Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

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

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Effect of dietary replacement of fishmeal by insect meal on growth performance, blood profiles and economics of growing pigs in Kenya
Chia, Shaphan Y. ; Tanga, Chrysantus M. ; Osuga, Isaac M. ; Alaru, Alphonce O. ; Mwangi, David M. ; Githinji, Macdonald ; Subramanian, Sevgan ; Fiaboe, Komi K.M. ; Ekesi, Sunday ; Loon, Joop J.A. van; Dicke, Marcel - \ 2019
Animals 9 (2019)10. - ISSN 2076-2615
Alternative protein - Animal feeds - Blood parameters - Cost benefit analysis - Growing pigs - Insect larval meal - Return on investment

Pig production is one of the fastest growing livestock sectors. Development of this sector is hampered by rapidly increasing costs of fishmeal (FM), which is a common protein source in animal feeds. Here, we explored the potential of substituting FM with black soldier fly larval meal (BSFLM) on growth and blood parameters of pigs as well as economic aspects. At weaning, 40 hybrid pigs, i.e., crossbreeds of purebred Large White and Landrace were randomly assigned to five iso-nitrogenous and iso-energetic dietary treatments: Control (0% BSFLM and 100% FM (T0)), and FM replaced at 25% (T25), 50% (T50), 75% (T75) and 100% (T100) with BSFLM. Average daily feed intake (ADFI), average daily gain (ADG), body weight gain (BWG) and feed conversion ratio (FCR) were calculated for the whole trial. Hematological and serum biochemical parameters, the cost– benefit ratio (CBR) and return on investment (RoI) were evaluated. No significant effect of diet type was observed on feed intake and daily weight gain. Red or white blood cell indices did not differ among diets. Pigs fed T25, T75 and T100, had lower platelet counts compared to T0 and T50. Dietary inclusion of BSFLM did not affect blood total cholesterol, triglycerides, low-density lipoprotein and high-density lipoprotein. CBR and RoI were similar for the various diets. In conclusion, BSFLM is a suitable and cost-effective alternative to fishmeal in feed for growing pigs.

Disentangling agronomic and economic yield gaps in Ethiopian wheat based systems for better targeting of development interventions (Yield Gap Wheat Ethiopia) : Report 3: National yield gap analysis and its components
Morley, Tomas ; Silva, J.V. ; Dijk, M. van; Reidsma, P. ; Loon, M.P. van; Ittersum, M.K. van - \ 2019
Wageningen : Wageningen University & Research - 13 p.
Disentangling agronomic and economic yield gaps in Ethiopian wheat based systems for better targeting of development interventions (Yield Gap Wheat Ethiopia) : Report #4: Wheat yield gaps in the Ethiopian highlands: Magnitude, drivers and policy implications
Silva, J.V. ; Reidsma, P. ; Loon, M.P. van; Ittersum, M.K. van - \ 2019
Wageningen : Wageningen University & Research - 28 p.
Effects of selected insecticides on Black Soldier Fly (Hermetia illucens) larvae
Meijer, N.P. ; Rijk, T.C. de; Loon, J.J.A. van; Fels, H.J. van der - \ 2019
Aflatoxin B1 Conversion by Black Soldier Fly (Hermetia illucens) Larval Enzyme Extracts
Meijer, Nathan ; Stoopen, Geert ; Fels-Klerx, H.J. van der; Loon, Joop J.A. van; Carney, John ; Bosch, Guido - \ 2019
Toxins 11 (2019)9. - ISSN 2072-6651
aflatoxin - black soldier fly - BSFL - cytochrome P450 - enzyme induction - Hermetia illucens - metabolic conversion - mycotoxin - S9 fraction

The larvae of the black soldier fly (Hermetia illucens L., BSFL) have received increased industrial interest as a novel protein source for food and feed. Previous research has found that insects, including BSFL, are capable of metabolically converting aflatoxin B1 (AFB1), but recovery of total AFB1 is less than 20% when accounting for its conversion to most known metabolites. The aim of this study was to examine the conversion of AFB1 by S9 extracts of BSFL reared on substrates with or without AFB1. Liver S9 of Aroclor-induced rats was used as a reference. To investigate whether cytochrome P450 enzymes are involved in the conversion of AFB1, the inhibitor piperonyl butoxide (PBO) was tested in a number of treatments. The results showed that approximately 60% of AFB1 was converted to aflatoxicol and aflatoxin P1. The remaining 40% of AFB1 was not converted. Cytochrome P450s were indeed responsible for metabolic conversion of AFB1 into AFP1, and a cytoplasmic reductase was most likely responsible for conversion of AFB1 into aflatoxicol.

Versterking Grebbedijk als voorbeeld van participatie volgens de Omgevingswet
Klostermann, J. ; Buuren, Michael van; Loon-Steensma, Jantsje van; Pedroli, Bas - \ 2019
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2958) - 71
In consultation with partners from the HWBP project Grebbedijk, Rijkswaterstaat Oost-Nederland (RWS-ON) has commissioned Wageningen Environmental Research (WENR) for an exploratory studyto create an action perspective for the upcoming introduction of the Environmental Act and the introduction at RWS of the term “Sustainable Living Environment”. In 2018, in-depth interviews were held with project leaders of river widening and dyke improvement projects and with RWS advisers. The report includes a case study of the Grebbedijk, starting with a historical analysis. The integral approach and the participatory approach have been studied in more detail on the basis of the “Dijkversterking Grebbedijk” project of 2016-2018. The emphasis was on the participative, spatial design process that was used in this dyke improvement project. Conclusions include that structural reflection helps with complex processes and with the introduction of new methods such as the new Environment Act; and that trust and reliability are crucial in complex dyke improvement projects
Impacts of intensifying or expanding cereal cropping in sub-Saharan Africa on greenhouse gas emissions and food security
Loon, Marloes P. van; Hijbeek, Renske ; Berge, Hein F.M. ten; Sy, Veronique De; Broeke, Guus A. ten; Solomon, Dawit ; Ittersum, Martin K. van - \ 2019
Global Change Biology 25 (2019)11. - ISSN 1354-1013 - p. 3720 - 3730.
fertilizer - food self-sufficiency - intensification - land use conversion - nitrogen - nutrient use efficiency - yield gaps

Cropping is responsible for substantial emissions of greenhouse gasses (GHGs) worldwide through the use of fertilizers and through expansion of agricultural land and associated carbon losses. Especially in sub-Saharan Africa (SSA), GHG emissions from these processes might increase steeply in coming decades, due to tripling demand for food until 2050 to match the steep population growth. This study assesses the impact of achieving cereal self-sufficiency by the year 2050 for 10 SSA countries on GHG emissions related to different scenarios of increasing cereal production, ranging from intensifying production to agricultural area expansion. We also assessed different nutrient management variants in the intensification. Our analysis revealed that irrespective of intensification or extensification, GHG emissions of the 10 countries jointly are at least 50% higher in 2050 than in 2015. Intensification will come, depending on the nutrient use efficiency achieved, with large increases in nutrient inputs and associated GHG emissions. However, matching food demand through conversion of forest and grasslands to cereal area likely results in much higher GHG emissions. Moreover, many countries lack enough suitable land for cereal expansion to match food demand. In addition, we analysed the uncertainty in our GHG estimates and found that it is caused primarily by uncertainty in the IPCC Tier 1 coefficient for direct N2O emissions, and by the agronomic nitrogen use efficiency (N-AE). In conclusion, intensification scenarios are clearly superior to expansion scenarios in terms of climate change mitigation, but only if current N-AE is increased to levels commonly achieved in, for example, the United States, and which have been demonstrated to be feasible in some locations in SSA. As such, intensifying cereal production with good agronomy and nutrient management is essential to moderate inevitable increases in GHG emissions. Sustainably increasing crop production in SSA is therefore a daunting challenge in the coming decades.

Ending hunger with silkworms
Oonincx, D.G.A.B. ; Loon, J.J.A. van - \ 2019
Protein supplementation elicits greater gains in maximal oxygen uptake capacity and stimulates lean mass accretion during prolonged endurance training: a double-blind randomized controlled trial
Knuiman, Pim ; Loon, Luc J.C. van; Wouters, Jeroen ; Hopman, Maria ; Mensink, Marco - \ 2019
American Journal of Clinical Nutrition 110 (2019)2. - ISSN 0002-9165 - p. 508 - 518.
body composition - endurance training - maximal oxygen uptake capacity - protein supplementation - skeletal muscle oxidative capacity

BACKGROUND: Endurance training induces numerous cardiovascular and skeletal muscle adaptations, thereby increasing maximal oxygen uptake capacity (VO2max). Whether protein supplementation enhances these adaptations remains unclear. OBJECTIVE: The present study was designed to determine the impact of protein supplementation on changes in VO2max during prolonged endurance training. METHODS: We used a double-blind randomized controlled trial with repeated measures among 44 recreationally active, young males. Subjects performed 3 endurance training sessions per week for 10 wk. Supplements were provided immediately after each exercise session and daily before sleep, providing either protein (PRO group; n = 19; 21.5 ± 0.4 y) or an isocaloric amount of carbohydrate as control (CON group; n = 21; 22.5 ± 0.5 y). The VO2max, simulated 10-km time trial performance, and body composition (dual-energy X-ray absorptiometry) were measured before and after 5 and 10 wk of endurance training. Fasting skeletal muscle tissue samples were taken before and after 5 and 10 wk to measure skeletal muscle oxidative capacity, and fasting blood samples were taken every 2 wk to measure hematological factors. RESULTS: VO2max increased to a greater extent in the PRO group than in the CON group after 5 wk (from 49.9 ± 0.8 to 54.9 ± 1.1 vs 50.8 ± 0.9 to 53.0 ± 1.1 mL · kg-1 · min-1; P < 0.05) and 10 wk (from 49.9 ± 0.8 to 55.4 ± 0.9 vs 50.8 ± 0.9 to 53.9 ± 1.2 mL · kg-1 · min-1; P < 0.05). Lean body mass increased in the PRO group whereas lean body mass in the CON group remained stable during the first 5 wk (1.5 ± 0.2 vs 0.1 ± 0.3 kg; P < 0.05) and after 10 wk (1.5 ± 0.3 vs 0.4 ± 0.3 kg; P < 0.05). Throughout the intervention, fat mass reduced significantly in the PRO group and there were no changes in the CON group after 5 wk (-0.6 ± 0.2 vs -0.1 ± 0.2 kg; P > 0.05) and 10 wk (-1.2 ± 0.4 vs -0.2 ± 0.2 kg; P < 0.05). CONCLUSIONS: Protein supplementation elicited greater gains in VO2max and stimulated lean mass accretion but did not improve skeletal muscle oxidative capacity and endurance performance during 10 wk of endurance training in healthy, young males. This trial was registered at clinicaltrials.gov as NCT03462381.

High Versus low Dietary Protein Intake and Bone Health in Older Adults: a Systematic Review and Meta-Analysis
Groenendijk, Inge ; Boeft, L. den; Loon, Luc J.C. van; Groot, Lisette C.P.G.M. de - \ 2019
Computational and Structural Biotechnology Journal 17 (2019). - ISSN 2001-0370 - p. 1101 - 1112.
Bone - Bone density - Fractures - Older adults - Protein

Protein may play a beneficial role in the prevention of bone loss and in slowing down osteoporosis. The effect of dietary protein may be different in older adults compared to younger adults, since this population has a greater need for protein. The aim of this systematic review and meta-analysis was to investigate the impact of a dietary protein intake above the Recommended Dietary Allowance (RDA) of 0.8 g/kg body weight/day from any source on Bone Mineral Density (BMD)/Bone Mineral Content (BMC), bone turnover markers, and fracture risk in older adults compared to a lower dietary protein intake. A systematic search was conducted through October 2018 in 3 databases: CENTRAL, MEDLINE, and EMBASE. We included all prospective cohort studies and Randomized Controlled Trials (RCTs) among adults aged ≥65 years that examined the relation between protein intake on bone health outcomes. Two investigators independently conducted abstract and full-text screenings, data extractions, and risk of bias assessments. Authors were contacted for missing data. After screening of 523 records, twelve cohort studies and one RCT were included. Qualitative evaluation showed a positive trend between higher protein intakes and higher femoral neck and total hip BMD. Meta-analysis of four cohort studies showed that higher protein intakes resulted in a significant decrease in hip fractures (pooled hazard ratio: 0.89; 95% confidence interval: 0.84, 0.94). This systematic review supports that a protein intake above the current RDA may reduce hip fracture risk and may play a beneficial role in BMD maintenance and loss in older adults.

The environmental potential of the conversion of organic resources by black soldier fly larvae
Zanten, H.H.E. van; Zamprogna, A. ; Veenenbos, M.E. ; Meijer, Nathan ; Fels, I. van der; Loon, J.J.A. van; Bosch, G. - \ 2019
In: Book of Abstracts of the 70th Annual Meeting of the European Federation of Animal Science. - Wageningen Academic Publishers (EAAP books of abstracts ) - ISBN 9789086863396 - p. 157 - 157.
Leucine coingestion augments the muscle protein synthetic response to the ingestion of 15 g of protein following resistance exercise in older men
Holwerda, Andrew M. ; Paulussen, Kevin J.M. ; Overkamp, Maarten ; Goessens, Joy P.B. ; Kramer, Irene-Fleur ; Wodzig, Will K.W.H. ; Verdijk, Lex B. ; Groot, Lisette C.P.G.M. De; Loon, Luc J.C. Van - \ 2019
American Journal of Physiology. Endocrinology and Metabolism 317 (2019)3. - ISSN 0193-1849 - p. E473 - E482.
Older adults have shown an attenuated postexercise increase in muscle protein synthesis rates following ingestion of smaller amounts of protein compared with younger adults. Consequently, it has been suggested that older adults require the ingestion of more protein to increase postexercise muscle protein synthesis rates compared with younger adults. We investigated whether coingestion of 1.5 g of free leucine with a single 15-g bolus of protein further augments the postprandial muscle protein synthetic response during recovery from resistance-type exercise in older men. Twenty-four healthy older men (67 ± 1 yr) were randomly assigned to ingest 15 g of milk protein concentrate (MPC80) with (15G+LEU; n = 12) or without (15G; n = 12) 1.5 g of free leucine after performing a single bout of resistance-type exercise. Postprandial protein digestion and amino acid absorption kinetics, whole body protein metabolism, and postprandial myofibrillar protein synthesis rates were assessed using primed, continuous infusions with l-[ring-2H5]phenylalanine, l-[ring-2H2]tyrosine, and l-[1-13C]leucine combined with ingestion of intrinsically l-[1-13C]phenylalanine-labeled milk protein. A total of 70 ± 1% (10.5 ±0.2 g) and 75 ± 2% (11.2 ± 0.3 g) of the protein-derived amino acids were released in the circulation during the 6-h postexercise recovery phase in 15G+LEU and 15G, respectively (P < 0.05). Postexercise myofibrillar protein synthesis rates were 16% (0.058 ± 0.003 vs. 0.049 ± 0.002%/h, P < 0.05; based on l-[ring-2H5]phenylalanine) and 19% (0.071 ± 0.003 vs. 0.060 ± 0.003%/h, P < 0.05; based on l-[1-13C]leucine) greater in 15G+LEU compared with 15G. Leucine coingestion further augments the postexercise muscle protein synthetic response to the ingestion of a single 15-g bolus of protein in older men.
Growth and safety assessment of feed streams for black soldier fly larvae: A case study with aquaculture sludge
Schmitt, Eric ; Belghit, Ikram ; Johansen, Johan ; Leushuis, Raymond ; Lock, Erik Jan ; Melsen, Diede ; Ramasamy Shanmugam, Ram Kathirampatti ; Loon, Joop Van ; Paul, Aman - \ 2019
Animals 9 (2019)4. - ISSN 2076-2615
Aquaculture - Black soldier fly larvae - Mineral composition - Safety risks - Sludge

The production of food is an intensive source of environmental impact. In aquaculture, one source of impact is solid waste, which contains high concentrations of minerals, other nutrients, and metals. The larvae of Hermetia illucens are capable of consuming this material, but applying technology that is based on these larvae for managing waste streams, like those from aquaculture, requires careful examination of safety risks. A study is performed examining the growth performance of larvae that were fed on solid aquaculture waste. Subsequently, a thorough analysis of safety risks from inorganics, with detailed the results on microelements that have previously received little attention in the literature, is performed to serve as a guideline for how to assess the safety of waste streams such as these. Findings confirm existing results in the literature that Cd is bioaccumulative, but also that other elements, including Hg, Mn, and especially K, are bioaccumulative. To the authors’ knowledge, this is the first research where the accumulation of Ag is also tested. The results of these tests are explained within the context of regulations in various countries where Hermetia illucens is cultivated, serving as a reference for practitioners to rigorously screen out high risk feed streams that they may consider using as feed sources. It is intended that these references and the demonstrated accumulation of a range of elements motivate comprehensive industry safety practices when evaluating new feed sources.

Klimaatadaptatiedijk: Duurzaam en Toekomstgericht
Loon-Steensma, Jantsje van - \ 2019
Twenty-three unsolved problems in hydrology (UPH)–a community perspective
Blöschl, Günter ; Bierkens, Marc F.P. ; Chambel, Antonio ; Cudennec, Christophe ; Destouni, Georgia ; Fiori, Aldo ; Kirchner, James W. ; McDonnell, Jeffrey J. ; Savenije, Hubert H.G. ; Sivapalan, Murugesu ; Stumpp, Christine ; Toth, Elena ; Volpi, Elena ; Carr, Gemma ; Lupton, Claire ; Salinas, Josè ; Széles, Borbála ; Viglione, Alberto ; Aksoy, Hafzullah ; Allen, Scott T. ; Amin, Anam ; Andréassian, Vazken ; Arheimer, Berit ; Aryal, Santosh K. ; Baker, Victor ; Bardsley, Earl ; Barendrecht, Marlies H. ; Bartosova, Alena ; Batelaan, Okke ; Berghuijs, Wouter R. ; Beven, Keith ; Blume, Theresa ; Bogaard, Thom ; Borges de Amorim, Pablo ; Böttcher, Michael E. ; Boulet, Gilles ; Breinl, Korbinian ; Brilly, Mitja ; Brocca, Luca ; Buytaert, Wouter ; Castellarin, Attilio ; Castelletti, Andrea ; Chen, Xiaohong ; Chen, Yangbo ; Chen, Yuanfang ; Chifflard, Peter ; Claps, Pierluigi ; Clark, Martyn P. ; Collins, Adrian L. ; Croke, Barry ; Dathe, Annette ; David, Paula C. ; Barros, Felipe P.J. de; Rooij, Gerrit de; Baldassarre, Giuliano Di; Driscoll, Jessica M. ; Duethmann, Doris ; Dwivedi, Ravindra ; Eris, Ebru ; Farmer, William H. ; Feiccabrino, James ; Ferguson, Grant ; Ferrari, Ennio ; Ferraris, Stefano ; Fersch, Benjamin ; Finger, David ; Foglia, Laura ; Fowler, Keirnan ; Gartsman, Boris ; Gascoin, Simon ; Gaume, Eric ; Gelfan, Alexander ; Geris, Josie ; Gharari, Shervan ; Gleeson, Tom ; Glendell, Miriam ; Gonzalez Bevacqua, Alena ; González-Dugo, María P. ; Grimaldi, Salvatore ; Gupta, A.B. ; Guse, Björn ; Han, Dawei ; Hannah, David ; Harpold, Adrian ; Haun, Stefan ; Heal, Kate ; Helfricht, Kay ; Herrnegger, Mathew ; Hipsey, Matthew ; Hlaváčiková, Hana ; Hohmann, Clara ; Holko, Ladislav ; Hopkinson, Christopher ; Hrachowitz, Markus ; Illangasekare, Tissa H. ; Inam, Azhar ; Innocente, Camyla ; Istanbulluoglu, Erkan ; Jarihani, Ben ; Kalantari, Zahra ; Kalvans, Andis ; Khanal, Sonu ; Khatami, Sina ; Kiesel, Jens ; Kirkby, Mike ; Knoben, Wouter ; Kochanek, Krzysztof ; Kohnová, Silvia ; Kolechkina, Alla ; Krause, Stefan ; Kreamer, David ; Kreibich, Heidi ; Kunstmann, Harald ; Lange, Holger ; Liberato, Margarida L.R. ; Lindquist, Eric ; Link, Timothy ; Liu, Junguo ; Loucks, Daniel Peter ; Luce, Charles ; Mahé, Gil ; Makarieva, Olga ; Malard, Julien ; Mashtayeva, Shamshagul ; Maskey, Shreedhar ; Mas-Pla, Josep ; Mavrova-Guirguinova, Maria ; Mazzoleni, Maurizio ; Mernild, Sebastian ; Misstear, Bruce Dudley ; Montanari, Alberto ; Müller-Thomy, Hannes ; Nabizadeh, Alireza ; Nardi, Fernando ; Neale, Christopher ; Nesterova, Nataliia ; Nurtaev, Bakhram ; Odongo, Vincent O. ; Panda, Subhabrata ; Pande, Saket ; Pang, Zhonghe ; Papacharalampous, Georgia ; Perrin, Charles ; Pfister, Laurent ; Pimentel, Rafael ; Polo, María J. ; Post, David ; Prieto Sierra, Cristina ; Ramos, Maria Helena ; Renner, Maik ; Reynolds, José Eduardo ; Ridolfi, Elena ; Rigon, Riccardo ; Riva, Monica ; Robertson, David E. ; Rosso, Renzo ; Roy, Tirthankar ; Sá, João H.M. ; Salvadori, Gianfausto ; Sandells, Mel ; Schaefli, Bettina ; Schumann, Andreas ; Scolobig, Anna ; Seibert, Jan ; Servat, Eric ; Shafiei, Mojtaba ; Sharma, Ashish ; Sidibe, Moussa ; Sidle, Roy C. ; Skaugen, Thomas ; Smith, Hugh ; Spiessl, Sabine M. ; Stein, Lina ; Steinsland, Ingelin ; Strasser, Ulrich ; Su, Bob ; Szolgay, Jan ; Tarboton, David ; Tauro, Flavia ; Thirel, Guillaume ; Tian, Fuqiang ; Tong, Rui ; Tussupova, Kamshat ; Tyralis, Hristos ; Uijlenhoet, Remko ; Beek, Rens van; Ent, Ruud J. van der; Ploeg, Martine van der; Loon, Anne F. Van; Meerveld, Ilja van; Nooijen, Ronald van; Oel, Pieter R. van; Vidal, Jean Philippe ; Freyberg, Jana von; Vorogushyn, Sergiy ; Wachniew, Przemyslaw ; Wade, Andrew J. ; Ward, Philip ; Westerberg, Ida K. ; White, Christopher ; Wood, Eric F. ; Woods, Ross ; Xu, Zongxue ; Yilmaz, Koray K. ; Zhang, Yongqiang - \ 2019
Hydrological Sciences Journal 64 (2019)10. - ISSN 0262-6667 - p. 1141 - 1158.
hydrology - interdisciplinary - knowledge gaps - research agenda - science questions

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come.

Use of visual and olfactory cues of flowers of two brassicaceous species by insect pollinators
Barragán-Fonseca, Katherine Y. ; Loon, Joop J.A. van; Dicke, Marcel ; Lucas-Barbosa, Dani - \ 2019
Ecological Entomology (2019). - ISSN 0307-6946
Odour cues - plant volatiles - pollinators - post-pollination changes - visual cues

1. Pollinating insects exploit visual and olfactory cues associated with flower traits indicative of flower location and reward quality. Pollination can induce changes in these flower-associated cues, thereby influencing the behaviour of flower visitors. 2. This study investigated the main cues exploited by the syrphid fly Episyrphus balteatus and the butterfly Pieris brassicae when visiting flowers of Brassica nigra and Raphanus sativus plants. Whether pollen is used as a cue and whether pollination-induced changes affect flower volatile emission and the behavioural responses of the two pollinator species were also studied. 3. Pollinator preference was investigated by offering visual and olfactory cues individually as well as simultaneously in two-choice bioassays. Plant treatments included emasculation, hand-pollination and untreated control plants. The composition of flower volatiles from pollinated and unpollinated control plants was analysed by gas chromatography-mass spectrometry. 4. Both pollinators exhibited a strong bias for visual cues over olfactory cues. Neither pollinator used pollen as a cue. However, E. balteatus discriminated between newly opened and long-open flowers at short distance only when pollen was available. Flower visits by pollinators were influenced by pollination-induced changes in B. nigra but not R. sativus flowers. Pieris brassicae only responded to pollination-induced changes when visual and olfactory cues were offered simultaneously. The blend of volatiles emitted by B. nigra, but not R. sativus inflorescences was affected by pollination. 5. Collectively, the findings of this study show that different pollinators exploit different visual and olfactory traits when searching for flowers of two brassicaceous plant species.

Fertiliser use and soil carbon sequestration: trade-offs and opportunities
Hijbeek, R. ; Loon, M.P. van; Ittersum, M.K. van - \ 2019
Frederiksberg : (Working paper CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) 264) - 21 p.
Current initiatives to store carbon in soils as a measure to mitigate climate change are gaining momentum. Agriculture plays an important role in soil carbon initiatives, as almost 40% of the world's soils are currently used as cropland and grassland. Thus, a major research and policy question is how different agricultural management practices affect soil carbon sequestration. This working paper focuses on the impact of mineral fertiliser use on soil carbon sequestration, including synergies with the use of organic inputs (for example crop residues, animal manure) and trade-offs with greenhouse gas (GHG) emissions. Findings from scientific literature show that fertiliser use contributes to soil carbon sequestration in agriculture by increasing biomass production and by improving carbon:nitrogen (C:N) ratios of residues returned to the field. The use of mineral fertiliser can also support the maintenance of carbon stocks in non-agricultural land if improved fertility on agricultural land reduces demand for land conversion. Combining organic inputs with mineral fertiliser seems most promising to sequester carbon in agricultural soils. Increasing nutrient inputs (either organic or mineral fertilisers) may however lead to trade-offs with GHG emissions such as N2O. Improving the agronomic nitrogen use efficiency of nutrient inputs (i.e., additional grain yield per kg N applied) can alleviate this trade-off. While soil carbon sequestration can benefit soil fertility under some conditions and compensate for some GHG emissions related to agriculture (first assessments indicate up to 25% of the emissions related to crop production, depending on region and cropping system), it seems unlikely it can compensate for GHG emissions from other economic sectors. If soil carbon sequestration is a policy objective, priorities should be areas with higher storage potential (wetter and colder climates) and/or regions where synergies with soil fertility and food security are likely to occur (for example farming systems in tr!
opical regions, on sandy soils and/or when cultivating more specialized crops). However, regions with the highest storage potential most likely do not overlap with regions where the largest benefits for soil fertility and food security occur.
Watertekorten in landbouw terugdringen met hergebruik industrieel restwater
Bartholomeus, Ruud ; Huijgevoort, Marjolein H.J. Van; Rozema, J. ; Loon, A. van - \ 2019
Water Matters : Kenniskatern voor Waterprofessionals - Dutch edition (2019). - p. 20 - 23.
In plaats van restwater uit de industrie op het oppervlaktewater te lozen, kan het worden benut voor droogtebestrijding in de landbouw. Bavaria geeft concrete invulling aan hergebruik van hun gezuiverd restwater door agrarische bedrijven in de omgeving. Een test is uitgevoerd met restwater van de waterzuivering van Bavaria door dit te gebruiken voor subirrigatie in een landbouwperceel. De resultaten wijzen uit dat subirrigatie zorgde voor een dusdanige verhoging van de grondwaterstand en daarmee ook van het bodemvochtgehalte, dat de vochtvoorziening van het gewas verbeterde. Door industrieel restwater niet ongebruikt af te voeren, maar te benutten voor droogtebestrijding, is terugdringen van watertekorten mogelijk.
No effect of 25-hydroxyvitamin D supplementation on the skeletal muscle transcriptome in vitamin D deficient frail older adults
Hangelbroek, Roland W.J. ; Vaes, Anouk M.M. ; Boekschoten, Mark V. ; Verdijk, Lex B. ; Hooiveld, Guido J.E.J. ; Loon, Luc J.C. van; Groot, Lisette C.P.G.M. De; Kersten, Sander - \ 2019
BMC Geriatrics 19 (2019). - ISSN 1471-2318
25-hydroxyvitamin D - older adults - skeletal muscle - transcriptomics - Vitamin D

Objective: Vitamin D deficiency is common among older adults and has been linked to muscle weakness. Vitamin D supplementation has been proposed as a strategy to improve muscle function in older adults. The aim of this study was to investigate the effect of calcifediol (25-hydroxycholecalciferol) on whole genome gene expression in skeletal muscle of vitamin D deficient frail older adults. Methods: A double-blind placebo-controlled trial was conducted in vitamin D deficient frail older adults (aged above 65), characterized by blood 25-hydroxycholecalciferol concentrations between 20 and 50 nmol/L. Subjects were randomized across the placebo group and the calcifediol group (10 μg per day). Muscle biopsies were obtained before and after 6 months of calcifediol (n = 10) or placebo (n = 12) supplementation and subjected to whole genome gene expression profiling using Affymetrix HuGene 2.1ST arrays. Results: Expression of the vitamin D receptor gene was virtually undetectable in human skeletal muscle biopsies, with Ct values exceeding 30. Blood 25-hydroxycholecalciferol levels were significantly higher after calcifediol supplementation (87.3 ± 20.6 nmol/L) than after placebo (43.8 ± 14.1 nmol/L). No significant difference between treatment groups was observed on strength outcomes. The whole transcriptome effects of calcifediol and placebo were very weak, as indicated by the fact that correcting for multiple testing using false discovery rate did not yield any differentially expressed genes using any reasonable cut-offs (all q-values ~ 1). P-values were uniformly distributed across all genes, suggesting that low p-values are likely to be false positives. Partial least squares-discriminant analysis and principle component analysis was unable to separate treatment groups. Conclusion: Calcifediol supplementation did not significantly affect the skeletal muscle transcriptome in frail older adults. Our findings indicate that vitamin D supplementation has no effects on skeletal muscle gene expression, suggesting that skeletal muscle may not be a direct target of vitamin D in older adults. Trial registration: This study was registered at clinicaltrials.gov as NCT02349282 on January 28, 2015.

Door eendrachtige samenwerking : de geschiedenis van de aardappelveredeling in Nederland, van hobby tot industrie 1888-2018
Loon, Jan van - \ 2019
Wageningen University. Promotor(en): J.S.C. Wiskerke; E.T. Lammerts van Bueren, co-promotor(en): P. J. van Cruyningen. - Wageningen : Wageningen University - ISBN 9789463434188 - 407
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