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

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    Programming effects of glucose, fructose or galactose in post-weaning diet on adiposity and serum adipokines in adult mice
    Bouwman, L.M.S. ; Fernández Calleja, J.M.S. ; Keijer, J. ; Oosting, A. ; Schothorst, E.M. van - \ 2016
    programming effects - glucose - fructose - post-weaning diet - adiposity - serum adipokines
    Replacing lactose from calf milk replacers : effects on digestion and post-absorptive metabolism
    Gilbert, M.S. - \ 2015
    Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Walter Gerrits; Henk Schols. - Wageningen : Wageningen University - ISBN 9789462576032 - 171
    vleeskalveren - lactose - kunstmelk - polysacchariden - glucose - fructose - glycerol - zetmeelvertering - metabolisme - fermentatie - kalvervoeding - diervoeding - voedingsfysiologie - veal calves - lactose - filled milk - polysaccharides - glucose - fructose - glycerol - starch digestion - metabolism - fermentation - calf feeding - animal nutrition - nutrition physiology

    Summary PhD thesis Myrthe S. Gilbert

    Replacing lactose from calf milk replacers – Effects on digestion and post-absorptive metabolism

    Veal calves are fed milk replacer (MR) and solid feed. The largest part of the energy provided to veal calves originates from the MR. Calf MR contains 40 to 50% lactose, originating from whey, a by-product from cheese production. High and strongly fluctuating dairy prices are a major economic incentive to replace lactose from the calf MR by alternative energy sources. The objective of this thesis was to study the effects of replacing lactose from calf MR on nutrient digestion and fermentation and post-absorptive metabolism.

    In Chapter 2 and 3, four starch products (SP) were evaluated for replacing lactose. The four SP differed in size and branching, and consequently required different ratios of starch-degrading enzymes for their complete hydrolysis to glucose. Gelatinized starch required α-amylase and (iso)maltase; maltodextrin required (iso)maltase and α-amylase; maltodextrin with α-1,6-branching required isomaltase, maltase and α-amylase and maltose required maltase. In Chapter 2, adaptation to these SP was assessed during 14 weeks, using a within-animal titration study. Forty male Holstein-Friesian calves (n = 8 per treatment) were assigned to either a lactose control MR or one of four titration strategies, each testing the stepwise exchange of lactose for one of the SP. For control calves, fecal dry matter (DM) content and fecal pH did not change over time. The response in fecal DM content and fecal pH in time did not differ between SP treatments and decreased linearly with 0.57% and 0.32 per week, respectively, where one week corresponded to an increase in SP inclusion of 3%. This indicates that the capacity for starch digestion was already exceeded at low inclusion levels, resulting in SP fermentation. All SP required maltase to achieve complete hydrolysis to glucose and it was, therefore, suggested that maltase is the rate-limiting enzyme in starch digestion in milk-fed calves.

    Following the titration, a fixed inclusion level of 18% of the SP in the MR was applied. Effects on starch-degrading enzyme activity, nutrient disappearance, SP fermentation and jugular glucose appearance were measured (Chapter 3). Lactase activity in the brush border was high in the proximal small intestine of all calves, resulting in a high apparent ileal disappearance of lactose (≥ 99% of intake). Maltase and isomaltase activities in the brush border were not increased for any of the SP treatments. Luminal α-amylase activity was lower in the proximal small intestine but greater in the distal small intestine of SP-fed calves compared to control calves. This amylase activity in the distal small intestine of SP-fed calves might have been of microbial origin. Apparent SP disappearance did not differ between SP treatments. The difference between apparent ileal (62%) and total tract (99%) SP disappearance indicated substantial SP fermentation in the large intestine (37% of intake). In addition, total tract SP fermentation was quantified using fecal 13C excretion which originated from the naturally 13C-enriched corn SP. Total tract SP fermentation averaged 89% of intake, regardless of SP treatment. MR leaking into the reticulorumen was measured as the recovery of Cr in the reticulorumen at slaughter after feeding MR pulse-dosed with Cr 4h prior to slaughter. MR leaking into the reticulorumen averaged 11% for SP-fed calves. By difference, this leaves 41% of the SP intake fermented in the small intestine. This coincided with increased fecal nitrogen (N) and DM losses for SP-fed calves. However, apparent total tract crude fat disappearance tended to increase when replacing lactose with SP. The substantial SP fermentation indicates that only 10% of the SP intake was enzymatically hydrolyzed and absorbed as glucose. This was in agreement with the marginal increase in 13C enrichment in peripheral plasma glucose after feeding naturally 13C-enriched gelatinized starch and maltose, compared to a clear increase after feeding naturally 13C-enriched lactose to control calves. It was concluded that fermentation, rather than enzymatic digestion, is the main reason for small intestinal starch disappearance in milk-fed calves. The expected decrease in growth performance with such extensive SP fermentation is partially compensated by the greater crude fat digestion and possibly by a reduced urinary glucose excretion when replacing lactose with SP.

    Glucose, fructose and glycerol do not require enzymatic hydrolysis and can be absorbed directly from the small intestine. However, these lactose replacers might differentially affect glucose and insulin metabolism and with that energy partitioning. The effects of partly replacing lactose with glucose, fructose or glycerol on energy and N partitioning and glucose homeostasis and insulin sensitivity were, therefore, studied in Chapter 4 and 5. Forty male Holstein-Friesian calves either received a lactose control MR or a MR in which one third of the lactose was replaced with glucose, fructose or glycerol (n = 10 per treatment). Energy and N retention were not affected by MR composition. Fructose absorption from the small intestine was incomplete resulting in fructose fermentation. This resulted in fecal losses of DM, energy and N and the lowest numerical energy and N retention for fructose-fed calves. Postprandial plasma concentrations of glucose exceeded the renal threshold for glucose in glucose-fed calves and control calves, which resulted in urinary glucose excretion. Glycerol was likely excreted with the urine of glycerol-fed calves. Oxidation of glucose, fructose and glycerol was quantified by feeding a single dose of [U-13C]glucose, [U-13C]fructose or [U-13C]glycerol with the MR and subsequently measuring 13CO2 production. Oxidation of lactose replacers did not differ between lactose replacers and averaged 72% of intake. However, the time at which the maximum rate of oxidation was reached was delayed for fructose-fed compared to glucose-fed and glycerol-fed calves, indicating that fructose was converted into other substrates before being oxidized. Conversion of fructose and glycerol into glucose was confirmed by an increase in 13C enrichment of peripheral plasma glucose after feeding [U-13C]fructose and [U-13C]glycerol, respectively. Insulin sensitivity did not differ between MR treatments, but was already low at the start of the experiment at 15 weeks of age and remained low throughout the experiment. It was concluded that glucose and glycerol can replace one third of the lactose from the calf MR, but that inclusion of fructose should be lower to prevent incomplete absorption from the small intestine.

    In literature and the studies in this thesis, high inter-individual variation in growth performance was found in veal calves. The experiment described in Chapter 6 was, therefore, designed to assess the predictability of later life growth performance by charactering calves in early life. In addition, it was examined whether the ability of calves to cope with MR in which lactose is partially replaced by alternative energy sources can be predicted. From 2 to 11 weeks of age, male Holstein-Friesian calves were fed a lactose control MR and solid feed according to a practical feeding scheme and were characterized individually using targeted challenges related to feeding motivation, digestion, post-absorptive metabolism, immunology, behavior and stress. Based on the results in Chapter 4, a combination of glucose, fructose and glycerol in a 2:1:2 ratio was used to replace half of the lactose from the MR (GFG). From 11 to 27 weeks of age, calves received a lactose control MR or the GFG MR (n = 65 per treatment). Growth performance from 11 to 27 weeks of age tended to be lower for GFG-fed than for control calves (-25 g/d). Measurements in early life explained 12% of the variation in growth performance in later life. However, this was mainly related to variation in solid feed refusals. When growth performance was adjusted to equal solid feed intake, only 4% of the variation in standardized growth performance in later life, reflecting feed efficiency, could be explained by early life measurements. This indicates that > 95% of the variation in feed efficiency in later life could not be explained by early life characterization. It is hypothesized that variation in health status explains substantial variation in feed efficiency in veal calves. Significant relations between fasting plasma glucose concentrations, fecal dry matter and fecal pH in early life and feed efficiency in later life depended on MR composition. These measurements are, therefore, potential tools for screening calves in early life on their ability to cope with a MR in which half of the lactose is replaced by glucose, fructose and glycerol (in a 2:1:2 ratio).

    The studies reported in this thesis demonstrate that glycerol, glucose and a combination of glucose, fructose and glycerol in a 2:1:2 ratio are promising lactose replacers. The effects of replacing lactose by other carbohydrate or energy sources described in this thesis are required to evaluate the potential of lactose replacers for inclusion in calf milk replacers and provide input for feed evaluation for calves and ruminants.

    Differential effects of proteins and carbohydrates on postprandial blood pressure-related responses
    Teunissen-Beekman, K.F.M. ; Dopheide, J. ; Geleijnse, J.M. ; Bakker, S.J.L. ; Brink, E.J. ; Leeuw, P.W. de; Serroyen, J. ; Baak, M.A. van - \ 2014
    The British journal of nutrition 112 (2014)4. - ISSN 0007-1145 - p. 600 - 608.
    randomized controlled-trials - plasma amino-acids - healthy-subjects - insulin responses - dietary-protein - overweight adults - energy-intake - whey-protein - glucose - fructose
    Diet composition may affect blood pressure (BP), but the mechanisms are unclear. The aim of the present study was to compare postprandial BP-related responses to the ingestion of pea protein, milk protein and egg-white protein. In addition, postprandial BP-related responses to the ingestion of maltodextrin were compared with those to the ingestion of sucrose and a protein mix. We hypothesised that lower postprandial total peripheral resistance (TPR) and BP levels would be accompanied by higher plasma concentrations of nitric oxide, insulin, glucagon-like peptide 1 (GLP-1) and glucagon. On separate occasions, six meals were tested in a randomised order in forty-eight overweight or obese adults with untreated elevated BP. Postprandial responses of TPR, BP and plasma concentrations of insulin, glucagon, GLP-1 and nitrite, nitroso compounds (RXNO) and S-nitrosothiols (NOx) were measured for 4 h. No differences were observed in TPR responses. Postprandial BP levels were higher after the ingestion of the egg-white-protein meal than after that of meals containing the other two proteins (P
    Factors contributing to the variation in feline urinary oxalate excretion
    Dijcker, J.C. ; Hagen-Plantinga, E.A. ; Everts, H. ; Queau, Y. ; Biourge, V.C. ; Hendriks, W.H. - \ 2014
    Journal of Animal Science 92 (2014)3. - ISSN 0021-8812 - p. 1029 - 1036.
    glycolate excretion - dietary-protein - ascorbic-acid - calcium - cats - hydroxyproline - vitamin-b-6 - fructose - requirement - absorption
    This study aimed to identify factors (season, animal, and diet) contributing to the variation in urinary oxalate (Uox) excretion rate, Uox concentration, and urine volume in healthy adult cats. A data set (1,940 observations) containing information on Uox excretion rate of 65 cats fed 252 diets (i.e., each diet was fed to a group of 6 to 8 cats), with known dietary oxalate concentrations, collected over a 6 yr period at a feline nutrition facility, were retrospectively analyzed. Data related to season, animal (i.e., age, gender, body weight, and breed), and diet (i.e., nutrient content) characteristics were subjected to stepwise multivariate regression analysis to identify factors significantly correlated to Uox excretion rate (µmol/(kg BW0.67·d)) and concentration (mmol/L) as well as urine volume (mL/(kg BW0.67·d)). Independent factors significantly (P <0.05) associated with lower Uox concentration (mmol/L) included greater ash, Ca, and Na intake and lower nitrogen-free extract, total dietary fiber, P, and oxalate intake, and a body weight
    Stable isotape ratios of H, C, N an O in Italian citrus juices
    Bontempo, L. ; Caruso, R. ; Fiorillo, M. ; Gambino, G.L. ; Perini, M. ; Simoni, M. ; Traulo, P. ; Wehrens, H.R.M.J. ; Gagliano, G. ; Camin, F. - \ 2014
    Journal of Mass Spectrometry 49 (2014)9. - ISSN 1076-5174 - p. 785 - 791.
    fruit juices - mass-spectrometry - orange juice - sugar addition - snif-nmr - water - ethanol - irms - fructose - origin
    Stable isotope ratios (SIRs) of C, N, H and O have been exensively used in fruit juices quality control (ENV and AOAC methods) to detect added sugar and the watering down of concentrated juice, practices prohibited by European legislation (EU Directive 2012/12). The European Fruit Juice Association (AIJN) set some reference guidelines in order to allow the judging of the genuiness of a juice. Moreover, various studies have been carried out to determine the natural variability of SIRs in fruit juices, but none of these has investigated SIRs extensively in authentic citrus juices from Italy. In this work, about 500 citrus juice samples were officially collected in Italy by the Italian Ministry of Agricultural and Forestry Policies from 1998 onwards. (D/H)I and (D/H)II in ethanol and d13Cethanol, d13Cpulp, d13Csugars, d18Ovegetalwater, d15Npulp, and d18Opulp were determined using Site-Specific Natural Isotope Fractionation-Nuclear Magnetic Resonance and Isotope Ratio Mass Spectrometry, respectively. The characteristic ranges of variability in SIRs in genuine Italian citrus juice samples are here presented as well as their relationships and compliance with the limits indicated by the AIJN and others proposed in the literature. In particular, the Italian range of values was found to be not completely in agreement with AIJN guidelines, with the risk that genuine juices could be judged as not genuine. Variety seems not to influence SIRs, whereas harvest year and region of origin have some influence on the different ratios, although their data distribution shows overlapping when principal component analysis is applied.
    Greenhouse climate control affects postharvest tomato quality
    Farneti, B. ; Schouten, R.E. ; Qian, T. ; Dieleman, J.A. ; Tijskens, L.M.M. ; Woltering, E.J. - \ 2013
    Postharvest Biology and Technology 86 (2013). - ISSN 0925-5214 - p. 354 - 361.
    nutritional quality - closed greenhouse - apple fruit - temperature - yield - radiation - sweetness - cultivar - fructose - behavior
    In this study, important quality properties such as firmness, sugar and acid levels were measured and analysed in tomatoes harvested from three greenhouses during a five month period and stored at 16 degrees C for over 20 days. Tomatoes were harvested from three identical, neighbouring, greenhouses which were either conventionally ventilated (open greenhouse) or mechanically cooled (semi-closed greenhouses). Sugar and acids levels were hardly affected by greenhouse type. Compared to the open greenhouse, semi-closed greenhouses produced heavier and less mature (firmer) fruit at the commercial harvesting stage based on colour. Fruit maturity differences could be linked to the vertical temperature gradient and to CO2 levels in the different greenhouses. This indicates that CO2 levels and temperature affect the synchronisation between colour and firmness maturity at harvest. The acceptance period, i.e., the time period both tomato colour and firmness are considered acceptable by consumers, will likely be positively affected when growers switch from conventionally ventilated to semi-closed production systems. Additional to greenhouse effects also effects of the harvest month were observed. The sugar to acid ratio was highest and glucose to fructose ratio was lowest in July, the month with the highest irradiance, irrespective of greenhouse type. The estimated value for the maximum firmness (F-max) varied from 17.9 N in August to 31.2 N in June. This monthly variation in F-max explains an important part of the variation found in the postharvest behaviour of tomatoes. Interestingly, the monthly variation in F-max showed the same trend as found for the monthly initial sugar levels. It might be hypothesised that the monthly variation in glucose and fructose levels causes variation in that part of firmness that is generated by cell turgor. The monthly variation in F-max, sugar and acid levels could not be linked to climate conditions and remains to be elucidated. (C) 2013 Elsevier B.V. All rights reserved.
    Use of Furandicarboxylic Acid and Its Decyl Ester as Additives in the Fischers's Glycosylation of Decanol by D-Glucose: Physiochemical Properties of the Surfactant Compositions Obtained
    Es, D.S. van; Oduber, X. ; Estrine, B. ; Marinkovic, S. - \ 2013
    Journal of Surfactants and Detergents 16 (2013)2. - ISSN 1097-3958 - p. 147 - 154.
    direct conversion - one-pot - pentosides - oxidation - chemicals - fructose
    2,5-Furandicarboxylic acid is a promising bio-based platform chemical that may serve as a ‘green’ substitute for terephthalate in polyesters. In the present work, straightforward glycosylation of decanol with unprotected and non-activated d-glucose was performed under reduced quantities of sulfuric acid as catalyst (down to 0.9 mol%) in the presence of 2,5-furandicarboxylic acid or its n-decyl ester as additive. Yield of decyl monoglucosides was highly improved by the use of the additives. Moreover, the presence of additive also limited the colouration of the reaction. The physical and chemical properties of the surfactant composition produced were studied and compared to reference compositions. The ultimate biodegradability of furan-2,5-dicarboxylic acid (FDCA) and its n-decyl ester formed or produced in the bulk reaction medium was also studied in order to assess its potential use in surfactant industry.
    Molecular characterization of the glucose isomerase from the thermophilic bacterium Fervidobacterium gondwanense
    Kluskens, L.D. ; Zeilstra, J.B. ; Geerling, A.C.M. ; Vos, W.M. de; Oost, J. van der - \ 2010
    Environmental Technology 31 (2010)10. - ISSN 0959-3330 - p. 1083 - 1090.
    d-xylose isomerase - biochemical-characterization - thermotoga-neapolitana - thermus-thermophilus - escherichia-coli - thermostability - cloning - purification - expression - fructose
    The gene coding for xylose isomerase from the thermophilic bacterium Fervidobacterium gondwanense was cloned and overexpressed in Escherichia coli. The produced xylose isomerase (XylA), which closely resembles counterparts from Thermotoga maritima and T. neapolitana, was purified and characterized. It is optimally active at 70 degrees C, pH 7.3, with a specific activity of 15.0 U/mg for the interconversion of glucose to fructose. When compared with T. maritima XylA at 85 degrees C, a higher catalytic efficiency was observed. Divalent metal ions Co2+ and Mg2+ were found to enhance the thermostability
    Kinetics of the glucose/glycine Maillard reaction pathways: influences of pH and reactant initial concentrations
    Martins, S.I.F.S. ; Boekel, M.A.J.S. van - \ 2005
    Food Chemistry 92 (2005)3. - ISSN 0308-8146 - p. 437 - 448.
    n-(1-deoxy-d-fructos-1-yl)-glycine degradation pathways - casein systems - amino-acids - model - caramelization - phosphate - products - fructose - glucose - ions
    A previously proposed kinetic model for the glucose/glycine Maillard reaction pathways has been validated by changing the initial pH (4.8, 5.5, 6.0, 6.8 and 7.5) of the reaction and reactant initial concentrations (1:2 and 2:1 molar ratios were compared to the 1:1 ratio). The model consists of 10 steps, each characterised by a rate constant. The initial pH had a different effect on the various rate constants, and the results suggest a mixture between specific acid and base catalysis. pH¿rate profiles were established and, from these, a quantitative relationship was derived: kobs = ke(10pD × pH), in which kobs is the estimated rate constants from experiments, ke an expression for the elementary reaction, and pD the parameter describing the pH-dependence. The parameters ke and pD were estimated from the pH-rate profiles. This equation thus expresses the pH-dependence of rate constants in much the same way as the Arrhenius equation does for the temperature-dependence of rate constants. The initial concentrations of glucose and glycine did not have an effect on the estimated rate constants, indicating that the model is robust to change in initial concentrations of the reactants. Finally, a sensitivity analysis of the model was performed to highlight the important steps, as well as finding possible redundant ones. Again, the model performed well; all steps were important and the model was consistent with the established reaction mechanism.
    Melanoidins extinction coefficient in the glucose/glycine Maillard reaction
    Martins, S.I.F.S. ; Boekel, M.A.J.S. van - \ 2003
    Food Chemistry 83 (2003). - ISSN 0308-8146 - p. 135 - 142.
    amino-acid - d-glucose - glycine - polymers - fructose - products - model - sugar
    Melanoidins (brown, nitrogenous polymers and co-polymers) are the final products of the Maillard reaction. The glucose/glycine melanoidins extinction coefficient was determined using C-14-labelled glucose at three different reaction conditions. The absorbance was measured at different wavelengths (420, 450, 470 and 490 nm) and the extinction coefficient determined for each. The value of the extinction coefficient can be used to recalculate browning, measured as absorbance units, into melanoidins concentration in terms of sugar molecules incorporated. The amount of C-14-labelled sugar molecules was estimated in melanoidins separated via dialysis with a cut-off value of 3500 Da. These melanoidins only represented approximate to12% of the total colour formed. The extinction coefficient of the melanoidins remained constant during the observation period. At 470 nm, values of 0.65 (+/-0.02) 1 mmol(-1) cm(-1); 0.66 (+/-0.02) 1 mmol(-1) cm(-1) and 0.62 (+/-0.05) 1 mmol(-1) cm(-1), were obtained at 120 degreesC pH 6.8, 100 degreesC pH 6.8 and 100 degreesC pH 5.5, respectively. The difference is not significant. The extinction coefficient appeared to not to vary within the pH and temperature range studied. From the elemental analysis, the nondialysable melanoidins elementary composition seemed to be influenced by the reaction conditions, which was supposed to be related to the presence of side-chains on the melanoidin backbone. A trend was observed in the melanoidins C/N ratio: it decreased with increasing reaction pH as well as it changed to a lower level, of about 8, as the extent of browning increased. (C) 2003 Elsevier Ltd. All rights reserved.
    Fructo-oligosachariden geen geschikte groeibevorderaars
    Peet-Schwering, C. van der; Houdijk, J. ; Binnendijk, G. - \ 1999
    Praktijkonderzoek varkenshouderij 13 (1999)3. - ISSN 1382-0346 - p. 25 - 27.
    biggen - varkensvoeding - groei - toevoegingen - voedersupplementen - fructose - oligosacchariden - piglets - pig feeding - growth - additives - feed supplements - fructose - oligosaccharides
    Fructo-oligosachariden (FOS) zijn geen geschikt alternatief voor anti-microbiële groeibevorderaars in eiwitrijk speenvoer voor biggen. Biggen die FOS in eiwitrijk voer verstrekt krijgen nemen de eerste veertien dagen van de opfokperiode minder voer open groeien langzamer dan biggen die avilamycine in het voer verstrekt krijgen
    Metabole gevolgen van het gebruik van polyalcoholen en fructose-literatuurstudie. Deel 5, 6 en 7. Maltitol, lactitol en lycasin
    Wiel-Wetzels, W.A.M. van der - \ 1982
    Voeding 43 (1982). - ISSN 0042-7926 - p. 79 - 81.
    alcoholen - fructose - metabolisme - organische scheikunde - alcohols - metabolism - organic chemistry
    Over de fysische en chemische eigenschappen van genoemde zoetstoffen in relatie tot de stofwisseling
    Bepaling van het gehalte aan toegevoegd bindmiddel op basis van melasse
    Frijns, L.M.H. ; Muuse, B.G. - \ 1981
    Wageningen : RIKILT (Verslag / RIKILT 81.07) - 3
    melasse - glucose - fructose - sucrose - luzernebrokken - grasbrokken - korrelvoer - molasses - glucose - fructose - sucrose - lucerne pellets - grass pellets - pelleted feeds
    In 10 melasses en luzernemelen, grasmelen en mengsels van beide werd het gehalte bepaald aan glucose, fructose en saccharose. Ook werd nagegaan of in melasse het gehalte aan raffinose als kenmerk gebruikt zou kunnen worden. Tevens werd in de monsters melasse het vochtgehalte bepaald.
    Maisverwerking, verwijdering van kiem, bijprodukten
    Anonymous, - \ 1968
    Wageningen : [s.n.] (Literatuurlijst / Centrum voor landbouwpublikaties en landbouwdocumentatie no. 3042)
    bibliografieën - fructose - glucose - maïs - maïszetmeel - maltose - plantaardige vetten - plantaardige oliën - verwerking - zea mays - bibliographies - maize - maize starch - plant fats - plant oils - processing
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