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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    Wat moet je doen en laten als je gezonder wilt
    Witkamp, R.F. - \ 2015
    Universiteit van Nederland
    diëten - voeding en gezondheid - voedselwetenschappen - fysiologie - voedselproducten - gezondheidsvoedsel - gezondheidsbevordering - voedingsonderzoek - diets - nutrition and health - food sciences - physiology - food products - health foods - health promotion - nutrition research
    Slik jij de praatjes van afslankguru's als zoete koek? Ken jij alle diëten uit je hoofd? Renger Witkamp, hoogleraar Voeding en Farmacologie (Wageningen UR) bekijkt al deze hypes met een nuchtere en wetenschappelijke blik. Na dit praatje kun je alles wat je voorgeschoteld krijgt in de media over je gezondheid beter in perspectief plaatsen.
    Microalgae diets for landbased aquaculture of the cockle Cerastoderma edule: impacts of dietary fatty acids on growth
    Reis Batista, I.C. dos - \ 2015
    Wageningen University. Promotor(en): Aad Smaal, co-promotor(en): Johan Kamermans; R.H. Wijffels. - Wageningen : Wageningen University - ISBN 9789462575875 - 132
    schaaldieren - schaal- en schelpdierenteelt - algen - voedering - voersamenstelling - diëten - vetzuren - groei - tanks - plassen - aquacultuur - shellfish - shellfish culture - algae - feeding - feed formulation - diets - fatty acids - growth - tanks - ponds - aquaculture

    Land-based shellfish culture as a part of a multi-trophic aquaculture systems has yet to be implemented in Europe. Recently the pilot project Zeeuwse Tong (The Netherlands) evaluated the feasibility of a system of fish (Dover sole), ragworms, phytoplankton and bivalves. This thesis focused on the dietary fatty acids impact on growth, survival and fatty acid composition of juveniles (shell length >5mm) of the common cockle Cerastoderma edule, for land-based culture.

    Dietary fatty acids were chosen as the main nutritional research subject given the existing literature indicating their importance for reproduction, and growth and survival of larvae, post-larvae, spat and seed of most bivalves. However, since grow-out of juvenile cockles in land-based aquaculture is not common, no information is available on the dietary fatty acid requirements of juveniles. To determine if the presence of specific fatty acids is more important for growth and survival of juvenile cockles than the total amount of dietary fatty acids supplied, least cost linear programming was used to design live microalgae diets. Monocultures of indigenous algae were grown under controlled conditions and sampled to determine their quality in terms of dry weight, organic matter, lipid and fatty acids composition. These differences in biochemical composition of the microalgae were used in a least-cost programming software, and allowed the formulation of three diets with different fatty acid contents, but similar dry weight, organic matter, lipid and total fatty acid content. The formulated diets were then used to determine the importance of dietary fatty acids for growth, survival and fatty acid composition of juvenile cockles (Cerastoderma edule). Juvenile cockles (6.24±0.04 mm) were constantly fed live microalgal diets with similar lipid, organic matter and total fatty acid contents but different individual fatty acid concentrations: high-EPA, no-DHA and low-ARA diets. Growth was positively affected by high-EPA and low-ARA diets, whereas no significant growth was observed for the no-DHA diet. However, high mortality of cockles fed no-DHA diet and the low absorption efficiency and clearance rate of this diet indicate that this diet is unsuitable for juvenile cockles. In balanced diets with EPA and DHA, lower concentrations of ARA did not limit growth. The combination of EPA and DHA in a live microalgae diet was beneficial for the growth and survival of juvenile cockles, but no conclusion on the importance of supplying only EPA could be made. To address this, an additional growth experiment was designed. Growth and fatty acid profiles of juveniles cockles were determined after 28 days of feeding diets:1) with EPA 2) with DHA; 3) with EPA and DHA from a mixture of a diatom with a green algae; 4) with EPA and DHA from a mixture of the two green algae and 5) without long-chain (>C20) fatty acids. Significantly higher growth rate was observed with the treatment rich in EPA, while the lowest growth rates were found in without EPA. These results indicate that EPA is necessary for the short-term growth of cockles. Moreover, the fatty acid profile of the polar lipids confirmed that, like most marine invertebrates, juvenile C. edule are not able to biosynthesize EPA and DHA from 18:3n-3 but are capable of biosynthesizing diene and triene NMI fatty acids. The occurrence of the NMI fatty acids was diet related, thus refuting the possibility of production of NMI as replacement for EPA and DHA.

    Furthermore, in order to develop land-based culture of cockles it is crucial to have a supply of high quality live microalgal diets produced with minimum effort. Therefore, the use of simplified microalgae media, with different nitrogen sources (nitrate or ammonium) and molar N:P ratio, phosphorus, silica, iron, manganese and vitamins were also investigated. Chaetoceros muelleri, a marine diatom that was chosen given its robustness and quality as food for juvenile cockles, reacted positively to all simplified media. At the exponential phase, all cultures had reached similar cellular concentrations and dry weight productions. Cultures grown on ammonium media had a longer cultivation period, 20 days. Considering dry-weight production, culture duration, nutrient efficiency and lipid composition, the simplified media containing ammonium, phosphorus, silica, iron, manganese and vitamins proved to be a viable choice for batch culture of C. muelleri. The choice between these two media depends on the final purpose of the microalgae cultures and whether lipid contents (NH49:1), dry weight biomass (NH425:1) or nitrogen input and output (NH49:1) are more important.

    In this thesis it was demonstrated that mono-algal diets with high EPA, as well as mixed live microalgae diets with high EPA and DHA contents proved to be suitable diets for C. edule juveniles. In addition, a positive relation between growth and the amount fed was found. The growth rates of the cultured cockles in this thesis are in accordance with the rates observed under natural conditions. The use of the simplified microalgae culture medium tested represents a significant decrease in the cost and preparation of the medium, as well as longer production and harvest periods, while maintaining microalgae quality. These results indicate that land-based aquaculture of cockles and microalgae is therefore a promising venture, with potential for expansion.

    Fishing for food : feeding ecology of harbour porpoises Phocoena phocoena and white-beaked dolphins Lagenorhynchus albirostris in Dutch waters
    Jansen, O.E. - \ 2013
    Wageningen University. Promotor(en): Peter Reijnders, co-promotor(en): Marten Scheffer. - S.l. : s.n. - ISBN 9789461734228 - 173
    phocoena - lagenorhynchus - dolfijnen - voedingsecologie - diëten - kustwateren - noordzee - oosterschelde - nederland - phocoena - lagenorhynchus - dolphins - feeding ecology - diets - coastal water - north sea - eastern scheldt - netherlands

    Harbour porpoises and white-beaked dolphins are the most common small cetaceans in the North Sea and Dutch coastal waters. The distribution and relative abundance of harbour porpoises and white-beaked dolphins from the Dutch coastal waters has changed significantly over the past decades. This thesis describes the past and present feeding ecology of these two species in Dutch coastal waters and investigates whether changes in abundance and relative distribution of porpoises reflect changes in their foodbase. For porpoises, three techniques for dietary analyses were combined, including stomach contents-, stable isotope- and fatty acid analysis, providing the most detailed description of their diet in time and space, elucidating differences between their short- and longer term diet.

    Stable isotope analysis (δ13C and δ15N) were carried out in bone and muscle samples collected from porpoises stranded along the Dutch coast. Muscle δ15N values revealed that neonatal enrichment occurred and that larger porpoises, in particular males, seem to feed on lower trophic level species, compared to smaller individuals. Also bone δ15N values show that larger animals had fed on lower trophic levels in distant times. Seasonal variation in bone δ15N and δ13C values revealed two distinct groups of porpoises along the Dutch coast, a winter group (mainly males) that migrated from neighbouring regions and a Dutch subpopulation in summer (Chapter 2).

    To assess the contribution of prey species to the porpoises’ diet, stable isotope analysis in both porpoise muscle and prey were carried out. With the use of a mixing model (Stable Isotope Analysis in R, SIAR), we revealed that 70-83% of the diet of porpoises consisted mainly of poor cod, mackerel, greater sandeel lesser sandeel, sprat and gobies. This highlights a higher importance of pelagic, schooling species in the porpoises’ diet compared to stomach contents, where 90.5% of the diet consisted of gobies, whiting, lesser sandeel, herring, cod and sprat. Porpoises thus also feed offshore on pelagic, schooling species, while they feed closer to shore on more benthic and demersal species shortly before they strand. This could be due to the distribution of prey species as well as differences in behaviour of porpoises and their prey between the coastal zone and offshore waters (Chapter 3).

    The use of Quantitative Fatty Acid Analysis (QFASA) showed that the diet of porpoises consisted mainly of gobies, mackerel, smelt, herring and dragonet, pointing towards profound differences between the diet as estimated by QFASA and as deduced from stomach contents. This study revealed that the longer term diet of porpoises in Dutch coastal waters consists both of coastal species (e.g. gobies, smelt and dragonet) and also pelagic, schooling species (e.g. mackerel and herring). The results also brought to dawn possible methodological problems in using QFASA for porpoise diet estimation, emphasizing the importance of applying different dietary analysis techniques when studying marine mammal diets and the need for controlled feeding experiments in order to improve the interpretation of dietary analysis results (Chapter 5).

    Besides new insights in the feeding ecology of porpoises, stable isotope analysis also elicited a non-food related conservation ecology issue. Distinct δ13C values in muscle of porpoises stranded in the Eastern Scheldt revealed that these porpoises foraged there for a longer period. This distinct δ13C signature of animals from the Eastern Scheldt was not observed in bone tissue, which suggests a relatively recent shift in habitat use rather than life-long residency of porpoises within the Eastern Scheldt. The high number of strandings within the Eastern Scheldt revealed a higher mortality rate compared to the Dutch coastal zone, indicating that along with other changes in the physical environment, the building of the storm surge barrier may play an important role in determining the residency of porpoises in the Eastern Scheldt, and that the area might act as an ecological trap for porpoises entering it. This is an example of the impact on marine species due to protection structures that emerge and respectively increase worldwide in response to the effects of global warming and climate change. It highlights that even semi-open structures, which are meant to ameliorate habitat loss, degradation and fragmentation, may still affect the abundance and distribution of migratory marine mammal species (Chapter 4).

    The analysis of stomach contents of white-beaked dolphins showed that their diet was dominated by Gadidae. All other prey species combined contributed little to the diet by weight. The two most important prey species based in weight were whiting and cod. In numbers, gobies were most common, but these contributed little to the diet by weight. The overall diet showed a lasting predominance of whiting and cod, without clear changes over time (35 years) or differences between sexes or size-classes of dolphins and revealed that white-beaked dolphins in the south-eastern North Sea are specialist feeders, with a strong preference for whiting and cod (Chapter 6).

    Stomach contents of juvenile white-beaked dolphins in our study revealed that at the age of about 1.5 years old, they had started feeding on solid food by taking a variety of small fish and invertebrate prey, mostly shrimp and squid. Immatures in our study, estimated to be 2-4 years old, still take small prey, including small gadoids, but also take larger gadoids. Calves apparently gradually learn to eat big fish by taking prey that is much smaller than those normally taken by their mothers. This study illustrates novel techniques for diet estimation to reconstruct sizes of shrimp and whiting from tail flaps and eye lenses, respectively (Chapter 7).

    Most dietary studies on porpoises and white-beaked dolphins are deduced from stomach contents. This thesis has demonstrated that using indirect methods for studying the feeding ecology of marine mammals is a valuable addition to the more direct approach using stomach contents. It supports the need for multi-method approaches because by using only one technique, key prey species in the predator-prey relation may be missed or underestimated. Future ecological and fishery impact assessment studies and management decisions for the conservation of porpoises and white-beaked dolphins should acknowledge a difference between their long- and short-term diet. Large improvement in the interpretation of the results from diet analyses can be established either by controlled feeding experiments with animals in captivity or by studies that help to understand the common principals in dietary analyses (e.g. digestion rates, turnover rates of tissues, tissue-dependent isotopic fractionation between predator and prey and lipid metabolism within the animal) and variation of these between species.

    Evaluation of local protein resources for growing pigs in Central Vietnam
    Nguyen Thi Hoa Ly, Ly - \ 2012
    Wageningen University. Promotor(en): Martin Verstegen; W.H. Hendriks, co-promotor(en): L.D. Ngoan. - S.l. : s.n. - ISBN 9789461732835 - 145
    diervoeding - varkens - eiwitten - groei - cassave - diëten - zoete aardappelen - vietnam - animal nutrition - pigs - proteins - growth - cassava - diets - sweet potatoes - vietnam

     The general objectives of the work presented here were to evaluate processing methods for the preservations of cassava leaves (CL) and sweet potato vines (SPV) for later feeding during feed shortages in Vietnam. In addition, the nutritional value (including hydrogen cyanide (HCN) contents) of stored and processed CL and SPV as ingredients in diets for pigs were studied to determine their optimal use.

    The impact of different levels of various carbohydrates added to CL on ensiling and chemical properties was investigated (study 1). Inclusion of rice bran or cassava root meal at 5 or 10% (fresh basis),produced good quality silage that can be stored for up to three months. Ensiling reduced the HCN content up to 80% compared to the content in fresh CL. Using ensiled or dry CL and SPV to replace 70%of the crude protein in a practical fish meal based diet commonly used in Vietnam, gave similar performance results and carcass traits of Large White×Mong Caipigs (study 2). However, increasing ensiled CL from variety KM94 from 0 to 20% (in DM) in diets caused a significant decrease in the average daily gain of pigs but resulted in a 9-18% reduction in feed cost (study 3). Studies into the ileal and total tract apparent digestibility of amino acids and crude protein of ensiled and dried CL and SPV showed that these feed ingredients have the potential to improve the supply of amino acids and protein to growing pigs when fed practical diets (study 4). The chemical analyses indicated CL to have a higher crude protein content than SPV and that ensiling slightly decreases the crude protein as well as the amino acids content. Ensiling however, resulted in a higher digestibility of dietary nutrients compared to drying. Thefirst and second limiting amino acids for ensiled and dried CL and SPV for growing pigs were methionine+cysteine and lysine. Mixing ensiled CL and SPV vines may provide additional benefits in terms of amino acid digestibility over feeding these ingredients alone to pigs. Supplementation of diets containing ensiled CL with methionine and lysine showed that the performance of growing pigs can be increased, as well as the economic benefits for farmers (study 5).

    The work presented shows that CL and SPV are economical alternatives for more traditionally protein source (e.g. fish meal, soybean meal) for pigs in Vietnam. Ensiling appears to be a practical solution to conserve sweet potato vines and cassava leaves and provide a solution for the rainy season when preservation by sun-drying is difficult.


    Effects of dietary changes on heat stress in broiler and Kampung chickens
    Syafwan, W. - \ 2012
    Wageningen University. Promotor(en): Martin Verstegen; Wouter Hendriks, co-promotor(en): Rene Kwakkel. - S.l. : s.n. - ISBN 9789461731326 - 199
    vleeskuikens - kippen - gevogeltevoeding - diervoeding - diëten - voer - warmtestress - voedingsgedrag - vleeskuikenresultaten - voedingsfysiologie - broilers - fowls - fowl feeding - animal nutrition - diets - feeds - heat stress - feeding behaviour - broiler performance - nutrition physiology

    Poultry meat production has increased drastically over the last 35 years. Most developing countries are in the tropics and often have high ambient temperatures. At high ambient temperatures, chickens exhibit a slower growth rate due to a reduced feed intake. In order to limit the reduction in feed intake, a feeding strategy should be applied which decreases the level of heat production and/or increases the possibilities for heat dissipation. Such a feeding strategy can be based on feed that gives less heat because of lower energy costs of digestion or provides fewer nutrients that lead to a high heat production. This thesis studied how birds subjected to chronic heat stress change feed intake of especially crude protein and total energy. In addition, a wet feeding strategy that might alleviate the adverse effects of heat stress on performance was applied. Chickens exposed to choice feeding responded similarly at normal and at high ambient temperatures. They composed from a choice of a control diet, an energy rich diet and a protein rich diet a diet with a higher energy (HE) content and a lower protein content compared to the standard control diet. At high temperatures, chickens will reduce feed intake because they want to avoid or reduce a high body temperature. When the chickens were fed a wet-HE diet, feed intake and BW gain were higher in broiler chickens compared with feeding a dry-HE diet. The most beneficial effects of a wet diet occurred with a high energy diet. The indigenous Kampung chickens have been acclimatized to a high ambient temperature and did not benefit from a wet diet.

    In the present study, temperature had a major effect on relative lengths and empty weights of gastrointestinal tract segments in broiler chickens on day 42. Relative lengths of most gastrointestinal tract segments were affected by diet formulation at day 21 and 42, but not relative empty weight. Control-fed birds had shorter relative lengths than HE-fed birds, suggesting that the higher BW gain of control-fed birds were not accompanied by a similar increase in length of the gastrointestinal tract. Wetting the diet did not increase empty weights of intestines both at days 21 and 42. In Kampung chickens, effects of diet formulation on gastrointestinal tract development disappeared when the birds grew older, suggesting that this type of bird adapts easily to changes in dietary nutrient content. A positive effect of the relative weight of the intestine of birds fed a wet diet was observed in Kampung chickens. In general, it seems that the Kampung chickens grow proportionally but broiler carcass is growing faster than its gastrointestinal tract in control- and wet-fed birds.

    Key words: Self-selection, temperature, wet diet, broiler, indigenous chicken

    Nitrogen efficiency of dairy cattle : from protein evaluation to ammonia emission
    Duinkerken, G. van - \ 2011
    Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Jan Dijkstra. - [S.l.] : S.n. - ISBN 9789085859925 - 179
    melkvee - melkkoeien - stikstofverliezen - ammoniakemissie - diëten - voer - rundveevoeding - diervoeding - eiwitbalans - landbouw en milieu - dairy cattle - dairy cows - nitrogen losses - ammonia emission - diets - feeds - cattle feeding - animal nutrition - protein balance - agriculture and environment

    Diet optimization contributes considerably to increased nitrogen efficiency of dairy cattle, resulting in reduced nitrogen losses. This thesis focuses on three themes: the potential advances in protein evaluation systems for ruminants, the relationship between dairy cow diet and ammonia emission and the opportunities to monitor ammonia emission from dairy cow barns by application of milk urea content as a practical indicator. Overall, the present work shows that farm management can be aimed at increased nitrogen efficiency of dairy cattle and reduced ammonia emission without compromising other sustainability objectives such as the integral ecological footprint, animal health and farm profitability.

    Je bent wat je eet : voeding en gezondheid
    Boekel, M.A.J.S. van; Everdingen, J. ; Graaf, C. de; Buiter, R. - \ 2011
    Cahiers bio-wetenschappen en maatschappij 30 (2011)2. - ISSN 0921-3457 - p. 1 - 84.
    voedingsanamnese - voedselkwaliteit - menselijk gedrag - humane voeding - gezondheid - gezondheidsvoedsel - diëten - functionele voedingsmiddelen - voeding en gezondheid - dietary history - food quality - human behaviour - human feeding - health - health foods - diets - functional foods - nutrition and health
    Hoe bepaal je wat gezonde voeding is? Als je dat al weet, hoe verspreid je die kennis? En waarom is het dat sommige voedingsmiddelen zo verdacht veel op medicijnen lijken?
    Het dieet van de Steenloper Arenaria interpres: een literatuuroverzicht
    Cremer, J.S.M. ; Smit, C.J. - \ 2009
    Texel : IMARES (Rapport / IMARES Wageningen UR C141/09) - 28
    arenaria (vogels) - scolopacidae - voedering - diëten - voedingsgedrag - nederland - voedingsecologie - waddenzee - westerschelde - arenaria (birds) - scolopacidae - feeding - diets - feeding behaviour - netherlands - feeding ecology - wadden sea - western scheldt
    Can diet composition affect behaviour in dogs? : food for thought
    Bosch, G. - \ 2009
    Wageningen University. Promotor(en): Wouter Hendriks; Martin Verstegen, co-promotor(en): Thomas van der Poel; Bonne Beerda. - [S.l. : S.n. - ISBN 9789085853565 - 144
    honden - hondenvoeding - diergedrag - vezels - diëten - voedselsamenstelling - dierfysiologie - dierenwelzijn - voedingsvezels - dogs - dog feeding - animal behaviour - fibres - diets - food composition - animal physiology - animal welfare - dietary fibres
    The consumption of food goes beyond the basic provision of energy and essential nutrients for the maintenance of physical health. Studies in rats, pigs, and human subjects have shown that behaviour and mood can be influenced by specific nutrients consumed. The research described in this thesis aimed to evaluate the impact of dietary composition on two physiological systems involved in the regulation of canine behaviour. In other studies it has been shown that physical activity of pigs can be influenced by dietary fibre type, likely through sustaining satiety after a meal. It appears that the fermentable fibres can stimulate several mechanisms involved in sustaining satiety including the stimulation of the secretion of satiety-related metabolites by the gastrointestinal tract. Furthermore, hunger has been found to influence anxiety in rats. The current study evaluated the potential impact of dietary fibre types for effects on satiety and behaviour in dogs. Two in vitro fermentation studies were conducted to evaluate the microbial fermentation activity in the canine gastrointestinal tract and to screen the fermentability of various fibrous ingredients. Based on these in vitro fermentability data, two diets were formulated expected to differ in fibre fermentability in vivo. The difference in fibre fermentability between diets was confirmed in an in vivo study by evaluation of fibre degradation and concentrations of faecal short-chain fatty acids. In this latter study, the secretion of satiety-related hormones was found not to differ between treatment groups. Feeding dogs a high-fermentable fibre diet did result in a lower motivation to eat 6 hours after their morning meal and a lower activity in their home-kennel compared to dogs fed a low-fermentable fibre diet. Treatment groups did not differ in their responses to short-lasting challenges in a test arena conducted 5 to 7 hours after their morning meal. The second dietary strategy investigated was the use of the essential amino acid tryptophan, the precursor of the neurotransmitter serotonin in the brain. It has been shown that dietary tryptophan supplementation reduces anxiety in rats and increases resilience in dealing with stress in pigs. To investigate if similar effects would occur in dogs, a study was designed and conducted in mildly anxious privately-owned dogs fed diets differing in tryptophan content. Dogs were fed the study diet for 8 weeks using a randomised double-blinded, placebo-controlled design. Intake of the tryptophan supplemented diet increased plasma tryptophan concentrations by 37.4% and its ratio with large neutral amino acids by 31.2% compared to the control diet but the data reported by owners did not show a significant change in the behavioural of the dogs over time that could be attributed to the specific dietary treatment. More controlled behavioural tests conducted on a subset of dogs in both dietary treatment groups failed to show a significant difference of supplementation of the diet with tryptophan. In conclusion, the present work has shown that dietary fibre type can have an impact on canine behaviour through feeding motivation. The measured satiety-related metabolites were not affected by dietary fibre type indicating that other mechanisms were involved in sustaining satiety. Dietary supplementation of tryptophan had no effect on the behaviour of privately-owned dogs.
    Nutritional analysis and intervention in the captive woolly monkey (Lagothric lagotricha)
    Ange-van Heugten, K.D. - \ 2008
    Wageningen University. Promotor(en): Martin Verstegen, co-promotor(en): P. Ferket. - [S.l.] : S.n. - ISBN 9789085049012 - 191
    apen - diervoeding - diergezondheid - dierziekten - diëten - voedingsstoffen - levensverwachting - bloedserum - bloedchemie - diabetes mellitus - hydrocortison - voedselsupplementen - dierentuinen - dieren in gevangenschap - voeding en gezondheid - monkeys - animal nutrition - animal health - animal diseases - diets - nutrients - life expectancy - blood serum - blood chemistry - diabetes mellitus - hydrocortisone - food supplements - zoological gardens - captive animals - nutrition and health
    Woolly monkeys (Lagothrix ssp.) are a threatened species in the wild and are extremely difficult to breed and successfully maintain in captivity. The majority of health complications in woolly monkeys (WM) may be of nutritional origin. The objectives of this thesis were to: 1) determine the current status of the captive WM, 2) isolate potential nutritional causes for primary disorders in captive WM, and 3) investigate the effects that diet nutrients have on WM serum chemistry and cortisol concentrations. Our studies showed that the number of captive WM have decreased by 11% in the past 16 years. The number of institutions holding WM decreased and the birth to death ratio is 0.65 compared to 1.26 for their close relative the spider monkey (SM) (Ateles spp.). Lack of genetic diversity in captive WM also may negatively influence their success. Serum chemistry from 30 WM housed at two zoos were similar to previously reported concentrations for howler (Aloutta sp.) and SM; however, serum glucose was above the baseline range compared to humans and SM. Fasting concentrations of glucose, insulin, fructosamine, glycated hemoglobin, circulating lipids and urinary glucose were within normal ranges in six WM with known hypertension problems compared to other monkeys and humans. Potential stressors, such as unnatural diet, can contribute to the low success of endangered primates via noted health abnormalities. Fecal and salivary cortisol concentrations in WM and SM, at multiple zoological institutions showed that zoos with the highest dietary total carbohydrates, total sugars, glucose and fruit content had the highest cortisol. Supplementation of WM and SM diets with inulin-type fructans numerically decreased fecal cortisol after 4 weeks of supplementation, primarily in SM. The lifespan and reproductive success of captive primates will improve if stressors and negative effects of nutrition on the health status can be reduced and dietary nutrients can be optimized.
    Extrusion processing : effects on dry canine diets
    Tran, Q.D. - \ 2008
    Wageningen University. Promotor(en): Martin Verstegen; Wouter Hendriks, co-promotor(en): Thomas van der Poel. - [S.l.] : S.n. - ISBN 9789085049036 - 108
    honden - hondenvoeding - droogvoer - diëten - uitpersing - drogen - eiwit - lysine - zetmeelkorrels - smakelijkheid - voedermiddelbewerking - dogs - dog feeding - dry feeds - diets - extrusion - drying - protein - lysine - starch granules - palatability - feed processing
    Keywords: Extrusion, Canine diet, Protein, Lysine, Starch gelatinization, Palatability, Drying.

    Extrusion cooking is a useful and economical tool for processing animal feed. This high temperature, short time processing technology causes chemical and physical changes that alter the nutritional and physical quality of the product. Effects of extrusion on the feed quality for other animals than pets have been well recognized. Our studies investigated to what extent extrusion and/or drying of a complete canine diet affects lysine reactivity, amino acids, fatty acids, starch gelatinization and physical parameters.
    In order to create a general view of dog food quality in practice, the physical and nutritional quality of commercial canine diets available in the Netherlands were examined. This study showed unveiled variation in lysine reactivity and starch gelatinization of commercial dry canine diets. A study was then carried out on the effects of extrusion on the physical and nutritional values of canine diets in a FIDO model. The extrusion conditions (temperatures in the range of 110 to 150ºC, 300 g/kg moisture) increased lysine reactivity, starch gelatinization and in-vitro starch digestibility. Protein digestibility and dispersibility were not affected by the extrusion conditions used. The increase in the extrusion temperature used (110 to 150ºC) decreased kibble durability but did not affect hardness. This study also concluded that optimisation of extrusion conditions during production of commercial canine diets should include the measurement of the reactive to total lysine ratio. Single ingredients of a complete canine diet did not respond in a similar way during extrusion: extrusion had no effects on animal ingredients (higher lysine contents) while extrusion could decrease (in barley) or increase (in rice) the reactive lysine content in vegetable ingredients (lower lysine content). Both reactive lysine content and ratios of reactive to total lysine of the mixture of all vegetable ingredients were hugely increased during extrusion. Finally, an additional study was carried out on the effects of drying on extruded canine diets. The results of this study showed that drying temperature (in the range of 120-160ºC) and drying time did not affect the quality of extruded canine diets in terms of amino acids and fatty acids levels while these drying temperatures reduced drying time from hours to minutes. Drying temperature only affected the reactive lysine content and, therefore, the ratio of reactive to total lysine of kibbles dried at a temperature of 200ºC. Drying temperature also affected a minority of fatty acids with fatty acid C18:3 n-3 being the most affected at a drying temperature of 200ºC.
    In conclusion, extrusion at temperatures in the range of 130-150ºC and at a moisture of 300 g/kg is a mild heat treatment with respect to protein quality for pet food production. Measurement of the ratio of reactive to total lysine should be included in optimisation of extrusion conditions during pet food production. Drying temperature in the range of 120-160ºC and drying time do not affect the amino acids and fatty acids level of extruded canine diets.

    Birch pollen allergy: molecular characterization and hypoallergenic products
    Schenk, M.F. - \ 2008
    Wageningen University. Promotor(en): Evert Jacobsen; Lynn Frewer, co-promotor(en): Rene Smulders; Luud Gilissen. - [S.l.] : S.n. - ISBN 9789085048732 - 192
    betula - allergieën - allergenen - appels - voedselallergieën - diëten - transgene planten - houding van consumenten - cultivars - plantenveredeling - selectie - ige - dna-sequencing - genetische variatie - hooikoorts - moleculaire veredeling - betula - allergies - allergens - apples - food allergies - diets - transgenic plants - consumer attitudes - cultivars - plant breeding - selection - ige - dna sequencing - genetic variation - pollen allergy - molecular breeding
    Allergic diseases, such as hay fever and food allergy, affect a substantial part of the population in westernized countries. Pollen of the European white birch (Betula pendula) is a considerable cause of hay fever (seasonal allergic rhinitis) in northern and central Europe. The major birch pollen allergen is Bet ν 1, which is the conventional allergen name for the birch pollen proteins of a large group of proteins otherwise known as PR-10 proteins. Individuals that suffer from birch pollen allergy are particularly prone to develop Oral Allergy Syndrome (OAS) due to the occurrence of an IgE-mediated cross-reaction between Bet ν 1 and PR-10 proteins in various plant foods. The high prevalence of apple allergy among hay fever sufferers is a good example of OAS. Allergic diseases can be severe for patients and have considerable medical and economical costs as well. Consequently, prevention of birch pollen allergy and OAS would contribute to an improvement of the quality of life of many patients. This thesis examines the feasibility of strategies that are directed towards development of hypoallergenic (= having a reduced allergenicity) birch trees or plant foods in order to alleviate Bet ν 1 [PR-10]- associated complaints.
    When the development of hypoallergenic products involves application of genetic modification (GM), societal concerns about this technology should be taken into account. The attitude towards hypoallergenic products developed by GM was examined in the survey that is described in Chapter 2. This study differentiated between patients and non-patients. Attitude towards GM was measured for two applications directed against hay fever (hypoallergenic birch and grass) and one application directed against food allergy (hypoallergenic apple). Attitude was described in terms of two constructs that were labelled as 'benefits' and 'rejection factors'. Hay fever sufferers perceived greater 'benefits' associated with application of GM to develop hypoallergenic birch trees as compared to non-sufferers. The perceived 'benefits' increased with a higher self-reported impact of hay fever on quality of life. No attitudinal differences were observed between sufferers and non-sufferers for the attitudinal construct 'rejection factors'. Furthermore, the impact of perceived 'benefits' on acceptance of GM was larger than the impact of 'rejection factors'.
    The perceptions of 'benefits' were further explored in Chapter 3. Here, the attitude towards hypoallergenic apples was examined in a survey in which consumers rate a set of apple profiles that varied in the breeding method that was applied during development (GM vs. traditional breeding), in pesticide usage, and in the degree of allergenicity. Acceptance of hypoallergenic apples was high among all consumers, also when GM was involved in their development. Acceptance of hypoallergenic products was higher among consumers with an apple allergy, presumably because they find a personal 'benefit' associated with these products. Novel GM products that are recognised as beneficial by some consumers may consequently experience an increased acceptance. However, both Chapter 2 and 3 indicated a clear consumer preference for
    traditional breeding over breeding by GM for the development of hypoallergenic birch trees or food products. Approaches which focus on traditional breeding should thus be explored first.
    Chapter 3 also evaluated appreciation of the hypoallergenic apple cultivar Santana, which was introduced in shops in a large-scale sales pilot labelled as 'suitable for individuals suffering from mild apple allergy' in 2006. A survey among consumers that bought the Santana measured the self-reported response to this apple. Almost half (42%) of the apple allergic consumers had no allergic reaction at all after eating the Santana. Most (96%) consumers who did experience an allergic reaction reported the symptoms as minor. The self-reported severity of the apple allergy, the occurrence of other fruit allergies, and age were associated with the occurrence of an allergic reaction to the Santana. Overall, the Santana was valued positively by the majority of apple allergic consumers, regardless of whether these consumers could eat the apple without experiencing an allergic reaction. Development of hypoallergenic foods such as Santana may therefore contribute to food allergy management, although variation among individual consumers in the allergic response to hypoallergenic products should be taken into account when developing and marketing such products.
    A prerequisite for designing strategies for selection and breeding of hypoallergenic birch trees is knowledge on diversity of Bet ν 1 genes and on allergenicity of the protein variants (=isoforms) that are encoded by these genes. Chapter 4 describes a study on the variation of Bet ν 1 isoforms in .the most common birch species in Europe, Betula pendula. PR-10 sequences from three B. pendula cultivars were amplified, cloned and sequenced. Forty-four unique PR-10 sequences were recovered from B. pendula and these were assigned to thirteen putative genes based on sequence identity and intron length. Information on gene transcription was inferred from a comparison with existing mRNA sequences and suggested that seven of these genes are transcribed in pollen. Bet ν 1 isoforms are known to vary in IgE-reactivity. The study in Chapter 4 showed that isoforms with high and low IgE-reactivity are encoded by different genes. Thus, one birch pollen grain has the genetic background to produce a mixture of isoforms with varying IgE-reactivity. The sequence of one of the isoforms with a high IgE-reactivity was present in all examined B. pendula trees. The search for hypoallergenic birch trees was, therefore, expanded to other Betula species.
    The selection of a representative set of species which cover variation among Betula species requires knowledge on phylogenetic relationships within the genus Betula. Chapter 5 describes a study on the reconstruction of the phylogeny of this genus using multilocus data from AFLP markers. The taxonomy of the genus Betula is complicated by the occurrence of parallel evolution of morphological traits, of polyploidisation events, and of extensive hybridisation among species. A large number of polymorphic AFLP markers (321 variable bands) were produced in 107 Betula accessions from 23 species and 11 hybrids. The analysis identified four distinct groups within the
    genus. These groups are partly in disagreement with the traditional, but disputed, division of the genus. The majority of the species and all hybrids fell within subgenus Betula and are thus closely related to B. pendula. Subgenus Chamaebetula and part of the Neurobetula species should be merged with subgenus Betula. Apart from subgenus Betula, the subgenera Betulenta, Betulaster, and the remaining part of Neurobetula formed distinct and well-supported groups and should thus be maintained. The results from the AFLP study are to a large extent congruent with results from previous studies that made use of molecular (sequence) data.
    The allergenic potency of Betula species other than B. pendula is described in Chapter 6 in which the PR-10 genes from eight birch species are cloned and sequenced. These species represent the various groups that were previously identified in the genus Betula. In total, 134 unique PR-10 sequences were recovered, including both sequences with a full open reading frame and pseudogenes. Sequences were attributed to putative genes, which could, in turn, be subdivided into seven subfamilies. Five subfamilies were common to all birch species. Q-TOF LC-MSE was applied to detect peptide fragments of Bet ν 1 that are unique for particular isoforms, in order to identify which PR-10 genes are expressed in pollen. The relative abundance of individual isoforms in the pollen proteome was also determined by Q-TOF LC-MSE. Each of the five examined birch species expressed a mixture of isoforms with at least 4-5 different isoforms. Both isoforms with a high and low IgE-reactivity were abundant in the Bet ν 1 mixture of B. pendula. The other birch species lacked Bet ν 1 isoforms that are similar to known isoforms with a low IgE-reactivity, but isoforms that are similar to known isoforms with a high IgE-reactivity were abundant in all species except B. lenta.
    In Chapter 7, the antigenic and allergenic profiles of pollen extracts from twenty-four different birch trees were determined by SDS-PAGE and Western blotting. Fifteen different Betula species were examined, covering all previously identified subgenera/groups in the genus Betula. The major birch allergen Bet ν 1 was an abundant protein in all examined pollen extracts. Immune-reactivity of the extracts was tested using a pool of sera that were obtained from birch pollen allergic patients. A strong 17 kDa band, representing Bet ν 1, was recognized by the serum pool in all pollen extracts. The degree of immune-reactivity correlated well with the total amount of Bet ν 1 in the extract, which varied from 44% to 61% of the total protein content. Pollen extracts from different birch trees varied in the total protein content, presumably the result of variation in pollen quality due to pollen rupture and varying hydration during the extraction. Bet ν 1 isoforms in the pollen of eleven Betula species were subsequently digested with trypsin and the resulting fragments were analyzed and quantified by Q-TOF LC-MSE. Peptides that contained amino acid residues that are associated with high IgE-reactivity were detected in all examined species, and were abundant as well. Differences between Betula species in the relative presence of these amino acid residues were small. As a consequence, differences in allergenicity between birch trees
    are probably far too small to have clinical relevance, implying that all examined Betula species will be highly allergenic.
    The research presented here did not identify any birch trees in which Bet ν 1 variants with a high IgE-reactivity are reduced in abundance or are absent. Development of hypoallergenic birch trees thus must rely on other approaches, such as selection or introduction of male sterility (trees that do not produce male catkins were observed during the study), or the application of RNAi to silence the Bet ν 1 genes in pollen. Also, the conducted research showed that acceptance of hypoallergenic GM products is quite high, particularly for allergic sufferers who were allergic to the product being modified. This supports the hypothesis that consumer attitude towards GM is partly driven by recognition of specific and personally relevant benefits. The hypoallergenic apple cultivar Santana, which was developed by selection and not by GM, was well received by allergic consumers, indicating that there is a market for hypoallergenic products.

    Energy partitioning in dairy cows : effects of lipogenic and glucogenic diets on energy balance, metabolites and reproduction variables in early lactation
    Knegsel, A.T.M. van - \ 2007
    Wageningen University. Promotor(en): Bas Kemp; Seerp Tamminga, co-promotor(en): Henry van den Brand; Jan Dijkstra. - [S.l.] : S.n. - ISBN 9789085047346 - 166
    melkkoeien - energiebalans - diëten - voer - voedingsstoffen - lipiden - glucose - stofwisselingsstoornissen - voortplanting - immuunsysteem - lactatie - dairy cows - energy balance - diets - feeds - nutrients - lipids - glucose - metabolic disorders - reproduction - immune system - lactation
    Keywords: dairy cows; dietary energy source; glucogenic nutrients; lipogenic nutrients; negative energy balance; metabolic disorders; reproduction, immune system Dairy cows experience a negative energy balance (NEB) in early lactation which results from high energy requirements for milk production accompanied by a limited energy intake. Nutrition has been indicated as an important factor in the incidence and severity of NEB and NEB–related metabolic and reproductive disorders, like ketosis and delayed resumption of ovarian activity. A metabolic effect of a NEB in dairy cows is suggested to be an unbalanced availability from glucogenic and lipogenic nutrients. The objective of this thesis was to study the effect of lipogenic and glucogenic diets on the energy balance (EB) and risk of metabolic and reproductive disorders in dairy cows in early lactation. The first study, a literature survey, illustrated that feeding extra glucogenic nutrients relative to lipogenic nutrients, decreased milk fat and seemed to decrease plasma non-esterified fatty acid (NEFA) and β-hydroxybutyrate (BHBA) concentrations. Since studies were scarce and mostly included a confounding effect of dietary energy source with energy intake, it was difficult to draw conclusions on the energy source effects on EB and fertility. Therefore, in the second study, 16 dairy cows were either fed a glucogenic or a lipogenic diet. Diets were isocaloric and equal in intestional digestible protein. Energy balance was determined in climate-respiration chambers from week 2 until week 9 of lactation. The glucogenic diet decreased milk fat yield and milk energy and tended to decrease body fat mobilisation compared with the lipogenic diet. The objective of the third study was to study the effect of dietary energy source on EB, metabolites and some reproduction variables. Dairy cows (n=111) were fed glucogenic, lipogenic or mixed diet from week -3 until week 9 relative to calving. Multiparous cows fed the glucogenic diet had lower milk fat yield, higher calculated EB, and lower plasma NEFA, BHBA and liver tri-acyl glyceride concentration and tended to have less days postpartum till first ovulation. Additionally, in the third study, the presence of natural antibodies (NAb) in plasma and milk of individual dairy cows was determined. Relations were detected between NAb and EB and plasma metabolites, suggesting that alterations in immune competence peripartum are reflected in the humoral part of the innate immune system. In conclusion, increasing the glucogenic nutrient availability improved the EB and had potential to reduce the risk of metabolic disorders and to improve reproductive performance in dairy cows.
    Wet and coarse diets in broiler nutrition: development of the GI tract and performance
    Khoa, M.A. - \ 2007
    Wageningen University. Promotor(en): Martin Verstegen, co-promotor(en): Thomas van der Poel; Rene Kwakkel. - [S.l.] : S.n. - ISBN 9789085046820 - 141
    vleeskuikens - diëten - gevogeltevoeding - brijvoedering - vaste voeding - spijsverteringskanaal - biologische ontwikkeling - vleeskuikenresultaten - diervoeding - broilers - diets - fowl feeding - wet feeding - solid feeding - digestive tract - biological development - broiler performance - animal nutrition
    Diet structure and conformation during the starter phase play an important role in the functional development of the gastro-intestinal (GI) tract of broiler chicken, in particular the foregut segment.\u00a0Feed structure has a significant effect on the development of the foregut segments in broiler chickens. The development of the gastro-intestinal tract in chickens is aimed to adapt and to develop in line with the body in order to meet animal's demands for production traits and it should avoid the GI tract malfunction and improper GI tract development. These can be done by changing (alternating) feed properties and in feeding strategies during the starter phase. Chicken's diet components may be treated in order to enable the crop, theproventriculus- gizzard system to function optimally. Thus they will optimize feed digestion and utilisation. Therefore, the focus of this thesis was: 1)Tounderstand the impact of changes in feed properties like technological treatments on broiler's performance. The technological changes in feed were made to induce differences in structure (particle sizes) and appearance (solid or liquid diets) of the feed and how this feed during the starter phase (0 - 3 weeks of age) influences the development and functioning of the foregut (crop andproventriculus); 2) To develop a feeding regime which optimizes foregut development and function of the foregut segment during starter phase and to see if there is a lasting effect on the following period, in other words, whether there is a carry over effect on performance of broilers during the grower phase. It has been shown that the starter period is critical for GI tract development. Feeding coarse diets during the starter phase improves the functional development of theproventriculus-gizzard system. Wet feeding improves feed intake and, as a consequence, broiler performance. Feeding a wet and coarsely ground diet provides a large improvement in feed intake, feed conversion and body weight gain, showing the most pronounced effects during the starter phase of broiler's life.
    Odor from pig production: its relation to diet
    Dinh Phung, P.D. Le - \ 2006
    Wageningen University. Promotor(en): Martin Verstegen, co-promotor(en): Andre Aarnink; Nico Ogink. - [S.l.] : S.n. - ISBN 9789085045281 - 206
    varkens - mest - geurstoffen - stankemissie - varkenshouderij - varkensvoeding - voer - diëten - diervoeding - pigs - manures - odours - odour emission - pig farming - pig feeding - feeds - diets - animal nutrition
    Keywords.Odor, Pigs, Diet, Manure, Protein, Amino Acids, Fermentable carbohydrates

    Odor from pig manure creates a serious nuisance for people living near pig farms. Odor is a mixture of various compounds, of which 4 groups may be the major contributors: sulfurous compounds, indolic and phenolic compounds, volatile fatty acids, and ammonia and volatile amines. Odor is evaluated both sensorily (odor concentration, intensity and hedonic tone) and chemically. Odor originates mainly from microbial conversion of protein (CP) and fermentable carbohydrates (FC) in the intestine of pigs and by microbial conversion of urinary and fecal compounds in the manure. There is increasing interest in reducing odor at the source by altering diets. In four different experiments, dietary factors were investigated for effects on odor emission, odor intensity and hedonic tone and ammonia emission from growing and finishing pigs' manure. Lowering dietary CP level from 18 to 12% and supplementing essential amino acids (AA) reduced odor emission by 80%.Supplementing sulfur-containing AA at a level of three times the animal requirement increased odor emission by 723%.Diets with low levels of CP and sulfur-containing AA increased odor hedonic tone (producing less unpleasant odor).Dietary CP and FC had an interactive effect on odor emission. At a high dietary CP level, increased FC level decreased odor emission, while at a low CP level, increased FC level increased odor emission from pig manure. Ammonia emission from pig manure was reduced by a low dietary CP level and supplementing most essential AA and by increasing dietary FC. The correlation between odor emission and ammonia emission was low and deemed non-significant. Dietary approaches which are efficient in reducing ammonia emission may have no or even opposite impacts on odor reduction. From our studies, we can conclude that sulfurous compounds were the most important odorous compounds causing odor nuisance. When minimal diet requirements are met, dietary alterations did not affect animal performance. Altering multiple dietary factors and evaluating their correlations affecting odor production and emission is more efficient in odor nuisance reduction than altering a single dietary factor. Dietary alterations are shown to be very effective in reducing odor nuisance from pig manure.
    Postprandial fate of amino acids: adaptation to molecular forms
    Nolles, J.A. - \ 2006
    Wageningen University. Promotor(en): Martin Verstegen, co-promotor(en): Victor Schreurs. - S.l. : S.n. - ISBN 9789085043423 - 120
    ratten - diermodellen - aminozuren - diëten - diervoeding - oxidatie - metabolisme - adaptatie - darmabsorptie - voedingsfysiologie - rats - animal models - amino acids - diets - animal nutrition - oxidation - metabolism - adaptation - intestinal absorption - nutrition physiology

    During the postprandial phase dietary proteins are digested to peptides and amino acids and absorbed. Once absorbed the peptides are further hydrolyzed to amino acids and transported to the tissues. These amino acids are largely incorporated into body proteins. Not all amino acids are, however, incorporated into body proteins part of these amino acids are oxidized, and can, thus, no longer be utilized to support protein metabolism in the body. The objective of this thesis was to increase the understanding of those processes that determine the utilization efficiency of dietary proteins. The studies described in this thesis, focused on the appearance rate of dietary amino acids in the free amino acid pool of the body. The rate of appearance of dietary amino acids in this pool has been shown to modulate the postprandial oxidation of amino acids and thereby also their utilization efficiency for physiological purposes. As a consequence postprandial oxidative losses influence the nutritional protein status of the body. This thesis aimed to elucidate whether the body is able to cope with diets in which the amino acid appearance rate is high and what mechanisms are involved in this process.

    First an effort was made to establish the metabolic consequences of amino acid sources with a high appearance rate in a rat and a human model. Postprandial oxidation of free or protein derived [1-13C]- leucine was determined in a [13CO2]-breath test, using both a diet consisting of only free amino acids including [1-13C]-leucine and a diet consisting of proteins in which [1-13C]-leucine was incorporated, and 1:1 mixtures of both diets. In those mixed diets either the protein part or the free amino acid part was labeled. The postprandial oxidative losses of dietary leucine after 5 days being fed these diets (short-term adaptation) appeared to be significantly higher for the free amino acid diet compared to the protein diet. These differences between dietary free amino acids and dietary protein persisted in the mixed diets, as measured by the [13CO2] breath-test. It was concluded that amino acids derived either from a free amino acid or a protein diet, were handled independently even when ingested simultaneously during the same meal. Results obtained in rats were comparable to the results obtained in humans.

    The differences in oxidation between a free amino acid and a protein diet had largely disappeared after long-term adaptation (after 26 to 30 days on the diet). An adaptive decrease in the oxidation of free amino acids was observed. In the second study it was examined to which extent increasing levels of methionine supplements in a diet (50, 100 or 200% methionine supplement relative to casein) were retained in body protein. This was thus far not clear since a higher appearance rate in the free pool has been reported to have a negative influence on the efficiency of utilization of amino acids from the diet. Moreover, only specific patterns of amino acids are supposed to be deposited in body protein. Higher dietary methionine levels resulted in higher postprandial oxidative losses of methionine. The groups, which were fed the diets with the highest methionine levels, showed the lowest methionine retention as part of intake but the highest retention in absolute terms. After long term adaptation, however, to the free amino acid diets, methionine retention was increased in all groups. It was concluded that postprandial retention of dietary amino acids is, at least in part, driven by the amino acid composition of the diet.

    In third study it was examined whether the postprandial fate of different dietary amino acid was regulated by hormonal responses to the diet. It has been observed that the differences in oxidative losses between diets consisting of free amino acids or protein were not mediated by the combined action of insulin, glucagon, corticosterone and GH. Hence, postprandial catabolism of amino acids is probably regulated by other mechanisms. As stated above, the amino acid appearance rate plays a crucial role in determining the postprandial utilization of amino acids. In the fourth study it was, therefore, investigated, whether the amino acid absorption rate can adapt to dietary free amino acids. Rats were kept on a free amino acid diet for 0 (nonadapted), 5, or 26 to 30 days (long-term adaptation). The methionine absorption of long-term adapted rats was lower than that of the non-adapted rats. It was concluded that the absorption of amino acid by the intestine plays a crucial role in minimizing the postprandial oxidative losses.

    Consequences of different strategies of free amino acid supplementation to dietary proteins for physiological utillization
    Gas, M. - \ 2006
    Wageningen University. Promotor(en): Martin Verstegen, co-promotor(en): Victor Schreurs; J. Bujko. - s.n. : S.n. - ISBN 9789085043355 - 150
    ratten - diermodellen - diëten - voer - vrije aminozuren - voedersupplementen - voedingseiwit - katabolisme - oxidatie - voedingsfysiologie - rats - animal models - diets - feeds - free amino acids - feed supplements - dietary protein - catabolism - oxidation - nutrition physiology
    The efficiency of using free amino acids (AAs) as dietary constituent is sometimes lower than that of AAs derived from intact protein. The aim of the project was to evaluate dietary management conditions, which can determine the efficiency of utilization of crystalline AAs in animal diets or in clinical nutrition. The studies in this thesis were focused mainly on differences in short-term catabolism between protein bound and free AAs during the post prandial phase of a meal. The stable isotope technique was used in model studies with laboratory Wistar (WU) rats. In different experiments, so-called [ 13 CO 2 ]-breath test studies were used to compare the metabolic fate of free and protein-bound [1- 13 C]-labeled AAs in a meal in various nutritional situations. The influence of free AA supplementation strategies on weight gain development was also studied. Moreover, protein and fat content in the liver and carcass were analysed.

    The results of the present study confirm literature that showed a higher post prandial catabolic losses of the tracer when dietary protein is replaced with crystalline AAs. In some, but not all situations a lower weight gain was observed for growing animals. Our results showed that short-term catabolic losses of endogenous leucine were modulated by exogenous AA supply. It increased or decreased depending on the adequacy of the dietary supply.

    The common practice for free AA supplementation is to mix it with the deficient protein. In our study we showed that during the post prandial period the best utilization of methionine deficient protein did not occur when methionine supplement was given simultaneously with methionine deficient meal. The best utilisation occurred when there was a delay between the supply of deficient meal and free methionine. Therefore, introducing time interval of free amino acid supplementation to poor quality protein should be considered as a factor with potential to improve physiological utilization of dietary amino acids.A 1h time interval for free methionine supplementation influenced the weight gain, but differently depending on the protein level. Animals fed very deficient protein diet (5%) showed higher weight gain when supplementation of the deficient free methionine was provided with a 1h delay (1h interval). With protein deficient diets and less than 7.5 % protein we found fatty livers in our experiment. We concluded that post prandial AA oxidation influences the post absorptive AA catabolism. This does not always mean effect on growth. For growth in rats lysine deficiency is most limiting but it seems that even a 34% methionine deficiency below the NRC recommendation did not limit growth. We found that methionine deficiency influenced fat metabolism and from the literature we concluded that the mechanism probably works via choline and carnitin
    Nutrition Communication in Dutch General practice: integration of the patients' perspective and the family doctors' perspective
    Dillen, S.M.E. van - \ 2005
    Wageningen University. Promotor(en): Gerrit Jan Hiddink; Cees van Woerkum, co-promotor(en): Maria Koelen. - Wageningen : Grafisch Service Centrum - ISBN 9789085042488 - 180
    gezondheidsbevordering - gezondheidseducatie - communicatie - huisartsen - patiënten - ziekten - hart- en vaatziekten - suikerziekte - nederland - voedingseducatie - voedingsinformatie - diëten - health promotion - health education - communication - general practitioners - patients - diseases - cardiovascular diseases - nutrition education - nutrition information - diets - diabetes - netherlands
    A sound nutrition advice is important for patients with coronary heart disease, diabetes and obesity. The family doctor has high potential to promote nutrition to their patients through its broad reach, including the hard-to-reach low socio-economic class. Unfortunately, in daily practice of most family doctors, this nutrition communication is not optimal. Therefore, a combination of qualitative and quantitative studies among patients and family doctors was performed in order to explore and assess their communicative characteristics regarding nutrition communication.

    In our literature review, we searched for studies about the occurrence, the patients' perspective and the family doctors' perspective regarding nutrition communication in general practice. It can be concluded that results about the occurrence of nutrition communication in general practice differed widely. Moreover, patients' perceptions regarding nutrition communication through family doctors appeared to be positive. Family doctors' perceptions were positive too, but they also experienced several barriers, such as lack of time and patient non-compliance.

    To explore and assess the patients' perspective, we used focus groups, in-depth interviews and face-to-face interview-assisted questionnaires. A discrepancy between perceived relevance and information needs regarding food topics was discovered. Patients' perceptions regarding nutrition communication through family doctors were positive. Whereas patients had difficulties with estimating their nutrition behaviour, nutrition awareness is important as a first step in behavioural change. With our hypothetical model, we were able to unravel the concept of nutrition awareness. Individual variables were more prominent than environmental variables. In addition, gender and age added to our model. Total explained variance appeared to be 54%.

    In order to explore and assess the family doctors' perspective, we used focus groups and questionnaires. These studies showed that family doctors' were positive about nutrition communication towards their patients. However, they did not always feel capable to communicate about overweight. Moreover, family doctors used a combination of nutrition communication styles, namely informational, reference, motivational, confrontational and holistic nutrition communication styles. Our hypothetical model was tested for each nutrition communication style and showed explained variances up to 57%. Individual variables were the best predictors and socio-demographic variables did not add to the models. It is recommended that family doctors become convinced that patients prefer them for nutrition communication. Raising nutrition awareness among patients is necessary. Finally, we advise that family doctors realise that they can apply different nutrition communication styles.
    Diet composition and gut integrity in weaned piglets
    Spreeuwenberg, M.A.M. - \ 2002
    Wageningen University. Promotor(en): M.W.A. Verstegen; A.C. Beynen. - S.l. : S.n. - ISBN 9789058087386 - 176
    biggen - spenen - diervoeding - diëten - biggenvoeding - voer - samenstelling - spijsverteringsstoornissen - morfologie - fysiologische functies - ontsteking - piglets - weaning - animal nutrition - diets - piglet feeding - feeds - composition - digestive disorders - morphology - physiological functions - inflammation

    This thesis deals with the effects of dietary modulation of protein and carbohydrates under controlled energy intake on small intestinal integrity in weaned piglets. Small intestinal integrity is assessed on the basis of indicators regarding morphology (villus length, crypt depth), functionality (enzyme secretion and permeability across the gut wall) and inflammation (cell differentiation molecules on T cell lymphocytes and haptoglobin levels in blood plasma). The piglets were offered a predetermined maximum amount of feed in order to prevent entanglement between the effect of feed intake level and the effect of diet composition itself on small intestinal integrity. The effectiveness of protein versus lactose was investigated by changing the ratio of protein to lactose in the diet. Results indicated that lactose seemed more limiting than protein for epithelial cells in contributing to mucosal integrity during the first days after weaning. Therefore the specificity of lactose as carbohydrate source was investigated by feeding the piglets either glucose, lactose or native starch. However, those carbohydrate sources did not differentially affect mucosal integrity. Furthermore, changing protein digestibility or predigestion of protein did not affect mucosal integrity. Across diets, degeneration of the small intestine occurred already after one day postweaning and seemed more pronounced in the proximal small intestine, regeneration during the second week postweaning seemed more pronounced in the mid small intestine. The association between measurements regarding faeces consistency and small intestinal morphology was poor. It was concluded that the effect of the weaning induced low energy intake is in general more pronounced than the effect of diet composition on small intestinal integrity.

    Heat stress and diet utilization in male turkeys : the role of dietary energy and amino acids
    Veldkamp, T. - \ 2002
    Wageningen University. Promotor(en): M.W.A. Verstegen; R.P. Kwakkel; P.R. Ferket. - S.l. : S.n. - ISBN 9789058087324 - 176
    kalkoenen - mannelijke dieren - warmtestress - diëten - voer - aminozuren - energiegehalte - voedingsstoffenopname (mens en dier) - mestresultaten - kalkoenvoeding - diervoeding - turkeys - male animals - heat stress - diets - feeds - amino acids - energy content - nutrient intake - fattening performance - turkey feeding - animal nutrition

    Keywords: turkeys, heat stress, energy, amino acids.

    The commercial turkey industry has changed during the last two or three decades from one that marketed predominantly fresh whole dressed turkeys to one that now markets a large variety of mostly further processed products. Turkey breast meat is the most economically important part that is further processed. The turkey industry improved breast meat yield considerably by selective breeding, and advancements in management and feeding programs. Because breast meat yield is highly correlated with body weight, fast growing strains have been developed, but these strains are more sensitive to high ambient temperatures than earlier strains. This dissertation presents information on how male turkeys deal with chronic heat stress and how dietary amino acid and energy levels may alleviate the adverse effects of heat stress. Turkeys subjected to high ambient temperature will reduce their feed and associated nutrient intake because they need less energy for maintaining body temperature. A beneficial effect of including 10% extra dietary lysine, methionine, and threonine to diets that contained already high amino acid contents relative to NRC (1994), was not observed. Higher arginine to lysine ratios (1.25 vs. 1.00) only improved performance of turkeys when dietary lysine contents were marginal. Different electrolyte balances (164 to 254 meq/kg) did not modulate the effect of dietary arginine to lysine ratios. In an experiment with iso-caloric diets and different levels of dietary lysine (75, 90, 105, and 120% of NRC (1994) recommendations), the lysine requirement for optimum performance was determined to be the same for turkeys raised in either high or low ambient temperature when dietary energy contents met the requirement. In the last experiment, an evaluation was made of the response of male turkeys that were fed different dietary energy contents (NRC (1994) recommendations and ± 10%) and relatively high dietary lysine concentrations (105 and 120% of NRC (1994) recommendations) at high and low ambient temperature. The effect of extra dietary energy in the form of soybean oil had a more pronounced effect on performance at low than at high ambient temperature. High-energy diets resulted in lower breast meat yields.

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