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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    Effect of protein provision via milk replacer or solid feed on protein metabolism in veal calves
    Berends, H. ; Borne, J.J.G.C. van den; Røjen, B.A. ; Hendriks, W.H. ; Gerrits, W.J.J. - \ 2015
    Journal of Dairy Science 98 (2015)2. - ISSN 0022-0302 - p. 1119 - 1126.
    heavy preruminant calves - amino-acids - energy-metabolism - rumen development - dairy-cattle - nitrogen - urea - growth - performance - deposition
    The current study evaluated the effects of protein provision to calves fed a combination of solid feed (SF) and milk replacer (MR) at equal total N intake on urea recycling and N retention. Nitrogen balance traits and [15N2]urea kinetics were measured in 30 calves (23 wk of age, 180 ± 3.7 kg of body weight), after being exposed to the following experimental treatments for 11 wk: a low level of SF with a low N content (SF providing 12% of total N intake), a high level of SF with a low N content (SF providing 22% of total N intake), or a high level of SF with a high N content (SF providing 36% of total N intake). The SF mixture consisted of 50% concentrates, 25% corn silage, and 25% straw on a dry matter basis. Total N intake was equalized to 1.8 g of N·kg of BW-0.75·d-1 by adjusting N intake via MR. All calves were housed individually on metabolic cages to allow for quantification of a N balance of calves for 5 d, and for the assessment of urea recycling from [15N2]urea kinetics. Increasing low-N SF intake at equal total N intake resulted in a shift from urinary to fecal N excretion but did not affect protein retention (0.71 g of N·kg of BW-0.75·d-1). Increasing low-N SF intake increased urea recycling but urea reused for anabolism remained unaffected. Total-tract neutral detergent fiber digestibility decreased (-9%) with increasing low-N SF intake, indicating reduced rumen fermentation. Increasing the N content of SF at equal total N intake resulted in decreased urea production, excretion, and return to ornithine cycle, and increased protein retention by 17%. This increase was likely related to an effect of energy availability on protein retention due to an increase in total-tract neutral detergent fiber digestion (>10%) and due to an increased energy supply via the MR. In conclusion, increasing low-N SF intake at the expense of N intake from MR, did not affect protein retention efficiency in calves. Increasing the N content of SF at equal total N intake decreased urea production, increased protein retention, and coincided with improved fiber degradation. Therefore, results suggest that low N availability in the rumen limits microbial growth and rumen fermentation in calves fed low-N SF (93 g of CP/kg of DM), and this effect cannot be compensated for by recycling of urea originating from MR.
    Effect of olive mill wastewater phenol compounds on reactive carbonyl species and Maillard reaction end-products in ultrahigh-temperature-treated milk
    Troise, A.D. ; Fiore, A. ; Colantuono, A. ; Kokkinidou, S. ; Peterson, D.G. ; Fogliano, V. - \ 2014
    Journal of Agricultural and Food Chemistry 62 (2014)41. - ISSN 0021-8561 - p. 10092 - 10100.
    advanced glycation endproducts - nonfat dry milk - amino-acids - flavor components - mass-spectrometry - heat-treatment - model systems - bovine-milk - lc-ms - protein
    Thermal processing and Maillard reaction (MR) affect the nutritional and sensorial qualities of milk. In this paper an olive mill wastewater phenolic powder (OMW) was tested as a functional ingredient for inhibiting MR development in ultrahigh-temperature (UHT)-treated milk. OMW was added to milk at 0.1 and 0.05% w/v before UHT treatment, and the concentration of MR products was monitored to verify the effect of OMW phenols in controlling the MR. Results revealed that OMW is able to trap the reactive carbonyl species such as hydroxycarbonyls and dicarbonyls, which in turn led to the increase of Maillard-derived off-flavor development. The effect of OMW on the formation of Amadori products and N-e-(carboxymethyl)-lysine (CML) showed that oxidative cleavage, C2–C6 cyclization, and the consequent reactive carbonyl species formation were also inhibited by OMW. Data indicated that OMW is a functional ingredient able to control the MR and to improve the nutritional and sensorial attributes of milk
    Urea Recycling Contributes to Nitrogen Retention in Calves Fed Milk Replacer and Low-Protein Solid Feed
    Berends, H. ; Borne, J.J.G.C. van den; Røjen, B.A. ; Baal, J. van; Gerrits, W.J.J. - \ 2014
    The Journal of Nutrition 144 (2014)7. - ISSN 0022-3166 - p. 1043 - 1049.
    lactating holstein cows - drained visceral extraction - heavy preruminant calves - rumen development - veal calves - transporter-b - arterial urea - amino-acids - kinetics - infusion
    Urea recycling, with urea originating from catabolism of amino acids and hepatic detoxification of ammonia, is particularly relevant for ruminant animals, in which microbial protein contributes substantially to the metabolizable protein supply. However, the quantitative contribution of urea recycling to protein anabolism in calves during the transition from preruminants (milk-fed calves) to ruminants [solid feed (SF)–fed calves] is unknown. The aim of this study was to quantify urea recycling in milk-fed calves when provided with low-protein SF. Forty-eight calves [164 ± 1.6 kg body weight (BW)] were assigned to 1 of 4 SF levels [0, 9, 18, and 27 g of dry matter (DM) SF · kg BW-0.75 · d-1] provided in addition to an identical amount of milk replacer. Urea recycling was quantified after a 24-h intravenous infusion of [15N2]urea by analyzing urea isotopomers in 68-h fecal and urinary collections. Real-time qPCR was used to measure gene expression levels of bovine urea transporter B (bUTB) and aquaglyceroporin-3 and aquaglyceroporin-7 in rumen wall tissues. For every incremental gram of DM SF intake (g DM · kg0.75), nitrogen intake increased by 0.70 g, and nitrogen retention increased by 0.55 g (P <0.01). Of this increase in nitrogen retention, 19% could be directly explained by urea recycling. Additionally, part of the observed increase in nitrogen retention could be explained by the extra protein provided by the SF and likely by a greater efficiency of postabsorptive use of nitrogen for gain. Ruminal bUTB abundance increased (P <0.01) with SF provision. Aquaglyceroporin-3 expression increased (P <0.01) with SF intake, but aquaglyceroporin-7 expression did not. We conclude that in addition to the increase in digested nitrogen, urea recycling contributes to the observed increase in nitrogen retention with increasing SF intake in milk-fed calves. Furthermore, ruminal bUTB and aquaglyceroporin-3 expression are upregulated with SF intake, which might be associated with urea recycling.
    Protein source and dietary structure influence growth performance, gut morphology, and hindgut fermentation characteristics in broilers
    Qaisrani, S.N. ; Moquet, P.C.A. ; Krimpen, M.M. van; Kwakkel, R.P. ; Verstegen, M.W.A. ; Hendriks, W.H. - \ 2014
    Poultry Science 93 (2014)12. - ISSN 0032-5791 - p. 3053 - 3064.
    feed particle-size - nutrient digestibility - amino-acids - canola-meal - parameters - chickens - wheat - corn - pigs - starters
    An experiment with 210 male (Ross 308) 1-d-old broilers was conducted to test the hypothesis that a coarse diet improves performance of broilers fed a poorly digestible protein source. A highly digestible diet based on soybean meal was gradually replaced by a low digestible diet based on rapeseed meal (RSM) in 5 steps (RSM-0%, RSM-25%, RSM-50%, RSM-75%, and RSM-100%). Two diet structures (fine and coarse) were used as an additional factor. These 2 factors and their interactions were tested at different ages in a factorial arrangement with 10 dietary treatments. An increase in indigestible dietary protein negatively affected feed intake (P = 0.003), BW gain (P = 0.008), and feed conversion ratio (P = 0.034). This increase in dietary indigestible protein contents resulted in a decrease (P = 0.001) in total cecal volatile fatty acid concentration from 209.1 to 125.9 mmol/kg of DM digesta in broilers with increasing RSM in diets. Increase in the indigestible protein level, from RSM-0% to RSM-100%, resulted in a decrease (P = 0.042) in villus heights (1,782 vs. 1,574 µm), whereas crypt depths increased (P = 0.021; 237 vs. 274 µm). A coarse diet improved feed intake (P = 0.006), BW gain (P = 0.014), and feed conversion ratio (P = 0.009). Broilers fed coarse diets had approximately 11, 24, and 10% lower relative empty weights of the crop, proventriculus, and jejunum, respectively, whereas a 15% heavier gizzard was found compared with those fed the fine diets. Dietary coarseness resulted in approximately 16% lower gizzard pH, 21% greater villus heights, 27% lower crypt depths, 24% reduced branched-chain fatty acids, and 12% lower biogenic amines in the cecal digesta compared with broilers fed fine diets. In conclusion, feeding coarse particles improved broiler performance irrespective of digestibility of the diet. Hindgut protein fermentation can be reduced by coarse grinding of the diet.
    Biorefinery methods for separation of protein and oil fractions from rubber seed kernel
    Widyarani, R. ; Ratnaningsih, E. ; Sanders, J.P.M. ; Bruins, M.E. - \ 2014
    Industrial Crops and Products 62 (2014). - ISSN 0926-6690 - p. 323 - 332.
    aqueous enzymatic extraction - supercritical carbon-dioxide - hevea-brasiliensis seeds - biodiesel production - functional-properties - alpha-lactalbumin - nutritive-value - amino-acids - products - recovery
    Biorefinery of rubber seeds can generate additional income for farmers, who already grow rubber trees for latex production. The aim of this study was to find the best method for protein and oil production from rubber seed kernel, with focus on protein recovery. Different pre-treatments and oil separation methods were tested, and alkaline conditions were used to extract protein. Next to processes with subsequent oil and protein recovery, a one-step combined oil and protein extraction was tested. Our study showed that oil separation is not necessary to obtain high protein recovery, however most of the extracted oil is present as an emulsion. The origin of the seeds and their treatment on the plantation before processing were most important for high oil and protein recoveries, and in all cases tested had more influence on recoveries than its subsequent method of processing. Pressing the rubber seed kernel to separate the oil fraction followed by protein extraction from the press cake gives the highest protein recovery with satisfactory recovery for oil.
    Efficacy of dimethylglycine as a feed additive to improve broiler production
    Kalmar, I.D. ; Verstegen, M.W.A. ; Vanrompay, D. ; Maenner, K. ; Zentek, J. ; Iben, C. ; Leitgeb, R. ; Schiavone, A. ; Prola, L. ; Janssens, G. - \ 2014
    Livestock Science 164 (2014). - ISSN 1871-1413 - p. 81 - 86.
    amino-acids - n,n-dimethylglycine - supplementation - digestibility - performance - absorption - choline - betaine - diet
    Dimethylglycine (DMG) is a naturally occurring glycine derivative, which is useful as additive to broiler diets as it improves nutrient digestibility and reduces the development of broiler ascites syndrome. This study evaluated the efficacy of dietary DMG to enhance performance of broiler chickens. Three trials were conducted to evaluate the effect of dietary supplementation with 1 g Na DMG/kg on growth performance and carcass characteristics. In Trial 1, the effect of sex was also assessed in a 2×2 factorial arrangement of treatments. In Trials 1 (Germany), 2 (Austria), and 3 (Italy), each treatment consisted of 6, 12, and 11 replicate pens with 20, 15, and 16 one-day-old broiler chickens per pen, respectively. Dietary DMG supplementation resulted in improved feed conversion ratio (FCR) in the starter phase by 8.8% (P=0.004), 6.4% (P=0.001), and 4.8% (P=0.006) compared with the control diet in Trials 1, 2, and 3, respectively. The overall FCR improved in broiler chickens fed the diets supplemented with DMG by 3.8% and 4.1% in Trials 1 (P=0.007) and 3 (P=0.006), respectively. In addition, final body weight increased by 5.5% (P=0.001) in Trial 2 and production value improved by 6.8% (P=0.015) in Trial 1 by dietary DMG supplementation. Mortality in all trials was similar between dietary treatments. In all 3 trials, cold carcass weight and total meat yield were as well similar between broiler chickens fed the control and DMG diets. In Trial 1, dietary DMG had no effect on breast meat yield in male broiler chickens, but it increased breast meat yield in female broiler chickens (diet×sex, P=0.004). Organoleptic quality of roasted breast meat assessed only in Trial 2 was not affected by dietary treatments. In conclusion, dietary supplementation of DMG at 1 g Na DMG/kg can considerably improve s production performance in broiler chickens.
    Separation of digesta fractions complicates estimation of ileal digestibility using marker methods with Cr2O3 and Co-EDTA in broiler chickens
    Vries, S. de; Kwakkel, R.P. ; Pustjens, A.M. ; Kabel, M.A. ; Hendriks, W.H. ; Gerrits, W.J.J. - \ 2014
    Poultry Science 93 (2014)8. - ISSN 0032-5791 - p. 2010 - 2017.
    atomic-absorption spectrophotometry - gastrointestinal transit-time - carboxy methyl cellulose - nonstarch polysaccharides - soluble polysaccharide - feed ingredients - amino-acids - avian ceca - tract - food
    Marker methodologies to measure ileal and total tract digestibilities of diets varying in content and degradability of dietary fiber in broiler chickens were evaluated. Chromium sesquioxide (Cr2O3) and cobalt-ethylenediamine tetraacetic acid (Co-EDTA) were used as markers of solid and soluble fractions, respectively, and compared with digestibility values obtained with the total collection method. Groups of broilers (n = 17, 11 broilers/group) were assigned to a low-fiber diet or 1 of 2 high-fiber diets, the latter 2 containing 35% rapeseed meal (RSM). Pectolytic enzymes were added to one RSM diet to improve degradability of the fiber fraction. Excreta were quantitatively collected for 96 h, and contents from ileum and ceca were collected at slaughter at 29, 30, or 31 d of age. Chromium recovery in excreta ranged between 86 and 95%, whereas cobalt recovery was considerably lower (66 to 70%). Chromium:cobalt ratio was higher in ileal digesta than in feed. Hardly any chromium was found in the ceca, indicating that separation of the marker and specific digesta fractions occurs. Estimates of apparent total tract digestibility (ATTD) were lower when calculated using the marker method compared with the total collection method, particularly in high-fiber diets. Using Cr2O3 as a marker, differences were relatively small and effects due to enzyme addition were generally similar. Using Co-EDTA as a marker, ATTD of all components were lower compared with values obtained using the collection method (3 to 45 percentage units, P <0.001), likely related to the low Co recovery. When estimating apparent ileal digestibility (AID), separation of marker and digesta resulted in unrealistically high estimates for the digestibility of nonglucose polysaccharides (54 to 66%), exceeding ATTD values by 16 to 42 percentage units. Moreover, the effect of pectolytic enzyme addition on the AID of nonglucose polysaccharides was in the opposite direction when compared with total collection. The data illustrate that fractionation of digesta, particularly in high-fiber diets, complicates accurate AID measurements in broilers, regardless of the choice of markers used.
    Glutamic acid production from wheat by-products using enzymatic and acid hydrolysis
    Sari, Y.W. ; Alting, A.C. ; Floris, R. ; Sanders, J.P.M. ; Bruins, M.E. - \ 2014
    Biomass and Bioenergy 67 (2014). - ISSN 0961-9534 - p. 451 - 459.
    bio-based chemicals - amino-acids - protein - gluten - deamidation - biomass - solubility
    Glutamic acid (Glu) has potential as feedstock for bulk chemicals production. It has also been listed as one of the top twelve chemicals derived from biomass. Large amounts of cheaper Glu can be made available by enabling its production from biomass by-products, such as wheat dried distillers grains with solubles (DDGS) derived from ethanol production. The aim of this study was to develop a new method for Glu production from biomass. Wheat gluten was used to represent wheat DDGS. To reduce chemicals usage, several methods were evaluated. These included enzymatic, dilute acid, and a combination of enzymatic and dilute acid hydrolysis. The separate enzymatic and dilute acid hydrolysis (1 M HCl; 95 °C) resulted in yields of 48% and 46% Glu, respectively. However, the combination of enzymatic and dilute acid hydrolysis resulted in a much higher yield of 70% Glu and 10% pyroglutamic acid thereby opening up new possibilities for the industrial production of Glu from biomass
    Critical parameters in cost-effective alkaline extraction for high protein yield from leaves
    Zhang, C. ; Sanders, J.P.M. ; Bruins, M.E. - \ 2014
    Biomass and Bioenergy 67 (2014). - ISSN 0961-9534 - p. 466 - 472.
    leaf protein - functional-properties - chemical-composition - amino-acids - tea-leaves - biomass - concentrate - refinery - feed
    Leaves are potential resources for feed or food, but their applications are limited due to a high proportion of insoluble protein and inefficient processing. To overcome these problems, parameters of alkaline extraction were evaluated using green tea residue (GTR). Protein extraction could be maximized to 95% of total protein, and, after precipitation by pH adjustment to 3.5, 85% of extracted protein was recovered with a purity of 52%. Temperature, NaOH amount, and extraction time are the protein yield determining parameters, while pH and volume of extraction liquid are critical parameters for production cost. The cost of energy and chemicals for producing 1 t GTR proteins is minimized to 102€, and its nutritional value is comparable to soybean protein. Furthermore, this technology was successfully applied to other sources of biomass and has potential to be used as a part of an integrated bio-refinery process.
    Effect of Processing on the Quality of Pineapple Juice
    Hounhouigan, M.H. ; Linnemann, A.R. ; Soumanou, M.M. ; Boekel, M.A.J.S. van - \ 2014
    Food Reviews International 30 (2014)2. - ISSN 8755-9129 - p. 112 - 133.
    orange juice - fruit juices - ascorbic-acid - ananas-comosus - food-industry - amino-acids - saccharomyces-cerevisiae - phytochemical properties - neosartorya-fischeri - thermal-degradation
    Pineapple processing plays an important role in juice preservation. Because the quality of the pineapple juice is affected by the processing technology applied, the effects of pasteurization and other preservation methods on the overall juice quality were discussed. During juice processing, microorganisms are destroyed and chemical changes occur. To optimize processing conditions, knowledge of the kinetics of these reactions is needed, but as of yet, data on the degradation of the amino acids and vitamin C and the change in sugar contents during pineapple juice pasteurization are scanty. Furthermore, the kinetics of hydroxymethylfurfural production should be investigated by a precise technique such as high-performance liquid chromatography.
    An isotope dilution model for partitioning phenylalanine and tyrosine uptake by the mammary gland of lactating dairy cows
    Crompton, L.A. ; France, J. ; Reynolds, C.K. ; Mills, J.A.N. ; Hanigan, M.D. ; Ellis, J.L. ; Bannink, A. ; Bequette, B.J. ; Dijkstra, J. - \ 2014
    Journal of Theoretical Biology 359 (2014). - ISSN 0022-5193 - p. 54 - 60.
    milk protein-synthesis - amino-acids - metabolism - casein - goats - infusions - ruminant - flux
    An isotope dilution model for partitioning phenylalanine and tyrosine uptake by the mammary gland of the lactating dairy cow is constructed and solved in the steady state. The model contains four intracellular and four extracellular pools and conservation of mass principles is applied to generate the fundamental equations describing the behaviour of the system. The experimental measurements required for model solution are milk secretion and plasma flow rate across the gland in combination with phenylalanine and tyrosine concentrations and plateau isotopic enrichments in arterial and venous plasma and free and protein bound milk during a constant infusion of [1-13C]phenylalanine and [2,3,5,6-2H]tyrosine tracer. If assumptions are made, model solution enables determination of steady state flows for phenylalanine and tyrosine inflow to the gland, outflow from it and bypass, and flows representing the synthesis and degradation of constitutive protein and hydroxylation. The model is effective in providing information about the fates of phenylalanine and tyrosine in the mammary gland and could be used as part of a more complex system describing amino acid metabolism in the whole ruminant
    The impact of protein supplementation on cognitive performance in frail elderly
    Zwaluw, N.L. van der; Rest, O. van de; Tieland, C.A.B. ; Adam, J.J. ; Hiddink, G.J. ; Loon, L.J.C. van; Groot, C.P.G.M. de - \ 2014
    European Journal of Nutrition 53 (2014)3. - ISSN 1436-6207 - p. 803 - 812.
    older-adults - alzheimers-disease - nutritional-status - dietary-protein - whey-protein - amino-acids - task-force - healthy - carbohydrate - decline
    Purpose Maintenance of cognitive abilities is important for elderly to stay independent. With the aging of the population, the call for modifiable factors is emerging. Dietary protein might improve cognitive performance; however, this has hardly been studied. Therefore, we studied the impact of 24-week dietary protein supplementation on cognitive performance in pre-frail and frail elderly people. Methods Pre-frail and frail elderly subjects, according to the Fried criteria, randomly received a protein drink containing 15 g protein or a placebo drink twice a day. Cognitive performance was measured at baseline and after 24 weeks by means of a sensitive neuropsychological test battery. In addition, reaction time was assessed after both 12 and 24 weeks of intervention. Domain scores were calculated for the domains episodic memory, attention and working memory, information processing speed, and executive functioning. Analyses of covariance were used to determine differences between groups. Linear mixed models were used to determine differences in reaction time over time and per treatment. Results In total, 65 subjects (79 ± 8 years) with a median Mini-Mental State Examination score of 28 (interquartile range 26–30) were included. Reaction time improved more in the protein group (68 ms) than in the placebo group (18 ms, P = 0.03). Dietary protein had no significant effect on any of the cognitive domain scores. Conclusions Protein supplementation might improve reaction time performance in pre-frail and frail elderly, but did not improve other cognitive functions.
    Hypothalamic food intake regulation in a cancer-cachectic mouse model
    Dwarkasing, J.T. ; Dijk, M. van; Dijk, F.J. ; Boekschoten, M.V. ; Faber, J. ; Argiles, J.M. ; Laviano, A. ; Müller, M.R. ; Witkamp, R.F. ; Norren, K. van - \ 2014
    Journal of cachexia, sarcopenia and muscle 5 (2014)2. - ISSN 2190-5991 - p. 159 - 169.
    tumor-bearing rats - neuropeptide-y - colon-26 adenocarcinoma - serotonergic system - insulin-resistance - brain-serotonin - murine model - amino-acids - cachexia - mice
    Background Appetite is frequently affected in cancer patients leading to anorexia and consequently insufficient food intake. In this study, we report on hypothalamic gene expression profile of a cancer-cachectic mouse model with increased food intake. In this model, mice bearing C26 tumour have an increased food intake subsequently to the loss of body weight. We hypothesise that in this model, appetite-regulating systems in the hypothalamus, which apparently fail in anorexia, are still able to adapt adequately to changes in energy balance. Therefore, studying changes that occur on appetite regulators in the hypothalamus might reveal targets for treatment of cancer-induced eating disorders. By applying transcriptomics, many appetite-regulating systems in the hypothalamus could be taken into account, providing an overview of changes that occur in the hypothalamus during tumour growth. Methods C26-colon adenocarcinoma cells were subcutaneously inoculated in 6 weeks old male CDF1 mice. Body weight and food intake were measured three times a week. On day 20, hypothalamus was dissected and used for transcriptomics using Affymetrix chips. Results Food intake increased significantly in cachectic tumour-bearing mice (TB), synchronously to the loss of body weight. Hypothalamic gene expression of orexigenic neuropeptides NPY and AgRP was higher, whereas expression of anorexigenic genes CCK and POMC were lower in TB compared to controls. In addition, serotonin and dopamine signalling pathways were found to be significantly altered in TB mice. Serotonin levels in brain showed to be lower in TB mice compared to control mice, while dopamine levels did not change. Moreover, serotonin levels inversely correlated with food intake. Conclusions Transcriptomic analysis of the hypothalamus of cachectic TB mice with an increased food intake showed changes in NPY, AgRP and serotonin signalling. Serotonin levels in the brain showed to correlate with changes in food intake. Further research has to reveal whether targeting these systems will be a good strategy to avoid the development of cancer-induced eating disorders
    Factors Causing Compositional Changes in Soy Protein Hydrolysates and Effects on Cell Culture Functionality
    Gupta, A.J. ; Gruppen, H. ; Maes, D. ; Boots, J.W. ; Wierenga, P.A. - \ 2013
    Journal of Agricultural and Food Chemistry 61 (2013)45. - ISSN 0021-8561 - p. 10613 - 10625.
    hamster ovary cells - recombinant therapeutic protein - maillard reaction-products - metabolic flux analysis - in-vitro digestibility - amino-acids - trypsin-inhibitor - soybean meals - cho-cells - chemical-composition
    Soy protein hydrolysates significantly enhance cell growth and recombinant protein production in cell cultures. The extent of this enhancement in cell growth and IgG production is known to vary from batch to batch. This can be due to differences in the abundance of different classes of compounds (e.g., peptide content), the quality of these compounds (e.g., glycated peptides), or the presence of specific compounds (e.g., furosine). These quantitative and qualitative differences between batches of hydrolysates result from variation in the seed composition and seed/meal processing. Although a considerable amount of literature is available that describes these factors, this knowledge has not been combined in an overview yet. The aim of this review is to identify the most dominant factors that affect hydrolysate composition and functionality. Although there is a limited influence of variation in the seed composition, the overview shows that the qualitative changes in hydrolysate composition result in the formation of minor compounds (e.g., Maillard reaction products). In pure systems, these compounds have a profound effect on the cell culture functionality. This suggests that the presence of these compounds in soy protein hydrolysates may affect hydrolysate functionality as well. This influence on the functionality can be of direct or indirect nature. For instance, some minor compounds (e.g., Maillard reaction products) are cytotoxic, whereas other compounds (e.g., phytates) suppress protein hydrolysis during hydrolysate production, resulting in altered peptide composition, and, thus, affect the functionality.
    The Positive Impact of the Early-Feeding of a Plant-Based Diet on Its Future Acceptance and Utilisation in Rainbow Trout
    Geurden, I. ; Borchert, P. ; Balasubramanian, M.N. ; Schrama, J.W. ; Dupont-Nivet, M. ; Quillet, E. ; Kaushik, S.J. ; Panserat, S. ; Médale, F. - \ 2013
    PLoS ONE 8 (2013)12. - ISSN 1932-6203 - 9 p.
    salmon oncorhynchus-kisutch - atlantic salmon - amino-acids - epigenetic modifications - growth-performance - homing migration - body-composition - oil replacement - ration level - mykiss
    Sustainable aquaculture, which entails proportional replacement of fish-based feed sources by plant-based ingredients, is impeded by the poor growth response frequently seen in fish fed high levels of plant ingredients. This study explores the potential to improve, by means of early nutritional exposure, the growth of fish fed plant-based feed. Rainbow trout swimup fry were fed for 3 weeks either a plant-based diet (diet V, V-fish) or a diet containing fishmeal and fish oil as protein and fat source (diet M, M-fish). After this 3-wk nutritional history period, all V- or M-fish received diet M for a 7-month intermediate growth phase. Both groups were then challenged by feeding diet V for 25 days during which voluntary feed intake, growth, and nutrient utilisation were monitored (V-challenge). Three isogenic rainbow trout lines were used for evaluating possible family effects. The results of the V-challenge showed a 42% higher growth rate (P = 0.002) and 30% higher feed intake (P = 0.005) in fish of nutritional history V compared to M (averaged over the three families). Besides the effects on feed intake, V-fish utilized diet V more efficiently than M-fish, as reflected by the on average 18% higher feed efficiency (P = 0.003). We noted a significant family effect for the above parameters (P,0.001), but the nutritional history effect was consistent for all three families (no interaction effect, P.0.05). In summary, our study shows that an early shortterm exposure of rainbow trout fry to a plant-based diet improves acceptance and utilization of the same diet when given at later life stages. This positive response is encouraging as a potential strategy to improve the use of plant-based feed in fish, of interest in the field of fish farming and animal nutrition in general. Future work needs to determine the persistency of this positive early feeding effect and the underlying mechanisms.
    Heterodera schachtii nematodes interfere with aphid-plant relations on Brassica oleracea
    Hol, W.H.G. ; Boer, W. de; Termorshuizen, A.J. ; Meyer, K.M. ; Schneider, J.H.M. ; Putten, W.H. van der; Dam, N.M. - \ 2013
    Journal of Chemical Ecology 39 (2013)9. - ISSN 0098-0331 - p. 1193 - 1203.
    multitrophic interactions - brevicoryne-brassicae - myzus-persicae - herbivore interactions - mediated interactions - indole glucosinolate - shoot herbivores - soybean aphid - jasmonic acid - amino-acids
    Aboveground and belowground herbivore species modify plant defense responses differently. Simultaneous attack can lead to non-additive effects on primary and secondary metabolite composition in roots and shoots. We previously found that aphid (Brevicoryne brassicae) population growth on Brassica oleracea was reduced on plants that were infested with nematodes (Heterodera schachtii) prior (4 weeks) to aphid infestation. Here, we examined how infection with root-feeding nematodes affected primary and secondary metabolites in the host plant and whether this could explain the increase in aphid doubling time from 3.8 to 6.7 days. We hypothesized that the effects of herbivores on plant metabolites would depend on the presence of the other herbivore and that nematode-induced changes in primary metabolites would correlate with reduced aphid performance. Total glucosinolate concentration in the leaves was not affected by nematode presence, but the composition of glucosinolates shifted, as gluconapin concentrations were reduced, while gluconapoleiferin concentrations increased in plants exposed to nematodes. Aphid presence increased 4-methoxyglucobrassicin concentrations in leaves, which correlated positively with the number of aphids per plant. Nematodes decreased amino acid and sugar concentrations in the phloem. Aphid population doubling time correlated negatively with amino acids and glucosinolate levels in leaves, whereas these correlations were non-significant when nematodes were present. In conclusion, the effects of an herbivore on plant metabolites were independent of the presence of another herbivore. Nematode presence reduced aphid population growth and disturbed feeding relations between plants and aphids.
    Substantial differences between organ and muscle specific tracer incorporation rates in a lactating dairy cow
    Burd, N.A. ; Hamer, H.M. ; Pennings, B. ; Pellikaan, W.F. ; Senden, J.M.G. ; Gijsen, A. ; Loon, L.J.C. van - \ 2013
    PLoS ONE 8 (2013)6. - ISSN 1932-6203 - 9 p.
    tissue protein-synthesis - intrinsically labeled milk - human-nutrition research - amino-acids - resistance exercise - skeletal-muscle - neonatal pigs - whey-protein - elderly-men - whole-body
    We aimed to produce intrinsically L-[1-13C]phenylalanine labeled milk and beef for subsequent use in human nutrition research. The collection of the various organ tissues after slaughter allowed for us to gain insight into the dynamics of tissue protein turnover in vivo in a lactating dairy cow. One lactating dairy cow received a constant infusion of L-[1-13C]phenylalanine (450 µmol/min) for 96 h. Plasma and milk were collected prior to, during, and after the stable isotope infusion. Twenty-four hours after cessation of the infusion the cow was slaughtered. The meat and samples of the various organ tissues (liver, heart, lung, udder, kidney, rumen, small intestine, and colon) were collected and stored. Approximately 210 kg of intrinsically labeled beef (bone and fat free) with an average L-[1-13C]phenylalanine enrichment of 1.8±0.1 mole percent excess (MPE) was obtained. The various organ tissues differed substantially in L-[1-13C]phenylalanine enrichments in the tissue protein bound pool, the highest enrichment levels were achieved in the kidney (11.7 MPE) and the lowest enrichment levels in the skeletal muscle tissue protein of the cow (between 1.5–2.4 MPE). The estimated protein synthesis rates of the various organ tissues should be regarded as underestimates, particularly for the organs with the higher turnover rates and high secretory activity, due to the lengthened (96 h) measurement period necessary for the production of the intrinsically labeled beef. Our data demonstrates that there are relatively small differences in L-[1-13C]phenylalanine enrichments between the various meat cuts, but substantial higher enrichment values are observed in the various organ tissues. We conclude that protein turnover rates of various organs are much higher when compared to skeletal muscle protein turnover rates in large lactating ruminants.
    Main Phenolic Compounds of the Melanin Biosynthesis Pathway in Bruising-Tolerant and Bruising-Sensitive Button Mushroom (Agaricus bisporus) Strains
    Weijn, A. ; Berg-Somhorst, B.P.M. van de; Slootweg, J.C. ; Vincken, J.P. ; Gruppen, H. ; Wichers, H.J. ; Mes, J.J. - \ 2013
    Journal of Agricultural and Food Chemistry 61 (2013)34. - ISSN 0021-8561 - p. 8224 - 8231.
    polyphenol oxidase - fungal melanins - amino-acids
    Browning is one of the most common postharvest changes in button mushrooms, which often results in economic losses. Phenolic compounds, which are associated with browning, were extracted from the nonbruised and bruised skin tissue of various button mushrooms with a sulfite-containing solution and analyzed with UHPLC-PDA-MS. In total, 34 phenolic compounds were detected. Only small differences in the total phenolic content between bruising-tolerant and -sensitive strains were observed. The contents of ¿-l-glutaminyl-4-hydroxybenzene (GHB) and ¿-l-glutaminyl-3,4-dihydroxybenzene (GDHB) correlated with bruising sensitivity; for example, R2 values of 0.85 and 0.98 were found for nonbruised brown strains, respectively. In nonbruised skin tissue of the strains with brown caps, the GHB and GDHB contents in sensitive strains were on average 20 and 15 times higher, respectively, than in tolerant strains. GHB and GDHB likely participate in the formation of brown GHB–melanin, which seemed to be the predominant pathway in bruising-related discoloration of button mushrooms.
    Identification of biomarkers for intake of protein from meat, dairy products and grains: a controlled dietary intervention study
    Altorf-van der Kuil, W. ; Brink, E.J. ; Boetje, M. ; Siebelink, E. ; Bijlsma, S. ; Engberink, M.F. ; Tome, D. ; Bakker, S.J. ; Baak, M.A. van; Geleijnse, J.M. ; Veer, P. van 't - \ 2013
    The British journal of nutrition 110 (2013)5. - ISSN 0007-1145 - p. 810 - 822.
    discriminant-analysis - nitrogen isotopes - urinary-excretion - amino-acids - 3-methylhistidine - values - muscle - milk
    In the present controlled, randomised, multiple cross-over dietary intervention study, we aimed to identify potential biomarkers for dietary protein from dairy products, meat and grain, which could be useful to estimate intake of these protein types in epidemiological studies. After 9 d run-in, thirty men and seventeen women (22 (sd 4) years) received three high-protein diets (aimed at approximately 18 % of energy (en%)) in random order for 1 week each, with approximately 14 en% originating from either meat, dairy products or grain. We used a two-step approach to identify biomarkers in urine and plasma. With principal component discriminant analysis, we identified amino acids (AA) from the plasma or urinary AA profile that were distinctive between diets. Subsequently, after pooling total study data, we applied mixed models to estimate the predictive value of those AA for intake of protein types. A very good prediction could be made for the intake of meat protein by a regression model that included urinary carnosine, 1-methylhistidine and 3-methylhistidine (98 % of variation in intake explained). Furthermore, for dietary grain protein, a model that included seven AA (plasma lysine, valine, threonine, a-aminobutyric acid, proline, ornithine and arginine) made a good prediction (75 % of variation explained). We could not identify biomarkers for dairy protein intake. In conclusion, specific combinations of urinary and plasma AA may be potentially useful biomarkers for meat and grain protein intake, respectively. These findings need to be cross-validated in other dietary intervention studies.
    Polymerisation of Beta-alanine through catalytic ester-amide exchange
    Steunenberg, P. ; Könst, P.M. ; Scott, E.L. ; Franssen, M.C.R. ; Zuilhof, H. ; Sanders, J.P.M. - \ 2013
    European Polymer Journal 49 (2013)7. - ISSN 0014-3057 - p. 1773 - 1781.
    nitrogen-containing chemicals - ring-opening polymerization - amino-acids - biobased production - cyanophycin - peptides - esterification - acrylamide - polymers - mild
    Herein we present the use of group (IV) metal alkoxides as catalysts for the polymerisation of esters of p-alanine and its derivatives. The influence of different group (IV) metal alkoxides, different esters, temperature and solvents on the polymerisation are investigated. The order in which the group (IV) metal alkoxides catalyse the polymerisation is: Hf(Ot-Bu)(4) - >= Zr(Ot-Bu)(4) > Ti(Oi-Pr) 4 > Ti(On-Bu)(4). Polymers with the highest degree of polymerisation are obtained performing a neat polymerisation of p-alanine methyl ester in the presence of Hf(Ot-Bu)(4) as a catalyst at 50 degrees C. The polymerisation can also be carried out efficiently in solution, in different solvents and at higher reaction temperatures. This method could also be applied for the formation of other polypeptides. (c) 2013 Elsevier Ltd. All rights reserved.
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