metabolism. This resulted in the presence of systemic oxygen restriction as shown by increased levels of hemoglobin and hematocrit. Furthermore a switch to glycolytic metabolism, which is indicative for tissue hypoxia, was present. No differences in adipose tissue macrophage infiltration (as marker for inflammation) were found. But, serum branched chain amino acids and adipokines were affected. Branched chain amino acids were increased in mice exposed to oxygen restriction which shows resemblance with findings in humans where increased levels were found in lean versus obese people. The peptide hormone adiponectin was increased in serum, without differences in WAT expression. On the other hand, the peptide hormones CCDC3 and CCK showed decreased transcript levels in white adipose tissue without significant change in serum levels, although for CCDC3 a trend was seen. Together these results suggest that oxygen restriction does not induce inflammation in adipose tissue. However, it does affect adipokine regulation.

    After performing these studies it was clear that composition of the diet has a major influence on outcome parameters of physiological studies as shown in chapter 2. To compare functional effects of different nutrients, it is important to use standardized purified diets. Not only the experimental intervention diet is of importance but also the reference control diet can influence outcomes. For example, when an intervention is performed with a high fat purified diet and the reference diet is chow this will lead to a difficult comparison. The content of chow is variable as it is grain or cereal based (ground corn, ground oats alfalfa meal, soybean meal and ground wheat). Nutritional adequacy is ensured by addition of vitamins, minerals, and fat. However, the exact amount of the various ingredients is frequently kept secret by the manufacturer. Next to that, due to the plant based origin of chow it will contain nutritive (protein, carbohydrate, fat) components but also non-nutritive components (phytochemicals). The content of the chow diet will vary from batch to batch as the nutritive and nonnutritive value will change between harvests. When using a chow reference diet in

    comparison to a purified diet you will never know exactly what you are comparing, i.e. difference in amino acids or effects of phytochemicals etc. Therefore, a reference diet for physiology was designed (chapter 6) to improve comparison of study outcomes and to increase efficiency of resources and material. A key feature of the diet is the fixed protein concentration, which allows for an exchange of carbohydrate and fat in a high fat version of the diet.

    To conclude, the work presented in this thesis provides clear insight in factors that are of importance for improvement of translatability of mouse studies to the human situation. It was shown that when investigating the weight balance many parameters, i.e. genetics, metabolic rate, environmental factors like ambient housing temperature and light and cognitive behavior, besides the diet and its composition are able to influence the outcome parameters. As most mouse experiments are performed

    in a fixed environment with no choices of food and a standard temperature set to 22°C. This is clearly not reflective of humans under free living conditions. However, these fixed conditions are able to result in experiments that unravel underlying mechanisms of weight balance, which form the basis for discovering a solution to the obesity epidemic.

    Feed intake and oxygen consumption in fish
    Subramanian, S. - \ 2013
    Wageningen University. Promotor(en): Johan Verreth, co-promotor(en): Johan Schrama; S.J. Kaushik; I. Geurden. - Wageningen : Wageningen UR - ISBN 9789461737571 - 163
    vissen - voeropname - zuurstofconsumptie - energieopname - voer - samenstelling - energiemetabolisme - macronutriënten - visvoeding - visteelt - aquacultuur - voedingsfysiologie - fishes - feed intake - oxygen consumption - energy intake - feeds - composition - energy metabolism - macronutrients - fish feeding - fish culture - aquaculture - nutrition physiology

    In fish, the voluntary feed intake is influenced by dietary, environmental and/or physiological factors. It is well known that under hypoxia the concentration of oxygen in the water (DO) determines the feed intake of fish. However at non-limiting water DO levels (normoxia), several other mechanisms might play a role in feed intake regulation. Under hypoxia feed intake and oxygen consumption are interrelated. In this thesis we proposed the ‘oxystatic’ concept of feed intake regulation, which states that even at normoxia and in the absence of other constraints, the long term (weeks) voluntary feed intake of fish can be constrained by a set-point value of oxygen consumption. Dietary macronutrient composition affects the ‘dietary oxygen demand’ (i.e., amount of O2 consumed per unit of feed). This oxystatic concept implies that fish fed to satiation with diets differing in ‘dietary oxygen demand’ (mg O2/ g or kJ feed) will have a different digestible energy intake but a similar oxygen consumption. The validity of the oxystatic concept was assessed in two species, Nile tilapia and rainbow trout. These fish were fed diets which had large contrasts in nutrient composition (i.e., protein to energy ratio; type of the non-protein energy source (starch vs. fat); amino acid composition) in order to create contrasts in dietary oxygen demand. In all conducted studies with both species, the digestible energy intake was affected by the diet composition. However, in some studies oxygen consumption was similar and in others it differed between the diets, which respectively supports and contradicts the oxystatic concept. In all studies with both species, the digestible energy intake of tilapia and trout was negatively related to dietary oxygen demand and positively related to efficiency of oxygen utilization for energy retention. Furthermore it was observed in tilapia that the within-day variation in feed intake was affected by dietary macronutrient composition. The variation in within-day feed intake was related to pre-feeding oxygen levels. Based on the combined results, it is suggested that even at normoxia voluntary feed intake in fish is limited/determined by oxygen consumption and/or the oxidative metabolism. Overall, the oxystatic concept appears to be valid for certain conditions, but its generic application remains questionable. Yet, the oxystatic concept enables the combination of dietary, environmental and fish factors into one concept. Further it provides a conceptual insight for better understanding of feed intake regulation in fish.

    Dietary fibres and appetite : comparing apples and oranges?
    Wanders, A.J. - \ 2013
    Wageningen University. Promotor(en): Edith Feskens; Kees de Graaf, co-promotor(en): Monica Mars. - S.l. : s.n. - ISBN 9789461735034 - 166
    voedingsvezels - eetlust - eetlustcontrole - verzadigdheid - energieopname - lichaamsgewicht - viscositeit - dietary fibres - appetite - appetite control - satiety - energy intake - body weight - viscosity

    Keywords: dietary fibre, satiation, satiety, appetite, energy intake, body weight, viscosity, eating time, gastric emptying, fermentation.

    Background and objective:Dietary fibre can contribute in the prevention of overweight and obesity. However, different classes of dietary fibre may have different effects on appetite and energy intake regulation. The aim of this thesis was to investigate the effect of different dietary fibre classes on appetite, and its underlying mechanisms. Both acute and long term effects of dietary fibre classes were explored by diverse study designs, comprising a systematic review, three intervention studies and an observational study.

    Methods:First, we systematically reviewed available literature on the relationship between dietary fibre types, satiety, acute and long term energy intake and body weight. Next, in two intervention studies we investigated whether bulking, viscous, and gel forming properties of fibre could be related to satiation (n=121) or satiety (n=29), and whether fibre consumed in different food matrices could be related to satiety (n=29). Then, in a third intervention study (n=32), the role of acute and long term exposure (16 days) to gel forming fibre on satiety and energy intake was explored. Finally, long term (6.4 year) associations between the intake of dietary fibre classes and change in body weight were studied in an elderly population-based prospective cohort (n=1,859).

    Results:The literature review of studies in acute settings showed that dietary fibres with viscous properties and dietary fibres consumed in a liquid food matrix increased satiety and lowered subsequent energy intake. In the intervention studies we observed that foods containing a high-dose of gel forming fibre induced earlier satiation and increased satiety. Foods containing bulking and viscous fibres did not affect satiation or satiety. We observed that the earlier satiation and increased satiety were likely mediated by the increased time that was needed to eat the foods. Satiety, but not earlier satiation, was related to a slowed down gastric emptying rate.

    The literature review of studies on long term effects indicated that dietary fibre may lower energy intake and body weight, and that not all dietary fibre types are equally effective. Long term changes could, however, not be associated with viscosity, solubility, fermentability or with food matrix properties. In the intervention study we found that a gelled fibre persistently increased satiety compared to control, but did not decrease energy intake or body weight. In the prospective cohort study, a higher intake of total fibre, fibre from different food sources and fibre types were not associated with changes in body weight or waist circumference, although in general inverse associations were observed.

    Conclusions:We conclude that fibre classes that are hydrated and thickened result in earlier satiation and increased satiety. These effects are likely mediated by an increased oro-sensory exposure time and a slowed down gastric emptying rate. Dietary fibres may decrease long term energy intake and body weight, yet, we were not able to associate the effects with specific dietary fibre classes or underlying mechanisms.

    Food characteristics and dietary intake : the role taste, eating rate and energy density
    Viskaal - van Dongen, M. - \ 2012
    Wageningen University. Promotor(en): Kees de Graaf; Frans Kok. - S.l. : s.n. - ISBN 9789461732507 - 139
    voedselopname - energieopname - smaak - eetsnelheden - voedingsgedrag - voedselconsumptie - energiegehalte - food intake - energy intake - taste - eating rates - feeding behaviour - food consumption - energy content

    The increases in obesity prevalence coincide with changes in our food environment, such as an increased consumption of processed, energy dense foods. This suggests that the foods we consume are at least partly responsible for the obesity epidemic. The aim of this thesis is therefore to investigate food characteristics, with the focus on taste, eating rate and energy density, and their relation to dietary intake.

    Taste is studied in two respects. First, the contribution of taste qualities to the diet is investigated, using the Food Consumption Survey 2003. Foods are classified according to their predominant taste (sweet, salty or savoury, sour, bitter or neutral). Energy intake of the foods within taste categories is assessed, showing that the largest part (34%) of the daily energy intake originates from sweet foods. Second, it is investigated whether taste, which is supposed to be a nutrient sensor, can fulfil this function within the current diet. Intensities of the five basic tastes of 50 commonly consumed foods are therefore assessed and associated with the nutrient content. Positive associations are found between sweetness and mono- & disaccharides and between both saltiness and savouriness and sodium and protein. The associations are less pronounced in highly processed foods, which suggests that in these foods the ability to sense nutrient content based on taste is limited. The influences of an incongruence between sensory properties and nutrient content are also investigated, byexamining the effects of fat perceptionon energy intake. We demonstrated that energy intake is almost 10% lower in case of visible fats compared to hidden fats, suggesting that hidden fats may contribute to overconsumption.

    Eating rateseems to be associated with food intake. The contribution of eating rate to the diet is investigated, using the Food Consumption Survey 2003. Foods are classified into one of four eating rate categories, and energy intake of the foods within each category is assessed. Results demonstrate that foods with slow calories (kJ/min) provide 10%, whereas foods with fast calories provide 37% to the daily energy intake. So in the current diet, the consumption of foods with a high eating rate is high. The effects of eating rate on intake are also investigated, showing that eatingrate is positively associated with food and energy intake. People may therefore be at risk of overconsumption, when consuming foods with a high eating rate.

    Consuming energy dense snacks is often blamed for affecting energy balance, but findings are inconclusive. Therefore, effects of snack consumption on body weight are investigated. No changes in body weight are observed after 8 weeks, when energy density of snacks was either low or high. This suggests that consuming snacks does not necessarily contribute to weight gain, at least in normal-weight young adults.

    In conclusion,when taste and other sensory properties do not accurately reflect the nutrient content, which applies particularly to highly processed foods, this may lead to high food intakes. In addition, a large part of the daily energy intake originates from foods with a high eating rate, which stimulates food and energy intake. So the high eating rate of the foods in the current diet may be responsible for overconsumption. These findings may be helpful in following the recommendations of the Nutrition Centre to lose weight. Last, even though we did not find evidence that consuming energy dense snacks results in weight gain, the advice should nevertheless be to limit the intake of energy dense foods, at least until evidence becomes more conclusive.

    Invloed van drie dagen kunstmelk na spenen en van voersamenstelling op energieopname en Streptococcus suis verschijnselen bij biggen = Effect of three days milk supply and of feed composition after weaning on energy intake and clinical signs of Streptococcus suis in piglets
    Peet-Schwering, C.M.C. van der; Troquet, L.M.P. ; Binnendijk, G.P. ; Diepen, J.T.M. van; Raymakers, R. - \ 2012
    Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 577)
    varkenshouderij - biggen - biggenvoeding - speenleeftijd - energieopname - streptococcus suis - diergezondheid - pig farming - piglets - piglet feeding - age at weaning - energy intake - streptococcus suis - animal health
    At Swine Innovation Centre Sterksel it was investigated whether the supply of milk during three days after weaning and the supply of an optimized pre-starter diet can increase the energy intake of the piglets after weaning and reduce the number of weaned piglets with clinical signs of an infection with Streptococcus suis.
    Texture, energy density & learning : implications for food intake
    Hogenkamp, P.S. - \ 2012
    Wageningen University. Promotor(en): Kees de Graaf, co-promotor(en): A. Stafleu; Monica Mars. - S.l. : s.n. - ISBN 9789461731227 - 143
    voedselopname - verzadigdheid - energieopname - textuur - viscositeit - geur en smaak - leren - food intake - satiety - energy intake - texture - viscosity - flavour - learning

    Food texture has been shown to be an important factor in the regulation of food (energy) intake. Liquid foods e.g. elicit weaker satiety responses than solid foods with a similar energy content, and texture affects satiation, i.e. ad libitum food intake. Whether theeffect of food texture on food intake stays the same over repeated exposure requires further investigation.
    The aim of this thesis is to investigate the role of food texture in learned satiation. We assessed the effect of texture on changes in ad libitum intake and expected satiation after repeated consumption of foods with different energy density.
    We conducted a series of learning experiments with healthy young adults. Participants repeatedly consumed a low-energy-dense (LED) and a high-energy-dense (HED) yogurt, which were either low (n=24) or high (n=22) in viscosity in one study; and consumed with a straw (liquid yogurt, n=34) or with a spoon (liquid yogurt, n=36; semi-solid yogurt, n=35) in a second study.
    Next, we investigated changes in expected satiation and intake after repeated consumption of a LED soup (n=32) or a HED soup (n=32) with similar appearance; and of a liquid and a semi-solid custard with a similar energy density (n=53). Additionally, we assessed the effect of texture, flavour and means of consumption on expected satiation of iso-caloric dairy products in 3 single-meal experiments.
    Finally, we served a fixed amount of a LED or HED food - either liquid or semi-solid - at each meal on 3 consecutive days, and measured ad libitum buffet intake directly after consumption of these foods (n=27).

    Texture clearly affected satiation:ad libitum intake was up to 30% higher of liquid foods when compared with semi-solids foods in all experiments (p<0.0001). Participants expected semi-solid foods to be more satiating than iso-caloric liquid foods (p<0.01), irrespective of the product’s flavour or its means of consumption. The texture of a fixed amount of food did not affect subsequent intake of other foods.

    Participants were able to learn about the foods’ satiating capacity after repeated consumption. Ad libitum intake of a HED high-viscous yogurt decreased and was 10% lower compared with a LED high-viscous yogurt after repeated consumption, while intake of a LED and HED low-viscous yogurt did not differ (interaction effect: p=0.04). We also observed thatappetite sensations changed when participants repeatedly consumed a liquid and semi-solid custard with a similar energy density (p<0.05). In addition, participants increased their intake from the ad libitum buffet after repeated consumption of a LED food (from 1745 ± 577 to 1979 ± 567 kcal), while their intake did not change after a HED food (interaction effect: p=0.02). This increase was observed irrespective of the texture of the test foods.
    Ad libitum intake was higher of liquid foods when compared with semi-solid foods, also after learning about the energy content of a food over repeated exposure.
    Participants did not adjust their intake and expected satiation consistently. Intake did not change when participants consumed a LED and a HED yogurt with a straw or with a spoon. We also did not observe profound changes in the expected satiation of a LED and HED soup or a liquid and semi-solid custard.
    Healthy young adults learned about the foods’ satiating capacity after repeated consumption. Changes in intake and expectations in response to learning did not depend on food texture.
    Food intake and expected satiation were not easily changed. The effect of food texture on satiation is important in the regulation of food intake, also after repeated exposure.

    Methane emissions from enteric fermentation in dairy cows, 1990-2008
    Bannink, A. - \ 2011
    Wageningen : Animal Sciences Group, Wageningen UR (WOt-werkdocument 265) - 63
    melkveehouderij - melkkoeien - methaan - emissie - excretie - registratie - broeikasgassen - energieopname - dairy farming - dairy cows - methane - emission - excretion - registration - greenhouse gases - energy intake
    The Dutch protocol for the national inventory estimates the methane emission of the average Dutch dairy cow based on a Tier 3 approach. A dynamic, mechanistic model is used to represent the enteric fermentation processes, using annual national statistics on feed intake and feed composition as model inputs. Dutch dairy rations are based mainly on roughage (3/4 of dry matter ingested) with a high proportion of grass products (2/3 of roughage dry matter). Between 1990 and 2008, there were continuous increases in dry matter intake, milk production and enteric methane emission. Methane emission ranged from 111 to 129 kg/cow/year, and from 17.6 to 15.4 g/kg fat- and protein-corrected milk. The present study indicates that uncertainties in the feed intake level and the proportion and composition of grass products contribute to the variation in predicted methane emission. In addition, internal model equations also greatly contribute to the uncertainty (representation of rumen acidity and yield of volatile fatty acids). The greatest part of the uncertainty in the methane emission factor (kg methane/cow/year) is determined by the uncertainty in the feed intake and stoichiometry of volatile fatty acid production, while the greatest part of the uncertainty in the methane conversion factor (methane energy as % of gross energy intake) is determined by the stoichiometry of volatile fatty acid production in combination with the acidity of rumen digesta. Although the applicability of national statistics as model inputs can be investigated relatively easily in follow-up studies, physiological research with dairy cattle will be required to fully validate the current internal model equations.
    Invloed van kunstmelk en voersamenstelling na spenen op energieopname en Streptococcus suis infecties bij biggen = Effect of milk intake and feed composition after weaning on energy intake and Streptococcus suis infection in piglets
    Peet-Schwering, C.M.C. van der; Dirx-Kuijken, N.C.P.M.M. ; Binnendijk, G.P. ; Raymakers, R. - \ 2011
    Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 529) - 34
    varkenshouderij - biggen - biggenvoeding - kunstmelk - speenleeftijd - energieopname - streptococcus suis - spenen - voedertoevoegingen - voersamenstelling - pig farming - piglets - piglet feeding - filled milk - age at weaning - energy intake - streptococcus suis - weaning - feed additives - feed formulation
    At Swine Innovation Centre Sterksel it was investigated whether the supply of milk during six days after weaning and the supply of an optimized pre-starter diet can increase the energy intake of the piglets after weaning and reduce the number of weaned piglets with clinical signs of an infection with Streptococcus suis. The results are described in this report.
    Verhogen van de energieopname direct na spenen als aanpak van streptococcen problemen
    Animal Sciences Group (ASG), - \ 2011
    Livestock Research
    varkenshouderij - spenen - kunstmelk - diergezondheid - biggen - energieopname - streptococcus - pig farming - weaning - filled milk - animal health - piglets - energy intake - streptococcus
    VIC Sterksel onderzoekt de mogelijkheden om via het verstrekken van kunstmelk de energieopname te verhogen. Doel: door middel van melk verstrekken het spenen vloeiend laten verlopen, zonder een speendip, met als resultaat gezonde biggen.
    Hongerige veren
    Emous, R.A. van; Veldkamp, T. - \ 2009
    De Pluimveehouderij 39 (2009)2. - ISSN 0166-8250 - p. 36 - 37.
    moederdieren - ouderdom - verenkleed - ruien - energie - energieopname - pluimveevoeding - dierenwelzijn - dams (mothers) - old age - plumage - moulting - energy - energy intake - poultry feeding - animal welfare
    Omdat moederdieren op oudere leeftijd al snel kaal worden hebben ze veel meer energie nodig voor onderhoud. Dit heeft gevolgen voor het voeren, blijkt uit een (Animal Sciences Group) ASG-studie
    Anamnesemethode: snel en doelmatig? : geautomatiseerde voedingsanamnese voor het vaststellen van energie-inname
    Hiemstra, G.K. ; Roos, N.M. de; Vries, J.H.M. de; Leibrandt, A. ; Rasmussen, E. ; Remijnse, T.A. ; Staveren, W.A. van - \ 2005
    Nederlands Tijdschrift voor Dietisten 60 (2005)4. - ISSN 0166-7203 - p. 88 - 96.
    voedselconsumptie - energieopname - voedselopname - dieetadvisering - vragenlijsten - eetpatronen - diëtisten - patiënten - food consumption - energy intake - food intake - diet counseling - questionnaires - eating patterns - dietitians - patients
    Doel van dit onderzoek was: meten van de reproduceerbaarheid van een bestaande voedselfrequentievragenlijst (VVL) bij een groep patiënten met ongewijzigd dieetadvies; meten van verandering in energie-inname bij een groep patiënten met gewijzigde dieetadvies; en evalueren van de bruikbaarheid van VVL bij patiënt en diëtist
    Zomereenden met wintergroei
    Krimpen, M.M. van; Buisonjé, F.E. de; Hoekman, J.J. - \ 2004
    De Pluimveehouderij 34 (2004)8. - ISSN 0166-8250 - p. 10 - 11.
    eendenvoeding - eenden - voersamenstelling - voederconversie - aminozuren - groei - omgevingstemperatuur - energieopname - slachtdieren - karkaskwaliteit - duck feeding - ducks - feed formulation - feed conversion - amino acids - growth - environmental temperature - energy intake - meat animals - carcass quality
    In de zomerperiode, bij hoge omgevingstemperaturen, blijft de energieopname en de groei van vleeseenden achter. Is dat met meer energie en meer aminozuren in het voer te verbeteren, zonder dat de slachtkwaliteit verslechtert? Het Praktijkonderzoek van de Animal Sciences Group van Wageningen UR in Lelystad heeft dit onderzocht
    Energie- en eiwitbehoefte van biologisch gehouden vleesvarkens
    Krimpen, M.M. van; Peet-Schwering, C.M.C. van der - \ 2004
    onbekend : Praktijkonderzoek Veehouderij (PV) (PraktijkRapport / Animal Sciences Group : Varkens ) - 20
    biologische landbouw - varkenshouderij - energieopname - varkensstallen - energiebehoeften - voederconversievermogen - organic farming - pig farming - energy intake - pig housing - energy requirements - feed conversion efficiency
    In this literature review, the differences in energy and protein requirement between organic and conventional growing finishing pigs were studied. In general, the environmental temperature in organic pig facilities is lower than in conventional ones. By way of compensation, organic pigs have higher energy requirements. On average, organic pigs have a higher feed intake and a unfavourable feed conversion ratio.
    De acute daling van leptine na een energiearme voeding : een biologische indicator voor de gevoeligheid voor het ontwikkelen van overgewicht?
    Mars, M. - \ 2004
    Wageningen University. Promotor(en): Frans Kok, co-promotor(en): Kees de Graaf; Lisette de Groot. - [S.I.] : S.n. - ISBN 9789085040521
    obesitas - overgewicht - voeding - hormonen - voedselopname - eetlustcontrole - voedselbeperking - dieet - energieopname - obesity - overweight - nutrition - hormones - food intake - appetite control - food restriction - diet - energy intake
    The last decades the prevalence of obesity has been increasing. However, large inter-individual differences in weight gain are observed. Poor energy intake regulation is one of the possible mechanisms behind a large susceptibility to weight gain. The hormone leptin is suggested to have a key-role in the regulation and restoration of energy balance. Therefore, we hypothesized that the acute leptin decline after energy restriction might be a marker for the susceptibility to weight gain. In other words, is the leptin response an individual trait that is related to the ability to restore energy balance and is it therefore related to the susceptibility to weight gain? To test this hypothesis we conducted three controlled intervention studies in which male subjects received an energy restriction of ~65% during a few days. First of all, we performed a reliability study in we which assessed the reliability of the insulin and ghrelin response on short-term (3 weeks) and long-term (1½ year). On the short-term, the leptin decline had a relatively high reliability (Intra Class Correlation [95%-Confidence interval]=0.66 [0.33; 0.85]) compared to the decline in insulin (ICC=0.45 [0.03; 0.74]) and the increase in ghrelin (ICC=0.34 [0; 0.67]). On the long-term however, the acute leptin response showed a lower reliability (ICC=0.34 [0; 0.67]). After that, we hypothesized that the leptin responsiveness to energy restriction is affected by the functionality of the leptin receptor; therefore we explored the effect of three common polymorphisms in the leptin receptor gene (Lys109Arg, Gln223Arg and Lys656Asn) on the acute leptin decline. The analyses revealed no statistically significant differences in leptin response between genotypes, i.e. between carriers and non-carriers of the mutant allele. Next, we investigated whether the acute decline in leptin is a biomarker for weight gain with different (intermediate) endpoints, i.e. appetite, energy intake compensation, and retrospective weight gain. We hypothesised that the decline in leptin is related to subjective appetite ratings, ratings that reflect hunger, fullness, desire to eat, prospective consumption, and total appetite. We observed that the magnitude of the acute decline was indeed positively associated with the increase in hunger (r=0.42; p<0.05), desire to eat (r=0.39; p<0.05), and total appetite (r=0.35; p<0.05). Next, we investigated the association between the amount of energy that is compensated in the days following energy restriction and the magnitude of the leptin decline during energy restriction. Although we found that leptin levels declined by 24% [95%-Confidence Interval: -33%; -15.9%] and subjects showed compensatory behaviour (143 ± 27% on the first day and 124 ± 20% on the second day after energy restriction), no association was observed between the magnitude of the leptin decline and energy intake compensation (r=0.22; ns). Lastly, we investigated whether individuals with stable weight show larger leptin declines to energy restriction than individuals who gained weight. Proportionally, an 8% smaller decrease in leptin was observed in men with retrospective weight gain. However, in a selected subgroup with a larger difference in retrospective weight gain, this difference in leptin response was not found; therefore, we concluded that the data did not provide convincing evidence for our hypothesis that men who gained weight are less leptin responsive to changes in energy balance than men who were weight stable.Overall, we conclude that the leptin decline to energy restriction is not a good biomarker for the susceptibility to weight gain. However, it may be a good indicator for energy balance or the increase in appetite during energy restriction.
    Body composition and diet of Chinese, Malays and Indians in Sininfluence on cardiovascular risk factorsgapore: and their
    Deurenberg-Yap, M. - \ 2000
    Agricultural University. Promotor(en): W.A. van Staveren; J.G.A.J. Hautvast. - S.l. : S.n. - ISBN 9789058082923 - 170
    lichaamssamenstelling - lichaamsvet - obesitas - voedselopname - calorieënopname - energieopname - voedingsvet - cholesterol - verzadigde vetten - onverzadigde vetten - vruchten - groenten - voedselgranen (hele korrel) - etnische groepen - cardiovasculair systeem - risicofactoren - singapore - body composition - body fat - obesity - food intake - caloric intake - energy intake - dietary fat - cholesterol - saturated fats - unsaturated fats - fruits - vegetables - whole grains - ethnic groups - cardiovascular system - risk factors - singapore

    This thesis describes the studies on body composition and dietary intakes of the three major ethnic groups residing in Singapore, and how these are related to cardiovascular risk factors in these groups.

    Body composition : Body fat percentage was measured using a four-compartment model described by Baumgartner. When the relationship between body mass index (BMI) and body fat percentage was studied, it was discovered that Singaporeans have higher percentage of body fat compared to Caucasians with the same BMI and that the BMI cut-off value for obesity in Chinese and Malays is around 27 kg/m 2 , while that for Indians is around 26 kg/m 2 . At levels of BMI and waist-to-hip ratio which are much lower than the WHO recommended cut-off limits for obesity and abdominal fatness respectively, both the absolute and relative risks of developing cardiovascular risk factors are markedly elevated for all three ethnic groups. Both the excessive fat accumulation and increased risks at low levels of BMI signal a need to re-examine cut-off values for obesity among Chinese, Malays and Indians.

    Diet : Dietary intakes of energy, total fat, saturated fat, polyunsaturated fat, monounsaturated fat and cholesterol were measured using a food frequency questionnaire specially validated for this purpose. In addition, intakes of fruits, vegetables and grain-based foods were also measured using the same questionnaire. Singaporeans generally have a low intake of fruits, vegetables and whole grain products. The intake of total fat is just within the upper recommended limit while that for saturated fat is higher than the recommended level. On a group level, it is found that high intakes of fat, saturated fat and low intakes of polyunsaturated fat and vegetables affect serum cholesterol levels adversely. However, on an individual level, due to the rather homogenous intake patterns among the three groups, this cross sectional study was unable to demonstrate that dietary intakes could explain the differences in serum cholesterol levels among ethnic groups.

    In summary, the thesis shows that in the light of increased body fat percentage and cardiovascular risks at low BMI, there is a need to re-examine the WHO's cut-off values for the three major ethnic groups in Singapore. Longitudinal studies are also needed for better insight into the effect of dietary intakes and other lifestyle risk factors on cardiovascular risk factors and mortality.

    Invloed van voeding van biggen en vleesvarkens op groei en karkaskwaliteit
    Huiskes, J.H. - \ 1989
    Rosmalen : Proefstation voor de Varkenshouderij (Proefverslag / Proefstation voor de Varkenshouderij P1.34) - 78
    diervoedering - varkensvoeding - biggen - slachtdieren - groei - vervetting - voersamenstelling - energieopname - afmesten - karkaskwaliteit - onderzoek - animal feeding - pig feeding - piglets - meat animals - growth - fatty degeneration - feed formulation - energy intake - finishing - carcass quality - research
    Het hier beschreven onderzoek is opgezet om inzicht te verkrijgen in de invloed van de voeding van biggen en vleesvarkens op groei en karkas-kwaliteit. Hierbij gold als kernvraag de relatie tussen de opname aan energiewaarde (EW) per dag en de vetbedekking van de borstholte en vetaanwas in de buik
    Patterns of nitrogen and energy intake and their relation to the control of voluntary feed consumption in ruminants and monogastric animals
    Ketelaars, J.J.M.H. - \ 1984
    Wageningen : Centre for Agrobiological Research - 176
    herkauwers - voeropname - voedingsfysiologie - spijsvertering - energieopname - eiwitinname - verteerbaarheid - spijsverteringsstelsel - systeemanalyse - modellen - voedersystemen - ruminants - feed intake - nutrition physiology - digestion - energy intake - protein intake - digestibility - digestive system - systems analysis - models - feeding systems
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