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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Loss rates of honey bee colonies during winter 2017/18 in 36 countries participating in the COLOSS survey, including effects of forage sources
Gray, Alison ; Brodschneider, Robert ; Adjlane, Noureddine ; Ballis, Alexis ; Brusbardis, Valters ; Charrière, Jean Daniel ; Chlebo, Robert ; F. Coffey, Mary ; Cornelissen, Bram ; Amaro da Costa, Cristina ; Csáki, Tamás ; Dahle, Bjørn ; Danihlík, Jiří ; Dražić, Marica Maja ; Evans, Garth ; Fedoriak, Mariia ; Forsythe, Ivan ; Graaf, Dirk de; Gregorc, Aleš ; Johannesen, Jes ; Kauko, Lassi ; Kristiansen, Preben ; Martikkala, Maritta ; Martín-Hernández, Raquel ; Medina-Flores, Carlos Aurelio ; Mutinelli, Franco ; Patalano, Solenn ; Petrov, Plamen ; Raudmets, Aivar ; Ryzhikov, Vladimir A. ; Simon-Delso, Noa ; Stevanovic, Jevrosima ; Topolska, Grazyna ; Uzunov, Aleksandar ; Vejsnaes, Flemming ; Williams, Anthony ; Zammit-Mangion, Marion ; Soroker, Victoria - \ 2019
Journal of Apicultural Research 58 (2019)4. - ISSN 0021-8839 - p. 479 - 485.
Apis mellifera - beekeeping - citizen science - colony winter losses - forage sources - monitoring - mortality - survey

This short article presents loss rates of honey bee colonies over winter 2017/18 from 36 countries, including 33 in Europe, from data collected using the standardized COLOSS questionnaire. The 25,363 beekeepers supplying data passing consistency checks in total wintered 544,879 colonies, and reported 26,379 (4.8%, 95% CI 4.7–5.0%) colonies with unsolvable queen problems, 54,525 (10.0%, 95% CI 9.8–10.2%) dead colonies after winter and another 8,220 colonies (1.5%, 95% CI 1.4–1.6%) lost through natural disaster. This gave an overall loss rate of 16.4% (95% CI 16.1–16.6%) of honey bee colonies during winter 2017/18, but this varied greatly from 2.0 to 32.8% between countries. The included map shows relative risks of winter loss at regional level. The analysis using the total data-set confirmed findings from earlier surveys that smaller beekeeping operations with at most 50 colonies suffer significantly higher losses than larger operations (p <.001). Beekeepers migrating their colonies had significantly lower losses than those not migrating (p <.001), a different finding from previous research. Evaluation of six different forage sources as potential risk factors for colony loss indicated that intensive foraging on any of five of these plant sources (Orchards, Oilseed Rape, Maize, Heather and Autumn Forage Crops) was associated with significantly higher winter losses. This finding requires further study and explanation. A table is included giving detailed results of loss rates and the impact of the tested forage sources for each country and overall.

Quantifying calf mortality on dairy farms: Challenges and solutions
Santman-Berends, I.M.G.A. ; Schukken, Y.H. ; Schaik, G. van - \ 2019
Journal of Dairy Science 102 (2019)7. - ISSN 0022-0302 - p. 6404 - 6417.
census data - dairy calves - monitoring - mortality

In the Netherlands, the mortality rate of ear-tagged calves <1 yr is one of the indicators that is continuously monitored in census data and is defined as the number of deceased calves relative to the number of calf-days-at-risk. In 2017, yearly calf mortality rates were published in the lay press and resulted in discussions about the calculation of this parameter among stakeholders because the same parameter appeared to be calculated in many different ways by different organizations. These diverse definitions of calf mortality answered different aims such as early detection of deviations, monitoring trends, or providing insight into herd-specific results, but were difficult to understand by stakeholders. The aim of this study was to evaluate several definitions of calf mortality for scientific validity, usefulness for policymakers, and comprehensibility by farmers. Based on expert consultations, 10 definitions for calf mortality were evaluated that assessed different age categories, time periods, and denominators. Differences in definitions appeared to have a large effect on the magnitude of mortality. For example, with the original mortality parameter, the mortality rate was 16.5% per year. When the first year of life was subdivided into 3 age categories, the mortality rate was 3.3, 4.5, and 3.1% for postnatal calves (≤14 d), preweaned calves (15–55 d), and weaned calves (56 d–1 yr), respectively. Although it was logical that these mortality rates were lower than the original, the sum of the 3 separate mortality rates was also lower than the original mortality rate. The reason was that the number of calves present in a herd and the risk of mortality are not randomly distributed over a calf's first year of life and the conditional nature of mortality rates when calculated for different age categories. Ultimately, 4 parameters to monitor calf mortality in Dutch dairy herds were chosen based on scientific value, usefulness for monitoring of trends, and comprehensibility by farmers: perinatal calf mortality risk (i.e., mortality before, during, or shortly after the moment of birth up to the moment of ear-tagging), postnatal calf mortality risk (≤14 d), preweaned calf mortality rate (15–55 d), and weaned calf mortality rate (56 d–1 yr). Slight differences in definitions of parameters can have a major effect on results, and many factors have to be taken into account when defining an important health indicator such as mortality. Our evaluation resulted in a more thorough understanding of the definitions of the selected parameters and agreement by the stakeholders to use these key indicators to monitor calf mortality.

Acute toxic effects of hydrogen peroxide, used for salmon lice treatment, on the survival of polychaetes Capitella sp. and Ophryotrocha spp.
Fang, Jinghui ; Samuelsen, Ole ; Strand, Øivind ; Jansen, H.M. - \ 2018
Aquaculture Environment Interactions 10 (2018). - ISSN 1869-215X - p. 363 - 368.
hydrogen peroxide - polychaeta - actute toxicity - mortality - lc50
The amount of hydrogen peroxide (H2O2) used in the treatment of salmon lice in Norwegian salmon farming increased from 308 tons in 2009 to 43246 tons in 2015. For 2016 and 2017, however, the consumption was reduced to 26597 and 9277 tons, respectively. The use of this compound may have negative impacts on benthic fauna underneath the fish farms and, in particular, on polychaetes, which can be found in large numbers at the bottom under fish farms where they play a key role in the turnover of organic waste from the farm. The tolerance of Capitella sp. and Ophryotrocha spp. to a 1 h exposure to H2O2 (0, 100, 200, 400, 800, 1200 and 1800 mg l-1) was evaluated. The recommended dose for treatment of the salmon is 1800 mg l-1. Following exposures, the polychaetes were reintroduced into clean sea water. Both polychaete species experienced high cumulative mortality during a 72 h post-exposure period. The mortality showed to be dose dependent, with the highest dose giving the highest mortality. The 50% lethal concentration (LC50) of Capitella sp. was significantly higher than the LC50 of Ophryotrocha spp. at the same exposure time (p < 0.05). The 50% lethal time of Capitella sp. was significantly longer than that of Ophryotrocha spp. at the same concentration (p < 0.05). The results show that 1 h exposures to H2O2 at all the tested concentrations had irreversible negative effects on both polychaete species
BeechCOSTe52 Database
Robson, Matthew T. ; Garzón, Marta Benito ; Miranda, Ricardo Alia ; Bogdan, Saša ; Borovics, Attila ; Božič, Gregor ; Brendel, Oliver ; Clark, Jo ; Vries, S.M.G. de - \ 2018
University of Helsinki
genetic trial - European beech - tree height - leaf phenology - mortality - provenance test
The BeechCOSTe52 includes phenotypic trait measurements from individual trees measured in an international network of provenance tests compiled by the COST Action E52 (2006 – 2010). It comprises 39 trial sites and 217 provenances covering the distribution of European beech (Fagus sylvatica L.). The BeechCOSTe52 database provides individual tree phenotypic measurements of height, diameter at breast height, basal diameter, mortality, spring and autumn leaf phenology.
The strength of the multivariable associations of major risk factors predicting coronary heart disease mortality is homogeneous across different areas of the Seven Countries Study during 50-year follow-up
Menotti, Alessandro ; Puddu, Paolo Emilio ; Adachi, Hisashi ; Kafatos, Anthony ; Tolonen, Hanna ; Kromhout, Daan - \ 2018
Acta Cardiologica 73 (2018)2. - ISSN 0001-5385 - p. 148 - 154.
coefficients - Coronary heart disease - hazard ratios - homogeneity - mortality - prediction - risk factors

Objectives: To compare the magnitude of multivariable coefficients and hazard ratios of four cardiovascular risk factors across five worldwide regions of the Seven Countries Study in predicting 50-year coronary deaths. Material and methods: A total of 13 cohorts of middle-aged men at entry (40–59 years old) were enrolled in the mid-1900s from five relatively homogeneous groups of cohorts (areas): USA, Finland and Zutphen – the Netherlands, Italy and Greece, Serbia, Japan for a total of 10,368 middle-aged men. The major risk factors measured at baseline were age, number of cigarettes smoked, systolic blood pressure and serum cholesterol. Cox proportional hazards models were solved for 50-year (45 years for Serbia) deaths from coronary heart disease (CHD), and the multivariable coefficients were compared for heterogeneity. Results: The highest levels of risk factors and CHD death rates were found in Finland and Zutphen – the Netherlands and the lowest in Japan. All four risk factors were predictive for long-term CHD mortality in all regions, except serum cholesterol in Japan where the mean levels and CHD events were lowest. Tests of heterogeneity of coefficients for single risk factors in predicting CHD mortality were non-significant across the five areas. The same analyses for the first 25 years of follow-up produced similar findings. Conclusions: The strength of the multivariable associations of four major traditional CHD risk factors with long-term CHD mortality appears to be relatively homogeneous across areas, pending needed further evidence.

Abiotic and biotic drivers of biomass change in a Neotropical forest
Sande, M.T. van der; Peña-Claros, M. ; Ascarrunz, N. ; Arets, E.J.M.M. ; Licona, J.C. ; Toledo, M. ; Poorter, L. - \ 2017
biomass growth - disturbance - ecosystem functioning - functional diversity - mortality - productivity - recruitment - soil conditions - species diversity
Abiotic and biotic variables and growth, recruitment and mortality for 48 1-ha plots in a moist tropical forest in Bolivia
Data from: Plant quantity affects development and survival of a gregarious insect herbivore and its endoparasitoid wasp
Fei, Minghui ; Gols, R. ; Zhu, F. ; Harvey, Jeffrey A. - \ 2016
development - group-living - herbivore - mortality - parasitiod - phenology - starvation - survival
Data for the paper of plant quantity represents a greater constraint than quality for a gregarious insect herbivore and its endoparasitoid wasp
African elephant in a cleft stick : choosing between starving or dying from thirst in arid savanna
Wato, Yussuf - \ 2016
Wageningen University. Promotor(en): Herbert Prins, co-promotor(en): Ignas Heitkonig; Frank van Langevelde. - Wageningen : Wageningen University - ISBN 9789463430005 - 126
loxodonta africana - starvation - thirst - savannas - arid zones - animal ecology - mortality - drought - loxodonta africana - uithongering - dorst - savannen - aride klimaatzones - dierecologie - mortaliteit - droogte

Elephant population studies have become important especially because of the long standing perception that high elephant densities have negative impact on vegetation and other wildlife species. Thus, in areas of high elephant density, managers attempt to re-distribute them or keep their numbers low through provision of water, translocation or culling. These approaches are thought to keep the population within the limits that can be sustained by the ecosystem, termed “the ecological carrying capacity”, a management option hinged on equilibrium theory. Equilibrium systems are considered stable, with resources and the animals that depend on them being at balance with each other. This stability is rarely the case in tropical savannas where the rule appears to be “a flux of nature” rather than “a balance of nature”.

Tropical savannas, where over half of the African elephant live, are prone to constant environmental fluctuations, especially prolonged droughts, and hence there is a growing understanding that populations of wildlife species and their communities are rarely at equilibrium. Therefore, it is critical to understand how the constant environmental flux in this system affects wildlife populations and the implication for their management. In this thesis, the central focus is to investigate the role of drought occurrences on elephant population dynamics in tropical savannas. To address this question, it is important to have a good understanding of the historical changes of elephant population in relation to drought events and the ecology of elephant in semi-arid savannas - their distribution and density, their movements and behaviour. For the historical data, I analysed the best existing long-term data in Africa of wild elephant population that has been consistently monitored for over 40 years where life histories of over 3000 wild individual elephant are known, at Amboseli National Park in Kenya. In addition, I also analysed geo-referenced elephant mortality data collected daily for 10 years from Tsavo Conservation Area. Further, I analysed 2 years data from 8 GPS collared African elephant to investigate their movement response to seasonal water and forage distribution in Tsavo Ecosystem.

First, I investigated the temporal effects of drought duration (number of consecutive dry months) and intensity (amount of rainfall) on elephant population structure in Amboseli National Park, Kenya. The result corroborates findings from past studies that calves (<2years) are more susceptible to drought caused mortality and the risk of dying decreased with age. A new finding in this study reveals that the effect of drought induced mortality for the adult elephant is sex and age dependent, with males older than 25 years being less likely to die as compared to females of the same age. This new result is because of the resolution of analysis in this study which focused on the length and severity of drought as opposed to past studies that restricted their analysis to seasonal and inter-annual differences in rainfall pattern. As they grow older and sexually mature, the foraging range of male elephant increase and they begin to take more risks and disperse to unfamiliar habitats to seek for quality forage and mates. Generally, foraging strategies between sexes in many species are more pronounced during periods of food scarcity, and the driving force in the differences appears to be driven by energy need requirements, reproductive status of an individual, body sizes and the social context, all of which differ between sexes.

In the next study, I investigated the spatial pattern of elephant mortality in relation to drought occurrences in Tsavo National Park using MaxEnt. The results shows that elephant carcasses were aggregated and elephant mortality was negatively correlated with four months cumulative precipitation prior to death, forage availability and distance to water, while local elephant density showed a positive correlation. This finding rules out dehydration as the cause of elephant mortality in Tsavo as the river where the carcasses were aggregated is perennial. Furthermore, forage availability was low close to water sources and did not show a significant difference close to or further away from the river despite high elephant density around the river. Hence, these elephant mortalities may have occurred as a result of starvation.

I went further to focus on two main limiting resources for elephants, namely forage and water, and their effect on elephant-habitat utilization in semi-arid savannas. I first investigated how water source distribution affect elephants’ seasonal movement patterns. Results indicate that male elephant moved maximally 20 km away from the nearest water source in the dry season while the female elephant foraged to a maximum of about 10 km and only moved further than this distances in the wet season. The strong directionality of elephant movement from a distance of 15km towards water sources (rho > 0.5) as they re-visited their watering source in the dry season suggest that elephant have information on location of the water sources.

Next, I investigated the factors that determine selection of a foraging site for elephant with a focus on forage nutrients or biomass. Because of their large body size, it is thought that elephant can survive on a less nutritious but high biomass of forage. The results from this study shows that elephant selected foraging site based on forage biomass in dry seasons, whereas they selected areas with higher nutrients in the wet season. Moreover, females selected sites with a higher forage biomass as compared to males. This result may be explained by the difference in social organisation and foraging strategies between the sexes. In the previous studies on human-elephant conflict, for instance, male elephant raided crops more than the mixed herd, perhaps to seek for high quality forage.

Together, the four studies in this thesis strongly suggest that elephant starve to death in prolonged drought contrary to the past studies that reported that adult elephant are less affected by drought. Even though prolonged droughts usually result in higher elephant mortalities, the resilience of semi-arid savannas may perhaps be as a result of these deaths that release the system from high browsing pressure and give it a window to regenerate. If that is the case, then drought induced elephant mortality may be a better way to regulate elephant numbers than culling. This finding strongly suggests that semi-arid savannas may in fact be a non-equilibrium system sustained by growth and crashes of herbivore populations. Maintaining the system as natural as possible may therefore keep elephant populations in savannas sustained for posterity. The modern day park managers have daunting challenges such as mass elephant deaths in drought, increased human-wildlife conflicts or changes in wildlife use of the landscape which may all be symptoms of wrong management interventions taken in the past or negative impacts of anthropogenic activities that have tipped the natural functioning of a non-equilibrium system. Therefore, park managers should undergo regular trainings on new conservation techniques and they should apply evidence-based science to make informed long term decision.

In ovo testosterone treatment reduces long-term survival of female pigeons : a preliminary analysis after nine years of monitoring
Matson, K.D. ; Riedstra, B. ; Tieleman, B.I. - \ 2016
Journal of Animal Physiology and Animal Nutrition 100 (2016)6. - ISSN 0931-2439 - p. 1031 - 1036.
ageing - bird - egg - hormone - maternal effect - mortality

Early exposure to steroid hormones, as in the case of an avian embryo exposed yolk testosterone, can impact the biology of an individual in different ways over the course of its life. While many early-life effects of yolk testosterone have been documented, later-life effects remain poorly studied. We followed a cohort of twenty captive pigeons hatched in 2005. Half of these birds came from eggs with experimentally increased concentrations of testosterone; half came from control eggs. Preliminary results suggest non-random mortality during the birds’ first nine years of life. Hitherto, all males have survived, and control females have survived better than testosterone-treated ones. Despite inherent challenges, studies of later-life consequences of early-life exposure in longer-lived species can offer new perspectives that are precluded by studies of immediate outcomes or shorter-lived species.

Dietary protein, blood pressure and mortality : the value of repeated measurements
Tielemans, S.M.A.J. - \ 2016
Wageningen University. Promotor(en): Marianne Geleijnse; Daan Kromhout, co-promotor(en): Hendriek Boshuizen. - Wageningen : Wageningen University - ISBN 9789462577916 - 169
cardiovascular diseases - blood pressure - dietary protein - mortality - cardiovascular disorders - hypertension - urea - meta-analysis - antihypertensive agents - plant protein - animal protein - hart- en vaatziekten - bloeddruk - voedingseiwit - mortaliteit - hart- en vaatstoornissen - hypertensie - ureum - meta-analyse - antihypertensiva - plantaardig eiwit - dierlijk eiwit

Cardiovascular diseases (CVD) are the main cause of death worldwide. In 2012, about 17.5 million people died from CVD, accounting for 30% of all deaths. High blood pressure (BP) is a major cardiovascular risk factor, which was responsible for 10.4 million deaths in 2013. Diet and lifestyle play an important role in the etiology of hypertension. Maintenance of a desirable body weight, physical activity, and low intake of alcohol and salt are well-known measures to avoid high BP. Whether dietary protein, or more specifically plant and animal protein, could contribute to maintaining a healthy BP is less clear. The association between BP and CVD mortality has been extensively investigated. BP in prospective studies can be analyzed using different approaches, such as single BP (measured at one moment in time), single BP adjusted for regression dilution, average BP, and trajectories of BP. It is not yet clear which of these approaches is to be preferred for CVD risk prediction.

This thesis is centered on BP as a major cardiovascular risk factor. In the first part (Chapter 2, 3 and 4), the relation of dietary protein intake with BP level and change was examined. In the second part (Chapter 5 and 6), various approaches for analyzing repeated BP measurements were compared in relation to CVD and all‑cause mortality risk. The final chapter discusses the main findings and their implications.

Chapter 2 describes the association of 24-h urinary urea excretion, as a biomarker of total protein intake, with 9-year incidence of hypertension. We analyzed data of ~4000 men and women aged 28–75 years, who participated in the Prevention of Renal and Vascular Endstage Disease (PREVEND) study, a prospective cohort study. BP was measured four times during 1997–2009 and participants were followed for hypertension incidence, defined as BP ≥140/90mmHg or use of antihypertensive medication. Urea excretion was assessed in two consecutive 24-h urine collections at baseline and approximately 4 years later, from which total protein intake was estimated. Protein intake based on 24-h urinary urea excretion was not associated with incident hypertension.

Chapter 3 presents findings for long-term total, animal and plant protein intake in relation to 5‑year BP change. Analyses were based on 702 observations of 272 men who participated in the Zutphen Elderly Study. Participants did not use antihypertensive medication and were initially free of CVD. Physical and dietary examinations were performed in 1985, 1990, 1995, and 2000. BP was measured twice at each examination and protein intake was assessed using the cross-check dietary history method. The upper tertiles of plant protein intake were associated with a mean 5‑year change in systolic BP of ‑2.9 mmHg (95% CI: ‑5.6, ‑0.2), compared with the bottom tertile. Total and animal protein intake was not associated with BP.

Chapter 4 describes a meta‑analysis of 12 observational studies and 17 randomized controlled trials (RCTs) of dietary protein, including animal and plant protein, in relation to BP. Protein intake in prospective cohort studies was not associated with incident hypertension. For RCTs that used carbohydrate as a control treatment, the pooled BP effect was ‑2.1 mmHg systolic (95% CI: ‑2.9, ‑1.4) for a weighted mean contrast in protein intake of 41 grams per day. There was no differential effect of animal and plant protein on BP.

Chapter 5 describes repeated BP measures and their association with CVD and all‑cause mortality and life years lost in two prospective and nearly extinct cohorts of middle-aged men, the Minnesota Business and Professional Men Study (n=261) and the Zutphen Study (n=632). BP was measured annually during 1947–1957 in Minnesota and 1960–1970 in Zutphen. After 10 years of BP measurements, men were followed until death on average 20 years later. Each 25-mmHg increase in average SBP was associated with a 49% to 72% greater CVD mortality risk, 34% to 46% greater all-cause mortality risk and 3 to 4 life years lost. Four systolic BP trajectories were identified, in which mean systolic BP increased by 5 to 49 mmHg in Minnesota and 5 to 20 mmHg in Zutphen between age 50 and 60. In Zutphen, a 2-times greater CVD and all-cause mortality risk and 4 life years lost were observed when comparing trajectories. In Minnesota, associations were twice as strong. BP trajectories were the strongest predictors of CVD mortality and life years lost in Minnesota men, whereas in Zutphen men, the average BP was superior to other measures.

Chapter 6 presents findings for average BP and BP trajectories in relation to CVD and all-cause mortality, taking into account antihypertensive medication. A total of 762 participants aged ≥50 years of the Rancho Bernardo Study were examined five times from 1984 to 2002 and monitored for cause‑specific mortality from 2002 to 2013. Each 20‑mmHg increment in average systolic BP was associated with 35% greater CVD mortality and 25% greater all-cause mortality risk. We identified four trajectories for systolic BP for which BP increases ranged from 5 to 12 mmHg between age 60 and 70. In individuals who belonged to the higher trajectories, 2‑3 times greater CVD mortality and 1.5-times greater all-cause mortality risks were observed, compared to those who belonged to the lowest trajectory. Long-term systolic BP trajectories and average systolic BP were both significant predictors of CVD and all-cause mortality. The associations were not modified by antihypertensive medication.

As described in Chapter 7, various approaches were used to study the relation between protein intake and BP. Findings from individual studies and a meta-analysis suggest that dietary protein per se does not affect BP within the range of intake generally consumed in the Netherlands. Replacing carbohydrates by protein, however, has a beneficial effect on BP.

Moreover, this thesis showed that BP trajectories are not superior to average BP in predicting CVD and all-cause mortality. A few repeated BP measurements, e.g. three or four, are likely to be sufficient for obtaining a reliable average BP and had a similar predictive value for mortality compared to BP trajectories. Therefore, average BP can be considered the most practical tool for estimating mortality risk.

Omvang en overleving van schubvis bijvangst in fuikenvisserij nabij kunstwerken
Griffioen, A.B. ; Keeken, O.A. van; Chen, C. ; Blom, E. ; Schram, E. ; Graaf, M. de; Winter, Hendrik V. - \ 2016
IMARES (Rapport / IMARES C140/15) - 53 p.
visserij - bijvangst - vissen - schade - dierenwelzijn - mortaliteit - fisheries - bycatch - fishes - damage - animal welfare - mortality
Deze rapportage geeft een schatting van de omvang van de bijvangst in de beroepsvisserij nabij kunstwerken op basis van fuikvangsten en diverse interviews. Daarnaast is er een experiment uitgevoerd waarbij er gekeken is naar de overleving van schubvis nadat zij in fuiken hebben gezeten. Hierbij zijn de baars en blankvoorn gebruikt om de overleving te testen in relatie tot de volgende variabelen: aanwezigheid aal: geen (0 stuks), weinig aal (7 stuks) en veel aal (50 stuks), staduur van de fuik: 3, 6 of 9 dagen en dichtheid van vis in een fuik: 60 stuks tegenover 240 stuks.
Genetische monitoring van de Nederlandse otterpopulatie : ontwikkeling van populatieomvang en genetische status 2014/2015
Kuiters, A.T. ; Groot, G.A. de; Lammertsma, D.R. ; Jansman, H.A.H. ; Bovenschen, J. - \ 2016
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 62) - 30 p.
lutra lutra - otters - populatiegenetica - inteelt - mortaliteit - monitoring - nederland - population genetics - inbreeding - mortality - netherlands
Jaarlijks wordt de Nederlandse otterpopulatie genetisch gemonitord in opdracht van het Ministerie van
Economische Zaken. Daarmee wordt een vinger aan de pols gehouden wat betreft de ontwikkeling van de
genetische status van de populatie. Deze vorm van monitoring, waarbij gebruik wordt gemaakt van DNA
geïsoleerd uit uitwerpselen en doodvondsten, maakt het tevens mogelijk veranderingen in de ruimtelijke
verspreiding en de populatieomvang te volgen. De monitoringsronde van 2014/2015 laat zien dat de
populatie verder is gegroeid naar ca. 160 individuen. Op populatieniveau lijkt geen verder verlies aan
genetische variatie te zijn opgetreden. De genetische variatie binnen individuen is evenmin verder
afgenomen in tegenstelling tot voorafgaande jaren. Onderdeel van deze monitoring is ook autopsie van dode
otters, waarbij wordt gekeken naar de doodsoorzaak en de belangrijkste lichaamskenmerken. Verkeer is
verreweg de belangrijkste doodsoorzaak. Locaties waar otters worden doodgereden, worden geregistreerd
en bijgehouden in een database. Deze informatie is belangrijk voor het veiliger maken van knelpuntlocaties
om zo het aantal verkeersslachtoffers te beperken. Het aantal verkeersslachtoffers neemt nog ieder jaar toe,
waarbij de toename evenredig is aan de toename in de populatieomvang
Er valt veel te leren van rotte kadavers : Raadselachtige ' mini-massastranding' bruinvissen
Leopold, M.F. ; Hesse, E. ; Mielke, L. ; Begeman, L. ; Hiemstra, S. - \ 2015
Zoogdier 26 (2015)2. - ISSN 0925-1006 - p. 4 - 6.
marine mammals - fauna - mortality - marine areas - inventories - north sea
In mei 2013 spoelden bij Camperduin vijf bruinvissen tegelijkertijd aan: vier grote dieren en een voldragen foetus. De vier grote bruinvissen waren allemaal erg rot, maar waren op het moment van hun dood in uitstekende voedingsconditie. Ze hadden zich volgegeten met zandspieringen en vlak voor de dood is voedsel uitgespuwd. Pathologisch en voedsel-ecologisch onderzoek komen tot dezelfde - voorzichtige - conclusie: deze dieren zijn als groep verdronken.
Specific characteristics of the aviary housing system affect plumage condition, mortality and production in laying hens
Heerkens, J.L.T. ; Delezie, Evelyne ; Kempen, Ine ; Zoons, Johan ; Ampe, Bart ; Rodenburg, T.B. ; Tuyttens, F.A.M. - \ 2015
Poultry Science 94 (2015)9. - ISSN 0032-5791 - p. 2008 - 2017.
aviary - feather pecking - housing system - mortality - red mite

Feather pecking and high mortality levels are significant welfare problems in non-cage housing systems for laying hens. The aim of this study was to identify husbandry-related risk factors for feather damage, mortality, and egg laying performance in laying hens housed in the multi-tier non-cage housing systems known as aviaries. Factors tested included type of system flooring, degree of red mite infestation, and access to free-range areas. Information on housing characteristics, management, and performance in Belgian aviaries (N = 47 flocks) were obtained from a questionnaire, farm records, and farm visits. Plumage condition and pecking wounds were scored in 50 randomly selected 60-week-old hens per flock. Associations between plumage condition, wounds, performance, mortality, and possible risk factors were investigated using a linear model with a stepwise model selection procedure. Many flocks exhibited a poor plumage condition and a high prevalence of wounds, with considerable variation between flocks. Better plumage condition was found in wire mesh aviaries (P <0.001), in aviaries with no red mite infestation (P = 0.004), and in free-range systems (P = 0.011) compared to plastic slatted aviaries, in houses with red mite infestations, and those without a free-range area. Furthermore, hens in aviaries with wire mesh flooring had fewer wounds on the back (P = 0.006) and vent (P = 0.009), reduced mortality (P = 0.003), and a better laying performance (P = 0.013) as compared to hens in aviaries with plastic slatted flooring. Flocks with better feather cover had lower levels of mortality (P <0.001). Red mite infestations were more common in plastic slatted aviaries (P = 0.043). Other risk factors associated with plumage condition were genotype, number of diet changes, and the presence of nest perches. Wire mesh flooring in particular seems to have several health, welfare, and performance benefits in comparison to plastic slats, possibly related to decreased feather pecking, better hygiene, and fewer red mite infestations. This suggests that adjustments to the aviary housing design may further improve laying hen welfare and performance.

Dietary patterns, biomarkers of atherosclerosis, cardiovascular and all-cause mortality
Sijtsma, F.P.C. - \ 2015
Wageningen University. Promotor(en): Daan Kromhout; D.R. Jacobs, co-promotor(en): Sabita Soedamah-Muthu. - Wageningen : Wageningen University - ISBN 9789462575493 - 207
dieet - hart- en vaatziekten - atherosclerose - prognostische merkers - ziektemerkers - mortaliteit - classificatiesystemen - epidemiologie - longitudinaal onderzoek - diet - cardiovascular diseases - atherosclerosis - prognostic markers - disease markers - mortality - classification systems - epidemiology - longitudinal studies

Summary belonging to the thesis entitled ‘Dietary patterns, biomarkers of atherosclerosis, cardiovascular and all-cause mortality’

The long history of epidemiologic studies on diet and cardiovascular disease (CVD) has traditionally relied on analysis of specific nutrients or foods. Dietary patterns are multiple dietary components operationalized as a single exposure; they reflect the entire diet. In general, two methods are used to define dietary patterns: 1) theoretically, or a priori, defined dietary scores and 2) empirically, or a posteriori, derived dietary patterns. A priori dietary scores were developed to assess diet quality based on adherence to dietary patterns or recommendations. An example of an ‘a posteriori’ approach is factor analysis (e.g. principal components analysis (PCA)). Factor analysis reduces data into patterns based upon intercorrelations between nutrients or foods. The aim of this thesis was to create, examine and compare several dietary patterns and indices and assess these in relation to both early stage markers of CVD (markers of endothelial function and oxidative stress) and to mortality from CVD and all-causes.

In chapter 2 we described the creation of the A Priori Diet Quality Score, representing overall diet quality in the Coronary Artery Risk Development in Young Adults (CARDIA) study. The CARDIA study included 5115 black and white men and women, aged 18-30 at baseline (1985-86). Diet was assessed diet at baseline, year 7(1992-93) and 20 (2005-06) examinations. The A Priori Diet Quality Score summed 46 food groups rated by investigators as positive or negative on the basis of hypothesized health effects. In 2652 participants with 3 diet assessments, the mean (±SD) A Priori Diet Quality Score increased from 64.1± 13.0 at year 0 to 71.1 ± 12.6 at year 20, which was primarily attributable to increased age. However, the secular trend, which was estimated from differences of dietary quality scores across time at a fixed age (age matched time trend), decreased. The diet score was higher in whites than in blacks and in women than in men and increased with education, but demographic gaps in the score narrowed over 20 y. Consumption of positively rated food groups tended to increase and negatively rated food groups tended to decrease, and were similar in direction across demographic groups.

In chapter 3 we used the ‘A Priori Diet Quality Score’ and two dietary patterns derived using principal components analysis (PCA) the ‘Fruit and Vegetables’ dietary pattern and the ‘Meat’ dietary pattern in the CARDIA study. We studied prospective associations of the ‘A Priori Diet Quality Score’, the ‘Fruit and Vegetables’ dietary pattern and the ‘Meat’ dietary pattern with cellular adhesion molecules (CAMs). The ‘Fruit and Vegetables’ dietary pattern was characterized by high intakes of fruit, vegetables, and whole grains and the ‘Meat’ dietary pattern by high intakes of red meat, refined grain, and butter. The ‘A Priori Diet Quality Score’ was related to all CAMs. The ‘Fruit and Vegetables’ dietary pattern was related to E-selectin and sICAM-1 but not to P-selectin and VCAM. The ‘Meat’ dietary pattern was related to all CAMs except VCAM. Strongest associations were for the ‘Meat’ dietary pattern with E-selectin (effect size 28% of an SD (+3.9/13.7 ng/mL)) and P-selectin (effect size 37% of an SD (+4.1/11.2 ng/mL)) and the ‘A Priori Diet Quality Score’ with sICAM-1 (effect size 34% of an SD (-15.1/44.7 ng/mL)) and VCAM (effect size of 26% of an SD (-45.1/170.3 ng/mL)).

Chapter 4 described prospective associations of the A Priori Diet Quality Score, ‘Fruit and Vegetables’ dietary pattern and ‘Meat’ dietary pattern and a plasma biomarker of lipid peroxidation, F2-isoprostanes also in the CARDIA study. We estimated associations between each dietary pattern and plasma F2-isoprostanes cross-sectionally (at year 20, n=2736) and prospectively (year 0/7 average diet and year 15/20 average F2-isoprostanes, n=2718). In the cross-sectional analysis, the A Priori Diet Quality Score and the ‘Fruit and Vegetables’ dietary pattern were inversely, and the ‘Meat’ dietary pattern was positively, associated with F2-isoprostanes (all p values <0.001). These associations were also statistically significant in prospective analysis.

In chapter 5 we described a food classification system derived from the Food-based Dietary Guidelines in the Netherlands that can be used to systematically and objectively classify foods in relation to their effects on health. Classification criteria for each food group were developed based on presumed positive, neutral or negative effects on chronic diseases of five nutrients: four that likely increase (saturated fatty acids, mono-trans unsaturated fatty acids, sodium, and added sugar) and one that likely decreases (dietary fiber) the risk of chronic diseases. This classification system also provided a framework to create food-based dietary scores for epidemiologic research on diet and chronic disease relationships.

Chapter 6 describes the creation of two dietary scores the ‘Dutch Healthy Nutrient and Food Score’ and the ‘Dutch Undesirable Nutrient and Food Score’ based on the food classification system described in chapter 5 in the Alpha Omega Trial. The Alpha Omega Trial is a randomized controlled trial; however the current analyses were done from an observational prospective cohort perspective (with adjustment for intervention groups). We included 4307 cardiac patients aged 60-80 years and monitored mortality for 10 years. Patients in the highest quintile of the ‘Dutch Healthy Nutrient and Food Score’ had 30% (HR 0.70; 95% CI 0.55-0.91) lower CVD and 32% (HR 0.68; 95%CI 0.47-0.99) lower all-cause mortality risk compared to patients in the first quintile. The ‘Dutch Undesirable Nutrient and Food Score’ was unrelated to both CVD and all-cause mortality.

In Chapter 7 we also created a ‘Dutch Healthy Nutrient and Food Score’ and a ‘Dutch Undesirable Nutrient and Food Score’ in the Zutphen Elderly Study. We assessed the association of these scores with 25 year CVD and all-cause mortality and life-years gained. We divided the men (age 65-84 years) into those with (n=210) and without (n=616) cardiovascular-metabolic diseases at baseline in 1985. During a median follow-up of 10.6 years (IQR 5.8-15.9) 806 participants died, of whom 359 from CVD. Diet scores did not predict death in all men. Among men with cardiovascular-metabolic diseases, ‘Dutch Healthy Nutrient and Food Score’ was associated with lower CVD (HR: 0.57; 95%CI: 0.35-0.93) and all-cause mortality risk (HR: 0.64; 95% CI: 0.44-0.94) comparing highest vs. lowest tertiles of the score. Men with cardiovascular-metabolic diseases in the highest vs. lowest tertile of the ‘Dutch Healthy Nutrient and Food Score’ lived 2.5 year longer. The ‘Dutch Healthy Nutrient and Food Score’ was not associated with CVD and all-cause mortality in men without cardiovascular-metabolic diseases. The ‘Dutch Undesirable Nutrient and Food Score’ was not associated with any of the outcomes.

In Chapter 8 we summarized the main findings of this thesis and reflected on some methodological considerations. First, we discussed the different approaches to derive dietary scores and patterns and the advantages and disadvantages of these methods. Second, we reflected on important aspects for creating a priori dietary scores and on further research. Finally, the general conclusions and implications were presented.

From the results presented in this thesis we conclude that adherence to a healthy diet is inversely associated with early stage markers of CVD (markers of endothelial function and oxidative stress), CVD and all-cause mortality. In summary, a healthy diet consists of plenty of vegetables and fruit, legumes, whole grains, nuts and seeds, moderate intake of fish/poultry/lean meats and low fat dairy, and limited intake of processed meats, refined grains, sugar sweetened beverages, ready meals and snacks. However, this thesis also showed that a high quality dietary pattern can be achieved in several different ways, and may differ among populations.

The impact of dietary fibers on dendritic cell responses in vitro is dependent on the differential effects of the fibers on intestinal epithelial cells
Bermudez-Brito, M. ; Sahasrabudhe, N.M. ; Rösch, C. ; Schols, H.A. ; Faas, M.M. ; Vos, P. de - \ 2015
Molecular Nutrition & Food Research 59 (2015)4. - ISSN 1613-4125 - p. 698 - 710.
immune function - receptor 2 - health - homeostasis - modulation - mortality - polysaccharides - activation - mechanisms - prebiotics
Scope In the present study, the direct interaction of commonly consumed fibers with epithelial or dendritic cells (DCs) was studied. Methods and results The fibers were characterized for their sugar composition and chain length profile. When in direct contact, fibers activate DCs only mildly. This was different when DCs and fibers were co-cultured together with supernatants from human epithelial cells (Caco spent medium). Caco spent medium enhanced the production of IL-12, IL-1Ra, IL-6, IL-8, TNF-a, MCP-1 (monocyte chemotactic protein), and MIP-1a but this was strongly attenuated by the dietary fibers. This attenuating effect on proinflammatory cytokines was dependent on the interaction of the fibers with Toll-like receptors as it was reduced by Pepinh-myd88. The interaction of galacto-oligosaccharides, chicory inulin, wheat arabinoxylan, barley ß-glucan with epithelial cells and DCs led to changes in the production of the Th1 cytokines in autologous T cells, while chicory inulin, and barley ß-glucan reduced the Th2 cytokine IL-6. The Treg-promoting cytokine IL-10 was induced by galacto-oligosaccharides whereas chicory inulin decreased the IL-10 production. Conclusions Our results suggest that dietary fibers can modulate the host immune system not only by the recognized mechanism of effects on microbiota but also by direct interaction with the consumer's mucosa. This modulation is dietary fiber type dependent.
Effect of atorvastatin on C-reactive protein and benefits for cardiovascular disease in patients with type 2 diabetes: analyses from the Collaborative Atorvastatin Diabetes Trial
Soedamah-Muthu, S.S. ; Livingstone, S.J. ; Charlton-Menys, V. ; Betteridge, D.J. ; Hitman, G.A. ; Neil, H.A.W. ; Bao, W. ; DeMicco, D.A. ; Preston, G.M. ; Fuller, J.H. ; Stehouwer, C.D.A. ; Schalkwijk, C.G. ; Durrington, P.N. ; Colhoun, H.M. - \ 2015
Diabetologia 58 (2015)7. - ISSN 0012-186X - p. 1494 - 1502.
placebo-controlled trial - acute coronary syndromes - cardiac outcomes trial - statin therapy - myocardial-infarction - on-treatment - follow-up - cholesterol - mortality - heart
Aims/hypothesis We investigated whether atorvastatin 10 mg daily lowered C-reactive protein (CRP) and whether the effects of atorvastatin on cardiovascular disease (CVD) varied by achieved levels of CRP and LDL-cholesterol. Methods CRP levels were measured at baseline and 1 year after randomisation to atorvastatin in 2,322 patients with type 2 diabetes (40–75 years, 69% males) in a secondary analysis of the Collaborative Atorvastatin Diabetes Study, a randomised placebo-controlled trial. We used Cox regression models to test the effects on subsequent CVD events (n¿=¿147) of CRP and LDL-cholesterol lowering at 1 year. Results After 1 year, the atorvastatin arm showed a net CRP lowering of 32% (95% CI -40%, -22%) compared with placebo. The CRP response was highly variable, with 45% of those on atorvastatin having no decrease in CRP (median [interquartile range, IQR] per cent change -9.8% [-57%, 115%]). The LDL-cholesterol response was less variable, with a median (IQR) within-person per cent change of -41% (-51%, -31%). Baseline CRP did not predict CVD over 3.8 years of follow-up (HRper SD log 0.89 [95% CI 0.75, 1.06]), whereas baseline LDL-cholesterol predicted CVD (HRper SD 1.21 [95% CI 1.02, 1.44]), as did on-treatment LDL-cholesterol. There was no significant difference in the reduction in CVD by atorvastatin, with above median (HR 0.57) or below median (HR 0.52) change in CRP or change in LDL-cholesterol (HR 0.61 vs 0.50). Conclusions/interpretation CRP was not a strong predictor of CVD. Statin efficacy did not vary with achieved CRP despite considerable variability in CRP response. The use of CRP as an indicator of efficacy of statin therapy on CVD risk in patients with type 2 diabetes is not supported by these data.
Low 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 levels are independently associated with macroalbuminuria, but not with retinopathy and macrovascular disease in type 1 diabetes: the EURODIAB prospective complications study
Engelen, L. ; Schalkwijk, C.G. ; Eussen, S.J.P.M. ; Scheijen, J.L.J.M. ; Soedamah-Muthu, S.S. ; Chaturvedi, N. ; Fuller, J.H. ; Stehouwer, C.D. - \ 2015
Cardiovascular Diabetology 14 (2015). - ISSN 1475-2840 - 9 p.
glomerular-filtration-rate - vitamin-d deficiency - microvascular complications - cardiovascular-disease - risk-factors - 1,25-dihydroxyvitamin d-3 - endothelial function - mortality - markers - determinants
Background Low circulating levels of total vitamin D [25(OH)D] and 25(OH)D3 have been associated with vascular complications in few studies on individuals with type 1 diabetes. However, these measures are affected by UV light exposure. Circulating 25(OH)D2, however, solely represents dietary intake of vitamin D2, but its association with complications of diabetes is currently unknown. We investigated the associations between 25(OH)D2 and 25(OH)D3 and the prevalence of albuminuria, retinopathy and cardiovascular disease (CVD) in individuals with type 1 diabetes. Methods We measured circulating 25(OH)D2 and 25(OH)D3 in 532 individuals (40¿±¿10 years old, 51 % men) with type 1 diabetes who participated in the EURODIAB Prospective Complications Study. Cross-sectional associations of 25(OH)D2 and 25(OH)D3 with albuminuria, retinopathy and CVD were assessed with multiple logistic regression analyses adjusted for age, sex, season, BMI, smoking, HbA1c, total-HDL-cholesterol-ratio, systolic blood pressure, antihypertensive medication, eGFR, physical activity, alcohol intake, albuminuria, retinopathy and CVD, as appropriate. Results Fully adjusted models revealed that 1 nmol/L higher 25(OH)D2 and 10 nmol/L higher 25(OH)D3 were associated with lower prevalence of macroalbuminuria with ORs (95 % CI) of 0.56 (0.43;0.74) and 0.82 (0.72;0.94), respectively. These vitamin D species were not independently associated with microalbuminuria, non-proliferative and proliferative retinopathy or CVD. Conclusions In individuals with type 1 diabetes, both higher 25(OH)D2 and 25(OH)D3 are associated with a lower prevalence of macroalbuminuria, but not of retinopathy and CVD. Prospective studies are needed to further examine the associations between 25(OH)D2 and 25(OH)D3 and the development of microvascular complications and CVD in type 1 diabetes.
Designing urban parks that ameliorate the effects of climate change
Brown, R.D. ; Vanos, J. ; Kenny, N. ; Lenzholzer, S. - \ 2015
Landscape and Urban Planning 138 (2015). - ISSN 0169-2046 - p. 118 - 131.
outdoor thermal comfort - green space - heat-stress - united-states - cool island - temperature - health - mortality - cities - environments
Many inhabitants of cities throughout the world suffer from health problems and discomfort that are caused by overheating of urban areas, and there is compelling evidence that these problems will be exacerbated by global climate change. Most cities are not designed to ameliorate these effects although it is well-known that this is possible, especially through evidence-based climate-responsive design of urban open spaces. Urban parks and green spaces have the potential to provide thermally comfortable environments and help reduce vulnerability to heat stress. However, in order for them to provide this function, parks must be designed within the context of the prevailing climate and predicted future climates. To analyze the effects of elements that alter microclimate in parks, we used human energy budget simulations. We modelled the outdoor human energy budget in a range of warm to hot climate zones and interpreted the results in terms of thermal comfort and health vulnerability. Reduction of solar radiant input with trees had the greatest effect in all test cities. Reduction in air temperature was the second-most important component, and in some climates was nearly as important as incorporating shade. We then conducted similar modelling using predicted climates for the middle of the century, emphasizing the importance of city-level efforts for park design to assist in minimizing future climate-related urban health risks. These simulations suggested that heat waves in many climates will produce outdoor environments where people will be in extreme danger of heat stress, but that appropriately designed parks can reduce the threat
Hyperdominance in Amazonian forest carbon cycling
Fauset, S. ; Arets, E.J.M.M. ; Steege, H. ter; Pena Claros, M. ; Poorter, L. ; Levis, C. ; Toledo, M. - \ 2015
Nature Communications 6 (2015). - ISSN 2041-1723
tropical forests - rain-forest - experimental drought - species composition - economics spectrum - biomass - trees - allometry - productivity - mortality
While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant’ species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ˜1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region.
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