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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    FeedOmics, an approach to evaluate the functional properties of protein containing feed ingredients
    Kar, Soumya K. - \ 2017
    Wageningen University. Promotor(en): M.A. Smits; J.M. Wells, co-promotor(en): A.J.M. Jansman; D. Schokker. - Wageningen : Wageningen University - ISBN 9789463434461 - 254
    compound feeds - ingredients - protein sources - proteins - functional properties - metabolism - feed formulation - protein digestion - proteomics - digestive tract - nutrition physiology - animal nutrition - livestock feeding - mengvoer - ingrediënten - eiwitbronnen - eiwitten - functionele eigenschappen - metabolisme - voersamenstelling - eiwitvertering - eiwitexpressieanalyse - spijsverteringskanaal - voedingsfysiologie - diervoeding - veevoeding

    This thesis presents FeedOmics approach as a toolkit, to evaluate (novel) protein containing feed ingredients of different origin considering both their nutritional and functional value in terms of their capacity to support or modify nutrient supply, the animal’s physiology, tissue development and functioning. Such knowledge may contribute to introduce novel and/or alternative protein containing feed ingredients in the diet of livestock, thus creating a sustainable food supply for growing human population.

    Protein quaternary structure and aggregation in relation to allergenicity
    Boxtel, E.L. van - \ 2007
    Wageningen University. Promotor(en): Harry Gruppen, co-promotor(en): Ben van den Broek; S.J. Koppelman. - [S.l.] : S.n. - ISBN 9789085047827 - 152
    allergenen - eiwitten - denaturatie - chemische structuur - voedselallergieën - sojaeiwit - aardnoteneiwit - paranoten - eiwitvertering - allergens - proteins - denaturation - chemical structure - food allergies - soya protein - groundnut protein - Brazil nuts - protein digestion
    In order to induce systemic food allergic reactions in humans, proteins after digestion in the human gastro-intestinal tract should still be able to bind IgE. The aim of the work presented in this thesis was to determine the effects of heating on the structure and digestibility of cupin and prolamin food allergens from peanuts, Brazil nuts and soybeans and to determine the effects of digestion on the IgE binding capacity of these allergens. Representative allergen preparations were purified prior to the investigations. To this end, a large-scale purification method was developed for the purification of Brazil nut allergen Ber e 1, comprising its complete isoform pool. The denaturation temperature of the latter allergen at the common pH values of foods (5-7) appeared to be very high. As a result, this protein is assumed not to be denatured during common food processing and to be digested (mainly) in its native form. The native form of Ber e 1 is known to have a high stability towards peptic digestion, which likely explains the allergenicity of this protein. The representative quaternary structure of vicilin allergen Ara h 1 from peanuts appeared to be an oligomeric structure, in which the protein is assumed to interact with proanthocyanidins via a specific distribution of proline residues on its surface. Heat-induced aggregation prior to peptic hydrolysis under in vitro conditions did not affect the digestibility of Ara h 1, whereas heat-induced aggregation of legumin allergens Ara h 3 from peanuts and glycinin from soybeans (slightly) decreased the digestion rates. Regardless of pre-heating, the IgE binding capacity of the latter allergens diminished fast during pepsin digestion. As a result, in terms of systemic food allergic reactions, legumin allergens from peanuts and soybeans might not be very important allergens. Vicilin allergen Ara h 1 could still bind IgE after prolonged peptic digestion. Two pepsin-resistant epitopes were deduced and indications for four additional pepsin-resistant epitopes are presented. These epitopes are all situated on the unique N-terminal part of the allergen, which might explain why allergic reactions to peanuts are often severe, compared to other legume allergies.
    Limiting factors for the enzymatic accessibility of soybean protein
    Fischer, M. - \ 2006
    Wageningen University. Promotor(en): Harry Gruppen; Fons Voragen. - [S.l.] : S.n. - ISBN 9789085044963 - 139
    sojaeiwit - hydrolyse - aggregatie - koolhydraten - eiwitextractie - eiwitvertering - eiwitverteerbaarheid - peptiden - soya protein - hydrolysis - aggregation - carbohydrates - protein extraction - protein digestion - protein digestibility - peptides
    Soy is a commonly used ingredient is food and animal feed. With particular focus on the in-soluble fractions, this thesis deals with the effects of proteases and carbohydrate degrading enzymes on different soybean meals subjected to different extent of heating. The primary aim is to improve the understanding of enzymatic hydrolysis of SBM with emphasis on proteins and to identify barriers limiting the efficiency of the process. The results show that aggregation behavior of peptides during enzymatic processing of soy proteins is potentially a limiting factor for efficacy of protein extraction. Surprisingly, it is also demonstrated that aggregation is not limited to in vitro incubations, but is also occurring in vivo in the digestive system of pigs.
    Phytase studies in pigs and poultry: effect on protein digestion and energy utilization
    Kies, A.K. - \ 2005
    Wageningen University. Promotor(en): Martin Verstegen, co-promotor(en): Walter Gerrits. - s.l. : S.n. - ISBN 9789085042228 - 148
    varkens - pluimvee - fytase - voedersupplementen - eiwitvertering - energiegebruik - varkensvoeding - pluimveevoeding - diervoeding - voedingsfysiologie - pigs - poultry - phytase - feed supplements - protein digestion - energy consumption - pig feeding - poultry feeding - animal nutrition - nutrition physiology
    Phytase is applied for improving digestibility of phosphorus in pig and poultry diets. Indepen-dently, phytase also improves animal performance. The mechanisms to explain this effect were investigated and quantified. Protein can be complexed with phytate, especially under the acid conditions that occurs in the stomach of animals. Dietary phytase supplementation pre-vents formation of such complexes or, if such complexes are formed, helps to release protein faster and to a larger extent from phytate. Consequently, protein digestibility may increase. This effect was confirmed in a meta-analysis of digestibility experiments, both in poultry and pigs. The higher protein digestibility explains, only in part, the improved performance. In poultry, the apparent metabolizable energy level increased with dietary phytase, mainly as the result of higher protein and fat digestion. Because in literature no effect of phytase on energy digestibility in pigs was shown, post-absorptive energy utilization was investigated. Using indirect calorimetry, no clear effect of phytase could be shown on energy partitioning. Phytase improved, however, energy utilization during the first two weeks post-weaning of ad libitum fed piglets. This may indicate that adaptation of piglets is somewhat facilitated by phytase. In an experiment with restrictedly-fed piglets, three weeks post-weaning, energy digestibility increased with phytase, but not energy metabolizability. A number of observations indicated, however, that energy metabolism of the piglets was affected. Processes that increase or de-crease heat production balance each other out. Phytase increased digestibility of minerals considerably, including the monovalent cations sodium and potassium. Mineral absorption and excretion are, in part, active processes, increasing heat production. Using a mathematical model, this effect was estimated at about 1% of energy requirements for maintenance. A lower energy requirement may result from a reduced produc-tion of endogenous protein. In growing pigs, dietary phytase supplementation decreased gastric mucin production. Possibly, the for-mation of inositol mono-, di- or tri-phosphates may act positively on the growth of animals, but this remains to be confirmed. In conclusion, phytase improved digestibility of amino acids, both in poultry and pigs. It also improved energy metabolizability in poultry. Energy utilization in pigs is probably affected, but the mechanism needs further clarification and quantification.
    Nutritive value of browses as protein supplement(s) to poor quality roughages
    Kaitho, R.J. - \ 1997
    Agricultural University. Promotor(en): S. Tamminga; N.N. Umunna; J. van Bruchem. - S.l. : Kaitho - ISBN 9789054857358 - 189
    herkauwers - diervoeding - voedingswaarde - voedersupplementen - eiwitvertering - smakelijkheid - veevoeder - eiwitten - ruminants - animal nutrition - nutritive value - feed supplements - protein digestion - palatability - fodder - proteins

    In tropical and subtropical regions, pasture grasses and cereal residues are frequently low in nutrients especially protein and therefore cannot support high levels of ruminant production. Many browse species are endowed with high levels of protein and hence suitable as supplements. The objective of this study was to develop indices that could be used to predict nutritive value of browses as supplements to poor quality roughage basal diets. Experiments were carried out to address issues related to establishing an experimental protocol for screening large browse species in feeding trials, the effect of animal species and the proportion of browse in the diet. Different methods to estimate protein digestion in small intestine were compared and data of individual browses collected. The palatability method developed was suitable for evaluating palatability of large numbers of browses under stall feeding condition. If palatability is done to predict long term intake a period of 5 to 8 days should be allowed. Classification of browses using either chemical composition, degradability or gas production characteristics led to different cluster groups than when palatability was used. Tannins had beneficial attributes at moderate levels and detrimental effect at high levels. The optimum level of browse supplementation was 30 to 45% of the ration dry matter. Browses need to be further studied since some of the secondary chemicals contained may affect reproduction.

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