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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Local dornase alfa treatment reduces NETs-induced airway obstruction during severe RSV infection
Cortjens, Bart ; Jong, Rineke de; Bonsing, Judith G. ; Woensel, Job B.M. Van; Antonis, Adriaan F.G. ; Bem, Reinout A. - \ 2018
Thorax 73 (2018)6. - ISSN 0040-6376 - p. 578 - 580.
infection control - innate immunity - neutrophil biology - paediatric lung disaese - respiratory infection - viral infection

Respiratory syncytial virus (RSV) infection is characterised by airway obstruction with mucus plugs, containing DNA networks in the form of neutrophil extracellular traps (NETs). We investigated the effect of dornase alfa on histopathological NETs-induced airway obstruction and viral load in an age-relevant calf model of severe bovine RSV disease. As compared with the control animals, dornase alfa treatment resulted in a strong reduction of NETs-induced airway obstruction. Viral load in the lower respiratory tract was not different between the two groups. We conclude that NETs form a relevant target for treatment of airway obstruction in severe RSV disease.

Effects of a commercial broiler enrichment programme with or without natural light on behaviour and other welfare indicators
Jong, I.C. de; Gunnink, H. - \ 2018
Animal (2018). - ISSN 1751-7311 - 8 p.
activity - bales - chickens - exploration - perches

Commercial broiler production systems based on market initiatives to improve animal welfare beyond minimum legal requirements have emerged in several European countries. A common factor in the ‘higher welfare’ indoor systems is the application of environmental enrichment, with or without natural light, to promote locomotor activity and natural behaviours of the broiler chickens. In the current study, we evaluated the effects of a commercial enrichment programme for fast-growing indoor-housed broiler chickens, with or without natural light entering the broiler house. Enrichment materials were selected in relation to perceived minimal hygiene risk and ease of cleaning in between production cycles. Selected enrichments were a combination of wood shavings bales (1.5 bale/1000 chickens), round metal perches (2.7 m/1000 chickens) and metal chains as pecking objects (1/1000 chickens). Three treatments were studied: control (C) without enrichment and natural light, enriched (E) with enrichments as previously defined but without natural light and enriched plus natural light (EL) with enrichments as previously defined and natural light entrance. The experiment was carried out during five subsequent production cycles on one commercial broiler farm with three identical houses. EL could only be assigned to the middle house that was equipped with roof windows (light entrance area: 3% of floor space). C and E were in the two outer houses (alternated in between production cycles). Behaviour was observed during daytime at days 25 and 39 of age by scan sampling. Lameness, footpad dermatitis, hock burn, cleanliness and injuries were scored at the same ages, in addition to the response of the chickens to a novel object. Results showed that the treatments only affected broiler behaviour. E flocks showed significantly more resting as compared with EL and C. EL flocks showed significantly more walking, exploration and foraging behaviour as compared with E and C. Thus, broiler activity was highest in the EL treatment and lowest in the E treatment, with the C treatment in between. No treatment effects were found on the other welfare indicators and only a few tendencies for treatment effects were found for the novel object test, with E birds tending to be more reluctant to approach the object as compared with EL and C birds. We concluded that providing environmental enrichment and natural light-stimulated activity and natural behaviours in broiler chickens, whereas providing enrichment only seemed to have the opposite effect as compared with control flocks without enrichment.

Effects of physicochemical characteristics of feed ingredients on the apparent total tract digestibility of energy, DM, and nutrients by growing pigs
Navarro, Diego M.D.L. ; Bruininx, Erik M.A.M. ; Jong, Lineke de; Stein, Hans H. - \ 2018
Journal of Animal Science 96 (2018)6. - ISSN 0021-8812 - p. 2265 - 2277.
Correlation - Digestibility - Energy - Physicochemical characteristics - Pigs - Total dietary fiber

Effects of physicochemical characteristics of feed ingredients on DE and ME and apparent total tract digestibility (ATTD) of GE, DM, and nutrients were determined in growing pigs using ingredients with different ratios between insoluble dietary fiber (IDF) and soluble dietary fiber (SDF). Eighty growing barrows (BW: 48.41 ± 1.50 kg) were allotted to a randomized complete block design with 10 diets and eight replicate pigs per diet. Dietary treatments included a corn-based diet, a wheat-based diet, a corn–soybean meal (SBM) diet, and seven diets based on a mixture of the corn–SBM diet and canola meal, distillers dried grains with solubles (DDGS), corn germ meal (CGM), copra expellers, sugar beet pulp (SBP), synthetic cellulose, or pectin. Values for the ATTD of DM and nutrients were also compared with the in vitro digestibility of GE, DM, and nutrients. Results indicated that the ATTD of GE was greater (P < 0.05) in wheat than in canola meal, DDGS, CGM, copra expellers, SBP, and synthetic cellulose, but not different from corn, SBM, or pectin. SBM had greater (P < 0.05) DE and ME (DM basis) compared with all other ingredients. The concentration of ME (DM basis) was greater (P < 0.05) in wheat than in canola meal, DDGS, CGM, copra expellers, SBP, synthetic cellulose, and pectin, but not different from corn. Stronger correlations between total dietary fiber (TDF) and DE and ME than between ADF or NDF and DE and ME were observed, indicating that TDF can be used to more accurately predict DE and ME than values for NDF or ADF. The DE, ME, and the ATTD of DM in ingredients were positively correlated (P < 0.05) with in vitro ATTD of DM, indicating that the in vitro procedure may be used to estimate DE and ME in feed ingredients. Swelling and water-binding capacity were positively correlated (P < 0.05) with the ATTD of IDF, TDF, non-starch polysaccharides (NSP), and insoluble NSP, and viscosity was positively correlated (P < 0.05) with the ATTD of NDF, IDF, and insoluble NSP, indicating that some physical characteristics may influence digestibility of fiber. However, physical characteristics of feed ingredients were not correlated with the concentration of DE and ME, which indicates that these parameters do not influence in vivo energy digestibility in feed ingredients. It is concluded that the DE and ME in feed ingredients may be predicted from some chemical constituents and from in vitro digestibility of DM, but not from physical characteristics.

Reducing damping-off problems in eggplant (Solanum melongena L.) : A participatory testing of nursery management in Bangladesh
Nahar, Naznin ; Islam, Md Rashidul ; Uddin, Mohammad Mahir ; Jong, Peter de; Struik, Paul C. ; Stomph, Tjeerd Jan - \ 2018
Crop Protection 112 (2018). - ISSN 0261-2194 - p. 177 - 186.
Damping-off - Healthy seedlings - Integrated pest management - Seed treatment - Soil treatment - Source of pathogens

Eggplant seedling production in homestead nurseries of farmers in Jamalpur (Bangladesh) is greatly compromised by damping-off. Therefore, farmers often do not have enough seedlings to transplant. Effective treatments of soil and seed to reduce disease pressure in the nurseries are available but little is known on the relative contributions of soil-borne and seed-borne pathogens to damping-off and on how nursery management can integrate management options under farmers’ conditions. A 2-year nursery study was conducted in consecutive seasons, jointly with farmers and using farmers’ preserved seed and farmers’ nurseries subject to damping-off problems. Year 1 involved a single nursery, Year 2 nine nurseries. The following treatments were tested: Trichoderma harzianum as soil amendment combined with seed treatment using either hot water or Carbendazim and farmers’ conventional practice: curative spraying after appearance of damping-off. In Year 1, a control (no intervention) treatment was also included. Emergence of seedlings, incidence of damping-off, seedling performance variables and farmers’ appreciation of seedling vigour were recorded. Soil treatment with T. harzianum combined with seed treatment with hot water increased seedling emergence and produced 25–64 percentage points more healthy seedlings than farmers’ conventional practice. This combined treatment also improved seedling performance (height, root length, lateral root development), and reduced stem girdling, a symptom associated with disease infection of transplants. To determine the contributions of nursery soil and farmers’ seed to damping-off, blotter and in vitro studies in the laboratory and tray studies in a screen house were performed. Soil proved to be the major pathogen source and treating nursery soil with T. harzianum had the largest positive effect on seedling performance, both reducing damping-off and enhancing seedling growth.

Van plaatsingsruimte naar bemestingsproducten : de sociale inkleuring van samenwerking in de mestmarkt
Buurma, Jan ; Jong, Daniël de - \ 2018
Wageningen : Wageningen Economic Research (Wageningen Economic Research rapport 2018-028) - ISBN 9789463437783 - 41
Dit rapport beschrijft een inhoudsanalyse - wie zegt wat, tegen wie, waarom en hoe? - van 100 artikelen uit Boerderij Vandaag over de mestmarkt en de akkerbouw uit de periode 2005-2016. De artikelen over de samenwerking tussen akkerbouw en veehouderij zijn beschreven als ware het een theatervoorstelling waarin de stakeholders elkaar bestookten met beelden en tegenbeelden. De theatervoorstelling laat een geleidelijke verschuiving zien van ‘kopen van plaatsingsruimte’ naar ‘leveren van bemestingsproducten’. Het rapport wordt afgesloten met aanbevelingen voor verdere kennisontwikkeling rond bodemverbetering en nieuwe opties voor samenwerking tussen akkerbouw en veehouderij.
Introgressive Hybridization in Potato Revealed by Novel Cytogenetic and Genomic Technologies
Gaiero, Paola ; Speranza, Pablo ; Jong, Hans de - \ 2018
American Journal of Potato Research (2018). - ISSN 1099-209X - 15 p.
Comparative genomics - Introgression - Potato wild relatives - Pre-breeding
Potato is the third most important food crop in the world and is crucial to ensure food security. However, increasing biotic and abiotic stresses jeopardize its stable production. Fortunately, breeders count on a rich pool of wild relatives that provide sources for disease resistance and tolerance to environmental stresses. To use such traits effectively, breeders require tools that facilitate exploration and exploitation of the genetic diversity of potato wild relatives. Introgression programs to incorporate such alien chromatin into the crop have so far relied on cytogenetic and genetic studies to tap desired traits from these wild resources. The available genetic and cytogenetic tools, supplemented with more recent genomic technologies, can assist in the use of potato relatives in pre-breeding. This information can also facilitate cisgenesis and genome editing to improve potato cultivars. Despite the abundant and rapidly growing genomic information of potato, that of its wild relatives is still limited.
Fruitteelt 4.0 met drones en zelfrijdende machines
Jong, Peter Frans de - \ 2018

Welke nieuwe technologieën zijn bruikbaar in de fruitteelt?

Incident vermeerdering leidt niet tot extra uitval
Jong, I.C. de; Riel, J.W. van - \ 2018
De Pluimveehouderij (2018). - ISSN 0166-8250 - p. 28 - 29.
Bij het optimaliseren van de vleeskuikenketen speelt de vermeerderingssector een belangrijke rol. Wageningen Livestock Research onderzocht de gevolgen van een productiedaling in vermeerderingskoppels op de eerste weeks uitval van de vleeskuikenkoppels en vond géén directe correlatie.
Urban Climate Adaptation : Nijmegen, the EU green capital 2018
Timmermans, W. ; Jong, F. de; Ginkel, Maarten van; Bruijn, Daphne de; Harsema, H. - \ 2018
INNOVA Ezine (2018)1-2018.
The contribution of digestible and metabolizable energy from high-fiber dietary ingredients is not affected by inclusion rate in mixed diets fed to growing pigs
Navarro, D.M.D.L. ; Bruininx, E.M.A.M. ; Jong, L. de; Stein, H.H. - \ 2018
Journal of Animal Science 96 (2018)5. - ISSN 0021-8812 - p. 1860 - 1868.
Digestibility - Energy - Fiber - Inclusion rate - Passage rate - Pigs

Effects of inclusion rate of fiber-rich ingredients on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of GE and on the concentration of DE and ME in mixed diets fed to growing pigs were determined. The hypothesis was that increasing the inclusion rate of fiber decreases digestibility of GE, and thus, the contribution of DE and ME from hindgut fermentation because greater concentrations may reduce the ability of microbes to ferment fiber. Twenty ileal-cannulated pigs (BW: 30.64 ± 2.09 kg) were allotted to a replicated 10 × 4 incomplete Latin Square design with 10 diets and four 26-d periods. There were 2 pigs per diet in each period for a total of 8 replications per diet. A basal diet based on corn and soybean meal (SBM) and a corn-SBM diet with 30% corn starch were formulated. Six additional diets were formulated by replacing 15% or 30% corn starch by 15% or 30% corn germ meal, sugar beet pulp, or wheat middlings, and 2 diets were formulated by including 15% or 30% canola meal in a diet containing corn, SBM, and 30% corn starch. Effects of adding 15% or 30% of each fiber source to experimental diets were analyzed using orthogonal contrasts and t-tests were used to compare inclusion rates within each ingredient. The AID and ATTD of GE and concentration of DE and ME in diets decreased (P < 0.05) with the addition of 15% or 30% canola meal, corn germ meal, sugar beet pulp, or wheat middlings compared with the corn starch diet. However, inclusion rate did not affect the calculated DE and ME or AID and ATTD of GE in any of the ingredients indicating that concentration of DE and ME in ingredients was independent of inclusion rate and utilization of energy from test ingredients was equally efficient between diets with 15% and 30% inclusion. Increased inclusion of fiber in the diet did not influence transit time in the small intestine, but reduced the time of first appearance of digesta in the feces indicating that transit time was reduced in the hindgut of pigs fed high-fiber diets. However, this had no impact on DE and ME or ATTD of GE in test ingredients. In conclusion, fiber reduced the DE and ME in the diet. However, inclusion rate of fiber-rich ingredients in diets did not affect calculated values for DE and ME in feed ingredients indicating that microbial capacity for fermentation of fiber in pigs is not overwhelmed by inclusion of 30% high-fiber ingredients in the diets.

Sharing adaptation knowledge across Europe: Evidence for the evaluation of Climate-ADAPT
Mattern, Kati ; Giannini, Valentina ; Downing, Claire ; Gomes, Ana ; Ramieri, Emiliano ; Karali, Eleni ; Capela Lourenco, T. ; Jong, F. de; Coninx, I. ; Marras, Serena ; Medri, Silvia ; Kazmierczak, Aleksandra - \ 2018
Bologna : ETC CCA (ETC/CCA Technical paper 2018/2) - 214 p.
This report (termed 'ETC/CCA Technical Paper') collects the annexes (“Key evidence”) supporting the outcomes of the evaluation of the European Climate Adaptation Platform (Climate-ADAPT), that are presented in the European Environment Agency (EEA) Report (2018) “Sharing adaptation knowledge across Europe – Evaluation of the European Climate Adaptation Platform”.
Legume abundance along successional and rainfall gradients in Neotropical forests
Gei, Maga ; Rozendaal, Danaë M.A. ; Poorter, Lourens ; Bongers, Frans ; Sprent, Janet I. ; Garner, Mira D. ; Aide, T.M. ; Andrade, José Luis ; Balvanera, Patricia ; Becknell, Justin M. ; Brancalion, Pedro H.S. ; Cabral, George A.L. ; César, Ricardo Gomes ; Chazdon, Robin L. ; Cole, Rebecca J. ; Colletta, Gabriel Dalla ; Jong, Ben De; Denslow, Julie S. ; Dent, Daisy H. ; Dewalt, Saara J. ; Dupuy, Juan Manuel ; Durán, Sandra M. ; Espírito Santo, Mário Marcos Do; Fernandes, G.W. ; Nunes, Yule Roberta Ferreira ; Finegan, Bryan ; Moser, Vanessa Granda ; Hall, Jefferson S. ; Hernández-Stefanoni, José Luis ; Junqueira, André B. ; Kennard, Deborah ; Lebrija-Trejos, Edwin ; Letcher, Susan G. ; Lohbeck, Madelon ; Marín-Spiotta, Erika ; Martínez-Ramos, Miguel ; Meave, Jorge A. ; Menge, Duncan N.L. ; Mora, Francisco ; Muñoz, Rodrigo ; Muscarella, Robert ; Ochoa-Gaona, Susana ; Orihuela-Belmonte, Edith ; Ostertag, Rebecca ; Peña-Claros, Marielos ; Pérez-García, Eduardo A. ; Piotto, Daniel ; Reich, Peter B. ; Reyes-García, Casandra ; Rodríguez-Velázquez, Jorge ; Romero-Pérez, I.E. ; Sanaphre-Villanueva, Lucía ; Sanchez-Azofeifa, Arturo ; Schwartz, Naomi B. ; Almeida, Arlete Silva De; Almeida-Cortez, Jarcilene S. ; Silver, Whendee ; Souza Moreno, Vanessa De; Sullivan, Benjamin W. ; Swenson, Nathan G. ; Uriarte, Maria ; Breugel, Michiel Van; Wal, Hans Van Der; Veloso, Maria Das Dores Magalhães ; Vester, Hans F.M. ; Vieira, Ima Célia Guimarães ; Zimmerman, Jess K. ; Powers, Jennifer S. - \ 2018
Nature Ecology & Evolution 2 (2018)7. - ISSN 2397-334X - p. 1104 - 1111.
The nutrient demands of regrowing tropical forests are partly satisfied by nitrogen-fixing legume trees, but our understanding of the abundance of those species is biased towards wet tropical regions. Here we show how the abundance of Leguminosae is affected by both recovery from disturbance and large-scale rainfall gradients through a synthesis of forest inventory plots from a network of 42 Neotropical forest chronosequences. During the first three decades of natural forest regeneration, legume basal area is twice as high in dry compared with wet secondary forests. The tremendous ecological success of legumes in recently disturbed, water-limited forests is likely to be related to both their reduced leaflet size and ability to fix N2, which together enhance legume drought tolerance and water-use efficiency. Earth system models should incorporate these large-scale successional and climatic patterns of legume dominance to provide more accurate estimates of the maximum potential for natural nitrogen fixation across tropical forests.
Timing of Avian Breeding in an Urbanised World
Jong, Maaike de; Eertwegh, Laura van den; Beskers, Ronald E. ; Vries, Peter P. de; Spoelstra, Kamiel ; Visser, Marcel E. - \ 2018
Ardea 106 (2018)1. - ISSN 0373-2266 - p. 31 - 38.
citizen science - hole breeding birds - light pollution - seasonal timing - urban gradient - urbanisation
A large part of the world is urbanised, and the process of urbanisation is ongoing. This causes dramatic alterations of species' habitat such as increased night light, sound levels and temperature, along with direct disturbance by human activity. We used eight years of citizen science data from ten common bird species breeding in nest boxes throughout The Netherlands to study the relationship between urbanisation and a key life history trait, timing of breeding. We used nightly light levels in the form of sky brightness and light emission as a proxy for urbanisation as the dramatic change of the night-time environment is a prominent effect of urbanisation. We expected birds to lay earlier in areas with more light at night, i.e. in more urbanised areas. We found, however, no relationship between light levels and seasonal timing in the ten species studied. A limitation of our study is that there was only limited data for the areas that were urbanised most (e.g. inside cities). Most nest box study areas are located in areas with a limited level of urbanisation, and hence with relatively low light levels of light at night. The lack of data on breeding birds in more urbanised environments, which is a rapidly expanding habitat for an increasing number of species worldwide, should be the focus of attention and citizen science would be highly suitable to also provide data for such areas.
Transmission of digital dermatitis in dairy cattle: population dynamics and host quantitative genetics
Biemans, Floor - \ 2018
University. Promotor(en): Mart de Jong, co-promotor(en): Piter Bijma. - Wageningen : Wageningen University - ISBN 9789463437639 - 204
Intact DNA purified from flow-sorted nuclei unlocks the potential of next-generation genome mapping and assembly in Solanum species
Gaiero, Paola ; Šimková, Hana ; Vrána, Jan ; Santiñaque, Federico F. ; López-Carro, Beatriz ; Folle, Gustavo A. ; Belt, José van de; Peters, Sander A. ; Doležel, Jaroslav ; Jong, Hans de - \ 2018
MethodsX 5 (2018). - ISSN 2215-0161 - p. 328 - 336.
BioNano genome mapping - Flow sorting - Genome finishing - HMW DNA isolation
Next-generation genome mapping through nanochannels (Bionano optical mapping) of plant genomes brings genome assemblies to the ‘nearly-finished’ level for reliable and detailed gene annotations and assessment of structural variations. Despite the recent progress in its development, researchers face the technical challenges of obtaining sufficient high molecular weight (HMW) nuclear DNA due to cell walls which are difficult to disrupt and to the presence of cytoplasmic polyphenols and polysaccharides that co-precipitate or are covalently bound to DNA and might cause oxidation and/or affect the access of nicking enzymes to DNA, preventing downstream applications. Here we describe important improvements for obtaining HMW DNA that we tested on Solanum crops and wild relatives. The methods that we further elaborated and refined focus on • Improving flexibility of using different tissues as source materials, like fast-growing root tips and young leaves from seedlings or in vitro plantlets.• Obtaining nuclei suspensions through either lab homogenizers or by chopping.• Increasing flow sorting efficiency using DAPI (4′,6-diamidino-2-phenylindole) and PI (propidium iodide) DNA stains, with different lasers (UV or 488 nm) and sorting platforms such as the FACSAria and FACSVantage flow sorters, thus making it appropriate for more laboratories working on plant genomics.The obtained nuclei are embedded into agarose plugs for processing and isolating uncontaminated HMW DNA, which is a prerequisite for nanochannel-based next-generation optical mapping strategies.
Origin and Processing Methods Slightly Affect Allergenic Characteristics of Cashew Nuts (Anacardium occidentale)
Reitsma, Marit ; Bastiaan-Net, Shanna ; Sijbrandij, Lutske ; Weert, Evelien de; Sforza, Stefano ; Gerth van Wijk, Roy ; Savelkoul, Huub F.J. ; Jong, Nicolette W. de; Wichers, Harry J. - \ 2018
Journal of Food Science 83 (2018)4. - ISSN 0022-1147 - p. 1153 - 1164.
2D electrophoresis - Anacardium occidentale - cashew - in vitro gastric digestion
The protein content and allergen composition was studied of cashews from 8 different origins (Benin, Brazil, Ghana, India, Ivory Coast, Mozambique, Tanzania, Vietnam), subjected to different in-shell heat treatments (steamed, fried, drum-roasted). On 2D electrophoresis, 9 isoforms of Ana o 1, 29 isoforms of Ana o 2 (11 of the acidic subunit, 18 of the basic subunit), and 8 isoforms of the large subunit of Ana o 3 were tentatively identified. Based on 1D and 2D electrophoresis, no difference in allergen content (Ana o 1, 2, 3) was detected between the cashews of different origins (P > 0.5), some small but significant differences were detected in allergen solubility between differently heated cashews. No major differences in N- and C-terminal microheterogeneity of Ana o 3 were detected between cashews of different origins. Between the different heat treatments, no difference was detected in glycation, pepsin digestibility, or IgE binding of the cashew proteins.
Analysis for low-molecular-weight carbohydrates is needed to account for all energy-contributing nutrients in some feed ingredients, but physical characteristics do not predict in vitro digestibility of dry matter
Navarro, D.M.D.L. ; Bruininx, E.M.A.M. ; Jong, L. de; Stein, H.H. - \ 2018
Journal of Animal Science 96 (2018)2. - ISSN 0021-8812 - p. 532 - 544.
Energy - In vitro digestibility - Physicochemical characteristics - Total dietary fiber
An experiment was conducted to quantify nutrient and fiber fractions of feed ingredients and to determine in vitro apparent ileal digestibility (IVAID) and in vitro apparent total tract digestibility (IVATTD) of DM and OM in each ingredient. Ten ingredients that vary in fiber concentration and composition were used: corn, wheat, soybean meal (SBM), canola meal, distillers dried grains with solubles (DDGS), corn germ meal, copra expellers, sugar beet pulp (SBP), synthetic cellulose (SF), and pectin. Correlations between chemical and physical characteristics of ingredients and IVAID and IVATTD of DM and OM were determined. The physical characteristics measured included bulk density, water-binding capacity (WBC), swelling, and viscosity. The analyzed GE was compared with values for GE calculated from all energy-contributing components. Results indicated that the analyzed chemical composition of most ingredients added to 100% or greater, except for DDGS, SBP, and SF, where nutrients added to only 94.29%, 88.90%, and 96.09%, respectively. The difference between the sum of the calculated GE of the analyzed components and the analyzed GE of the ingredients ranged from −2.25 MJ/kg in DDGS to 1.74 MJ/kg in pectin. No correlation was observed between swelling, WBC, or viscosity and IVAID or IVATTD of DM or OM. The concentration of insoluble dietary fiber (IDF) and total dietary fiber (TDF) was negatively correlated (P < 0.05) with IVAID and IVATTD of DM and OM. There was a tendency for NDF (r = −0.60) and ADF (r = −0.61) to be negatively correlated (P < 0.10) with IVAID of DM. However, no correlation was observed between the concentration of CP, GE, acid-hydrolyzed ether extract, lignin, or soluble dietary fiber and IVAID and IVATTD of DM and OM. The stronger correlations between IDF, TDF, and insoluble non-starch polysaccharides and IVAID and IVATTD of DM and OM than between ADF and NDF and IVAID and IVATTD of DM and OM indicate that the concentration of TDF in feed ingredients is a better predictor of the digestibility of DM and OM than values for NDF and ADF. In conclusion, the calculated GE of some feed ingredients was in agreement with the analyzed GE, which gives confidence that energy-contributing components were accounted for, but for DDGS and SBP, it was not possible to account for all analyzed GE. Concentrations of IDF and TDF, but not the physical characteristics of feed ingredients, may be used to estimate IVAID and IVATTD of DM and OM in feed ingredients.
Technische prestatie uitkomst in de stal
Jong, I.C. de; Gunnink, H. ; Hattum, T.G. van; Kempen, I. ; Baere, Kris De; Cardinaels, Sofie - \ 2018
De Pluimveehouderij 2018 (2018). - ISSN 0166-8250 - p. 57 - 59.
Vleeskuikenhouders die uitkomst in de stal als innovatief concept omarmen, geven aan dat ze positieve effecten zien op de productie, lager antibioticagebruik en minder ziektegevoeligheid. Deze veronderstelde positieve effecten ten opzichte van uitkomen in de broederij en het vervolgens transporteren van eendagskuikens is nu wetenschappelijk onderzocht.
Life histories of an invasive and native ladybird under field experimental conditions in a temperate climate
Raak-van den Berg, C.L. ; Jong, Peter W. de; Gort, Gerrit ; Manly, Bryan F.J. ; Lenteren, Joop C. van - \ 2018
Entomologia Experimentalis et Applicata 166 (2018)3. - ISSN 0013-8703 - p. 151 - 161.
Harmonia axyridis - Adalia bipunctata - Coccinellidae - Coleoptera - Competition between species - Field experimental study - Immature development - Immature survival - Intraguild predation - Life table - Northwestern Europe - Tilia × europaea
Among characteristics that are thought to determine the success of invasive species, life-history traits feature prominently. However, in most cases, these have been determined under laboratory conditions. Here, we use a field set-up to determine immature development time and survival of invasive Harmonia axyridis (Pallas) and native Adalia bipunctata L. (both Coleoptera: Coccinellidae). On caged Tilia × europaea L. cv. Pallida trees (Malvaceae) with ample amounts of aphid food, we introduced freshly hatched larvae of a single or of both ladybird species and followed their development until emergence of adults. Under the condition of ample prey availability, both ladybird species apparently hardly interacted and intraguild predation did not cause significant mortality. Development time of both species is in line with data from laboratory tests under controlled conditions. Immature survival can reach high levels, but is considerably higher for H. axyridis (44-100%) than for A. bipunctata (11-77%), resulting in faster increase of H. axyridis populations, which is one of the factors that may explain its invasion success.
Aardappeldemodag 2018: Sterke schakels verbinden
Ampt-de Jong, Marieke ; Brouwer, Thie Arend ; Mol-van de Erve, Leanne ; Tramper, Marcel - \ 2018
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