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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Warmer and browner waters decrease fish biomass production
Dorst, Renee M. Van; Gårdmark, Anna ; Svanbäck, Richard ; Beier, Ulrika ; Weyhenmeyer, Gesa A. ; Huss, Magnus - \ 2019
Global Change Biology 25 (2019)4. - ISSN 1354-1013 - p. 1395 - 1408.
biomass production - browning - Climate change - Eurasian perch - fish - individual body grwoth - lakes - length distribution - ontogeny - warming
Climate change studies have long focused on effects of increasing temperatures,
often without considering other simultaneously occurring environmental changes, such as browning of waters. Resolving how the combination of warming and browning of aquatic ecosystems affects fish biomass production is essential for future ecosystem functioning, fisheries, and food security. In this study, we analyzed individual‐ and population‐level fish data from 52 temperate and boreal lakes in Northern Europe, covering large gradients in water temperature and color (absorbance, 420 nm). We show that fish (Eurasian perch, Perca fluviatilis) biomass production decreased with both high water temperatures and brown water color, being lowest in warm and brown lakes. However, while both high temperature and brown water decreased fish biomass production, the mechanisms behind the decrease differed: temperature affected the fish biomass production mainly through a decrease in population standing stock biomass, and through shifts in size‐ and age‐distributions toward a higher proportion of young and small individuals in warm lakes; brown water color, on the other hand, mainly influenced fish biomass production through negative effects on individual body growth and length‐at‐ age. In addition to these
findings, we observed that the effects of temperature and brown water color on
individual‐level processes varied over ontogeny. Body growth only responded positively to higher temperatures among young perch, and brown water color had a stronger negative effect on body growth of old than on young individuals. Thus, to better understand and predict future fish biomass production, it is necessary to integrate both individual‐ and population‐level responses and to acknowledge within species variation. Our results suggest that global climate change, leading to browner and warmer waters, may negatively affect fish biomass production, and this effect may be stronger than caused by increased temperature or water color alone
Does biomass growth increase in the largest trees? Flaws, fallacies and alternative analyses
Sheil, Douglas ; Eastaugh, Chris S. ; Vlam, Mart ; Zuidema, Pieter A. ; Groenendijk, Peter ; Sleen, Peter van der; Jay, Alex ; Vanclay, Jerome - \ 2017
Functional Ecology 31 (2017)3. - ISSN 0269-8463 - p. 568 - 581.
above-ground biomass - annual growth rings - artefacts - carbon dynamics - ecological fallacy - monitoring - ontogeny - repeated-measures - statistical methods and inference

The long-standing view that biomass growth in trees typically follows a rise-and-fall unimodal pattern has been challenged by studies concluding that biomass growth increases with size even among the largest stems in both closed forests and in open competition-free environments. We highlight challenges and pitfalls that influence such interpretations. The ability to observe and calibrate biomass change in large stems requires adequate data regarding these specific stems. Data checking and control procedures can bias estimates of biomass growth and generate false increases with stem size. It is important to distinguish aggregate and individual-level trends: a failure to do so results in flawed interpretations. Our assessment of biomass growth in 706 tropical forest stems indicates that individual biomass growth patterns often plateau for extended periods, with no significant difference in the number of stems indicating positive and negative trends in all but one of the 14 species. Nonetheless, when comparing aggregate growth during the most recent five years, 13 out of our 14 species indicate that biomass growth increases with size even among the largest sizes. Thus, individual and aggregate patterns of biomass growth with size are distinct. Claims concerning general biomass growth patterns for large trees remain unconvincing. We suggest how future studies can improve our knowledge of growth patterns in and among large trees. A lay summary is available for this article.

Data from: Does biomass growth increase in the largest trees? Flaws, fallacies and alternative analyses
Sheil, Douglas ; Eastaugh, Chris S. ; Vlam, M. ; Zuidema, P.A. ; Groenendijk, P. ; Sleen, J.P. van der; Vanclay, Jerome - \ 2016
annual-growth-rings - artefacts - aboveground-biomass - carbon-dynamics - ecological-fallacy - monitoring - ontogeny - statistical-methods and inference
The long-standing view that biomass growth in trees typically follows a rise-and-fall unimodal pattern has been challenged by studies concluding that biomass growth increases with size even among the largest stems in both closed forests and in open competition-free environments. We highlight challenges and pitfalls that influence such interpretations. The ability to observe and calibrate biomass change in large stems requires adequate data regarding these specific stems. Data checking and control procedures can bias estimates of biomass growth and generate false increases with stem size. It is important to distinguish aggregate and individual-level trends: a failure to do so results in flawed interpretations. Our assessment of biomass growth in 706 tropical forest stems indicates that individual biomass growth patterns often plateau for extended periods, with no significant difference in the number of stems indicating positive and negative trends in all but one of the 14 species. Nonetheless, when comparing aggregate growth during the most recent five years, 13 out of our 14 species indicate that biomass growth increases with size even among the largest sizes. Thus, individual and aggregate patterns of biomass growth with size are distinct. Claims concerning general biomass growth patterns for large trees remain unconvincing. We suggest how future studies can improve our knowledge of growth patterns in and among large trees.
Adventitious root formation in Arabidopsis : underlying mechanisms and applications
Massoumi, Mehdi - \ 2016
Wageningen University. Promotor(en): Richard Visser, co-promotor(en): Geert-Jan de Klerk; Frans Krens. - Wageningen : Wageningen University - ISBN 9789462578524 - 191
arabidopsis thaliana - adventitious roots - formation - plant development - quantitative traits - etiolation - auxins - explants - molecular biology - gene expression - dna methylation - rooting - ontogeny - plant breeding - arabidopsis thaliana - adventiefwortels - formatie - plantenontwikkeling - kwantitatieve kenmerken - etiolering - auxinen - explantaten - moleculaire biologie - genexpressie - dna-methylering - beworteling - ontogenie - plantenveredeling

Adventitious root (AR) formation is indispensable in vegetative propagation and is widely used. A better understanding of the underlying mechanisms is needed to improve rooting treatments. We first established a system to study rooting in Arabidopsis, the model organism in plant biology but only occasionally used to study adventitious rooting. Inhibition of polar auxin transport reduced AR formation. The role of auxin transporter proteins (several PIN-proteins) was found to be tissue-specific. Maturation (the transition from juvenile to adult) negatively influenced AR formation. Maturation was associated with increased DNA methylation and decreased miR156 level. 5-Azacytidine, a drug that reduces DNA methylation, increased rooting. We also examined the effect of two donor plant pre-treatments, etiolation and flooding, on rooting. Both increased AR formation.

Effects of early life conditions on immunity in broilers and layers
Simon, K. - \ 2016
Wageningen University. Promotor(en): Bas Kemp, co-promotor(en): Aart Lammers. - Wageningen : Wageningen University - ISBN 9789462576711 - 188
broilers - hens - ontogeny - poultry feeding - chicken housing - immune response - antibiotics - gastrointestinal microbiota - immunology - immunity - vleeskuikens - hennen - ontogenie - pluimveevoeding - huisvesting van kippen - immuniteitsreactie - antibiotica - microbiota van het spijsverteringskanaal - immunologie - immuniteit


The course for later life immune responses is set early in life during the developmental phase of the immune system and accordingly disturbances of immune development may have long-term consequences for host health. In terms of immune activation and immune development the gut microbiota play an important role and consequently disturbances of early life microbial colonization may affect host immunity later in life. In chickens, disturbances of microbial colonization may be caused by various early life conditions which in turn may affect robustness of the chick in the long term. The aim of this thesis was to assess the effects of several early life factors including time of access to feed post hatch (immediately or 72 hours delayed), housing conditions, antibiotic treatment, and intestinal pathology on the intestinal microbiota composition, immune development, and specific antibody response later in life in chickens. Additionally, possible differences between broilers and layers were taken into account as unintentional co-selection of immunological traits may have taken place during the selection process for different production traits. Delayed access to feed and administration of antibiotics early in life led to a shift in early life microbiota composition, which seemed to be restored quite quickly in both cases. Microbiota composition in response to DSS was not investigated, but based on rodent studies was expected to be influenced. Ileal immune development, which was assessed in terms of relative cytokine and immunoglobulin mRNA expression levels was not affected by feeding strategy post hatch (early vs. delayed), but a downregulation of ileal immunoglobulin expression levels could be observed during DSS treatment. All early life factors investigated affected the specific antibody response towards an immunological challenge later in life. Interestingly, there seemed to be an interaction between immediate access to feed post hatch and immune responsiveness towards the environment, thus early feeding may influence the adaptive capacity of chickens in different environments. Regarding the differences between breeds it is interesting to note that broilers seem to have developed a more humoral oriented immune strategy, while layers seem to react in a more pro-inflammatory way. Taken together, results suggested that early life conditions may influence priming of the immune system during its developmental phase, leading to altered antibody responses later in life. Furthermore, broilers and layers seem to have developed different immune strategies. Early life conditions as well as possible differences between breeds should therefore be taken into account in future immunological studies.

Spatial heterogeneity in stomatal features during leaf elongation: an analysis using Rosa hybrida
Fanourakis, D. ; Heuvelink, E. ; Carvalho, S.M.P. - \ 2015
Functional Plant Biology 42 (2015)8. - ISSN 1445-4408 - p. 737 - 745.
relative air humidity - gas-exchange - elevated co2 - conductance - leaves - size - density - adaptation - ontogeny - growth
Within-leaf heterogeneity in stomatal traits poses a key uncertainty in determining a representative value for the whole leaf. Accounting for this heterogeneity, we studied stomatal initiation on expanding leaves and estimated stomatal conductance (gs) of mature leaves. The entire lamina was evaluated at four percentages of full leaflet elongation (FLE; leaflet length relative to its final length) in Rosa hybrida L. plants grown at 60% relative air humidity (RH), and at 100% FLE following cultivation at elevated (95%) RH. Over 80% of the stomata were initiated between 33 and 67% FLE, whereas stomatal growth mostly occurred afterwards. At 100% FLE, the heterogeneity in stomatal density was the result of uneven stomatal differentiation, while an uneven differentiation of epidermal cells contributed to this variation only at elevated RH. Noticeable within-leaf differences (up to 40%) in gs were calculated at 100% FLE. Avoiding leaflet periphery decreased this heterogeneity. Despite the large promotive effect of elevated RH on stomatal and pore dimensions, the within-leaf variation remained unaffected in all characters, besides pore aperture (and, thus, gs). The noted level of within-leaf variation in stomatal features demands a sampling scheme tailored to the leaf developmental stage, the feature per se and the evaporative demand during growth.
The fearful feather pecker : applying the principles to practice to prevent feather pecking in laying hens
Haas, E.N. de - \ 2014
Wageningen University. Promotor(en): Bas Kemp; A.G.G. Groothuis, co-promotor(en): Bas Rodenburg; Liesbeth Bolhuis. - Wageningen : Wageningen University - ISBN 9789462570429 - 285
hennen - verenpikken - bangheid - gedragsproblemen - lijnen - hormonale controle - stressreactie - ontogenie - legresultaten - dierenwelzijn - diergedrag - dierfysiologie - hens - feather pecking - fearfulness - behaviour problems - lines - hormonal control - stress response - ontogeny - laying performance - animal welfare - animal behaviour - animal physiology

Billions of laying hens are kept worldwide. Severe feather pecking (SFP) is a behaviour which occurs with a high prevalence on commercial farms. SFP, the pecking and plucking of feathers of another bird, induces pain and stress and can ultimately lead to cannibalism. Moreover, SFP can occur if a bird is unable to cope with fear and stress and is living in an inappropriate environment. SFP thus reduces the welfare of many laying hens worldwide. To prevent SFP it is essential to know the risk factors in its development. To that aim, first, two experimental studies were conducted to gain insight in the principles of SFP, and three on-farm studies were conducted to assess the risk factors of SFP under commercial conditions.


Factors which relate to SFP are high fearfulness as young and low levels of brain and peripheral serotonin (5-HT) and brain dopamine (DA). Furthermore, commercial laying hen lines can differ in SFP tendencies and associated traits indicating that SFP has a genetic component. In chapters 2 and 3, fear response as young and adult, and stress response, 5-HT and DA brain levels as adult were

compared in hens of two lines: the low mortality line (LML) selected on low levels of mortality due to cannibalism and individual performance vs. the control line (CL) which was selected on individual performance only. Hens were exposed to an Open Field (OF) test at 5 weeks of age and a Manual Restraint (MR) test at 33 weeks of age. At 33 weeks of age, levels of corticosterone (CORT) post MR and 5-HT and DA levels in four brain areas were determined. Hens of the LML were less fearful at both ages and had lower levels of DA in the arcopallium, a somatomotor area involved in fear and motor control, compared to hens of the CL. In chapter 2, it was also shown that fearful chicks had higher levels of CORT and higher activity levels as adult, compared to non-fearful chicks. Moreover,

presence of fearful animals in the group was related to average CORT levels of their pen members. Fearful hens may induce social instability in a group, and thereby affecting the stress-sensitivity of their group mates. These results indicate that groups differ in levels of fear and stress-sensitivity, and that fearfulness at a young age can lead to stress-sensitivity as adults, which create a risk for development of SFP.


In chapters 4, 5 and 6, the laying hen production chain consisting of parent stock, rearing flocks and laying flocks was studied. Risk factors for SFP could originate from previous parts in the chain. Therefore, in all on-farm studies, measurements of SFP, fearfulness, basal CORT and peripheral 5-HT system were obtained, and related to housing conditions and to previous parts in the chain. Fearfulness was assessed, on a flock level, by distance to a stationary person (SP) test and latency

of bird to approach a novel object (NO). Dekalb White (DW) and ISA brown (ISA) crosses whose pure lines differ in levels of fear, CORT, 5-HT and DA, were compared. First, parent stock (PS) flocks were studied and associations between production performance and measurements of fear, stress and 5-HT were conducted and related to group size conditions (chapter 4). Second, rearing flocks originating from PS flocks were studied throughout the rearing period (chapter 5). High levels of feather damage, CORT and 5-HT in the mothers were related to fearfulness and SFP in their offspring at flock level. Especially, a large flock size and limitation and/or disruption in litter supply affected SFP and levels of fearfulness and 5-HT (chapter 5). Finally, high levels of feather damage during the laying period were related to high SFP rearing, and high fearfulness during rearing and laying (chapter 6). These studies together aimed to determine the risk factors for the development of SFP and the resulting feather damage. The main outcomes of these studies are as follows.

Ø Parent stock flocks

DW flocks were more fearful of an SP and hens had higher levels of feather damage than in ISA flocks. ISA flocks, in turn, were more fearful of the NO and hens had higher 5-HT levels than in DW flocks. A small flock size led to higher feed conversion, mortality levels, and smothering events in ISA but not in DW flocks. These results indicate that DW and ISA PS flocks differ in levels of fear and

feather damage, and respond differently to their social environment. For both crosses, fear of an SP related to high mortality and fear of the NO related to low hen body weight, egg weight, and feed intake. High basal CORT related to low egg weight. High fear and stress levels in PS flocks may, thus, negatively affect (re)production, and thereby potentially negatively influence the developing


Ø Rearing flocks

In the DW cross, high CORT, feather damage, and 5-HT of mother hens related to high SFP and fearfulness of their rearing flocks at 1 week of age. At 5 weeks of age, a peak in both gentle feather pecking (GFP) and SFP was recorded, coinciding with a disruption in substrate availability (i.e. a temporal absence of substrate) and a limitation of substrate (i.e. limited amounts of substrate

provided) in some of the farms. Especially, ISA pullets showed higher SFP under substrate limitation and became more fearful under substrate disruption than DW pullets. ISA pullets had higher 5-HT levels than DW pullets. Only in the ISA cross, high 5-HT related to high fearfulness, specifically under substrate disruption. For both crosses, high fearfulness was related to high feather damage. Furthermore, in a level system (floor system where levels are gradually added) higher levels of SFP and feather damage were found compared to an aviary system (a tier-system with cages and litter area). These results highlight that; 1) parental effects exist in the development of fearfulness and SFP, 2) disruption and limitation in substrate availability can lead to high SFP at 5 weeks of age, 3) ISA pullets are more strongly influenced by environmental conditions than DW pullets and 4) a level housing, which coincided with a large group size, increase the risk of SFP and feather damage during rearing.

Ø Laying flocks

In our sample, 49% of the laying flocks had severe damage at 40 weeks of age, compared with 71%, 65% and 53% of the rearing flocks at 15, 10 and 5 weeks of age, respectively. High fear of a SP at rearing and high SFP at 5 weeks of age related to high levels of feather damage at lay. In a floor system and at a large flock size higher levels of feather damage were recorded than in an aviary system and at a small flock size. An adjusted management on the laying farm (i.e. aerated blocks, presence of roosters or a radio playing) reduced levels of feather damage compared to standard management. DW flocks were more fearful of the SP and NO than ISA flocks. This study showed that factors during rearing and laying contributed to feather damage at 40 weeks of age.

With the knowledge from the experimental and on-farm studies in this thesis, an assessment of the risk factors for SFP could be established. Risk factors for SFP are: high fear, stress and feather damage in DW parent stock, high fear of humans, especially for DW hens, litter disruption or limitation during rearing, large group sizes, and a floor or level system.

Transplacental transmission of BTV-8 in sheep: BTV viraemia, antibody responses and vaccine efficacy in lambs infected in utero
Sluijs, M.T.W. van der; Schroer-Joosten, D.P.H. ; Fid-Fourkour, A. ; Smit, M. ; Vrijenhoek, M.P. ; Moulin, V. ; Smit, A.J. de; Moormann, R.J.M. - \ 2013
Vaccine 31 (2013)36. - ISSN 0264-410X - p. 3726 - 3731.
transmitted bluetongue virus - culicoides-variipennis - inactivated vaccine - pregnant ewes - fetal lambs - serotype 8 - pcr assay - cattle - calves - ontogeny
Bluetongue virus (BTV) is an insect vector transmitted virus which causes an economically important disease in ruminants. BTV infection during pregnancy can result in infection of the foetus, which may lead to the birth of persistently infected or immunotolerant offspring. Since persistently infected animals continuously produce large amounts of virus they could be a source of infection for the insect vector. This could significantly influence the epidemiology of the virus and hence might require additional measures to control a BTV outbreak. Therefore, we investigated the potential of BTV-8 to induce persistent infection or immunotolerance in lambs in an experimental setting. Infection of eighteen 70-75 days pregnant ewes with wild type BTV-8 led to the birth of 25 out of 44 BTV RNA positive lambs (foetal infected, FI). All 23 FI lambs born alive also had anti BTV antibodies at birth; infectious virus could be recovered from 5 out of 25 FI lambs. Viral RNA loads decreased rapidly after birth; 19 out of 20 FI lambs that remained in the experiment until week 14 after birth, were RNA negative at that time. Since persistence of BTV-8 infection could not be demonstrated, we investigated whether foetal infection had an effect on protection against a field virus infection and on efficacy of vaccination. To this end, 5 FI lambs and 5 foetal non-infected (FNI) lambs were vaccinated with the inactivated Bovilis(®) BTV-8 vaccine, five months after birth. Three weeks after the vaccination, all lambs were infected with wild type BTV-8. The foetal infection did not interfere with vaccination efficacy. In contrast, foetal BTV-8 infection induced an immune response which afforded protection against BTV challenge comparable to the level of protection induced by vaccination.
Swimming Physiology of Fish: Towards Using Exercise to Farm a Fit Fish in Sustainable Aquaculture
Palstra, A.P. ; Planas, J.V. - \ 2013
Heidelberg [etc.] : Springer - ISBN 9783642310485 - 429
dierfysiologie - vissen - wildbeheer - zwemmen - genomica - diergenetica - gedragswetenschappen - ontogenie - aquacultuur - animal physiology - fishes - wildlife management - swimming - genomics - animal genetics - behavioural sciences - ontogeny - aquaculture
Nutrition driven small-intestinal development and performance of weaned pigs and young broilers
Wijtten, P.J.A. - \ 2011
Wageningen University. Promotor(en): Martin Verstegen; Wouter Hendriks, co-promotor(en): H.B. Perdok. - S.l. : s.n. - ISBN 9789085859406 - 135
biggen - vleeskuikens - jonge dieren - dunne darm - ontogenie - diervoeding - voedingsstoffen - eiwitgehalte - prestatieniveau - dierlijke productie - piglets - broilers - young animals - small intestine - ontogeny - animal nutrition - nutrients - protein content - performance - animal production

The relative importance of animal husbandry and nutrition during the first weeks after weaning in pigs and after hatch in broilers has increased considerably over the past 50 years as a result of the tremendous improvement in daily body weight (BW) gain. Substantial changes in weight, architecture, and physiology of the small intestine occur early in the life of these animals. The optimal function of the small intestines is fundamental for nutrient absorption from the diet and for health. Nutrient requirement studies conducted on these animals have largely overlooked the very young animal. It is therefore logical that there are still gaps in our knowledge of the nutrition of these animals during this particular stage of life. The objective of this thesis was to improve small-intestinal development and performance of pigs after weaning and young broilers by ways of an optimal nutrient composition of the diet. In experiments with broilers, it was shown that enhanced dietary ideal protein (IP) concentrations in the starter diet increased BW gain in the starter phase and in the subsequent grower phase. Moreover, the effects of enhanced IP concentrations in the starter diet on BW gain are more marked than the effects in the grower and finisher diets. However, BW gain hardly improved in response to dietary IP increment during the first 3 d after hatch, whereas in the consecutive 3 d, BW gain improved substantially with enhanced dietary IP concentrations. This suggests that the first 3 d after hatch, from a nutritional point of view, are substantially different from the next consecutive days in the life of broiler chicks. Moreover, a 30% increase in dietary IP increased the duodenum weight between 6 and 9 d of age. Thus, in young broilers, a greater relative small-intestinal weight is associated with a greater BW gain. However, this thesis did not make a clear determination of the functional changes of the small intestine after hatch in broilers. A review of the literature showed that after weaning in pigs, the barrier function of the tight junctions of the small intestine is disturbed, and transcellular barrier function seems to improve after weaning. In the first study with pigs, the data here showed that paracellular barrier functions, as measured with orally administered lactulose, did not correlate with bacterial translocation or transcellular barrier function, as measured with horseradish peroxidase in Ussing chambers. Therefore, it was concluded that lactulose recovery in the urine of pigs after weaning is not associated with risk factors for infection. The last study with pigs showed that dietary protein with dextrose stimulates mucosal weight after weaning. However, the combination of protein with dextrose had no substantial effect on small-intestinal barrier function, whereas dietary starch with dextrose improved small-intestinal barrier function. In conclusion, optimising protein nutrition in broilers after hatch has a great potential to further improve overall broiler performance. In particular, knowledge regarding optimal nutrition during the first 3 d after hatch is still lacking. Furthermore, dietary protein is a potent stimulator for growth of the proximal small intestine in broilers and of the small-intestinal mucosa in pigs. However, mucosal mass and luminal protein are of minor importance for small-intestinal barrier function in pigs after weaning. In contrast, the luminal carbohydrate supply or energy level is important for maintaining small-intestinal barrier function.

Talking tails : quantifying the development of tail biting in pigs
Zonderland, J.J. - \ 2010
Wageningen University. Promotor(en): Bas Kemp; Leonard den Hartog, co-promotor(en): Marc Bracke; Hans Spoolder. - [S.l. : S.n. - ISBN 9789085857822 - 176
varkens - staartbijten - abnormaal gedrag - diergedrag - ontogenie - etiologie - preventie - varkensstallen - dierenwelzijn - omgevingsverrijking - pigs - tail biting - abnormal behaviour - animal behaviour - ontogeny - aetiology - prevention - pig housing - animal welfare - environmental enrichment
Tail biting is an adverse behaviour characterised by manipulation of a pig’s tail by another pig resulting in tail damage and a possible tail biting outbreak. Tail biting is a common problem in the pig husbandry causing economic losses and reduced animal welfare worldwide. To prevent tail biting, the majority of newborn piglets are tail docked, a procedure which is not only painful but generates more and more public concern. This emphasizes the need to prevent the occurrences of tail biting without having to dock a pig’s tail. So far, research focused mainly on the risk factors that can induce tail biting. However, the way a tail biting outbreak evolves in a group of pigs (the ‘aetiology’) is still poorly understood. For that reason, the main aim of this thesis was to gain more insight in the aetiology of a tail biting outbreak. This will not only enhance our understanding of the current preventive and curative treatments of tail biting, but can also generate more effective measures to prevent, predict and counteract a tail biting outbreak. Therefore, the development of tail biting behaviour and tail damage was studied in relation to preventive and curative measures, group composition and indicators for an upcoming tail biting outbreak. The results showed that the provision of twice daily a handful of long straw strongly reduced tail biting. Furthermore, this measure was also effective in counteracting an ongoing tail biting outbreak (an outbreak was defined as the first day with a minimum of one piglet with a tail wound or two piglets with bite marks in a pen), although this outbreak could not be totally eliminated. In pens without straw almost all pigs performed and received tail biting behaviour at low levels prior to a tail biting outbreak. However, considerable variation in tail biting behaviour between pigs was found. In most pens one or a few pigs could be identified as pronounced biters prior to the tail biting outbreak. Although less clear, often one or a few pigs could similarly be identified as pronounced victims. In mixed-sex pens male pigs developed tail damage most rapidly, while in single-sex pens the quickest tail damage development was found in all-female groups. These results indicate that female pigs are more likely to become biters and male pigs are more likely to become victims. More detailed study of pronounced biters and victims showed that prior to a tail biting outbreak, biters not only directed more of their biting behaviour to their penmates’ tail, but also to the enrichment device. Victims were the heavier pigs in the pen and tended to be more often male and more restless preceding an outbreak. Victims also performed more aggressive behaviour, while biters tended to receive more aggressive behaviour. Furthermore, it was found that tail posture is a predictor for tail damage. Pigs with their tail between the legs had a higher chance of tail damage 2-3 days later.
Based on the results of this research an aetiology model of a tail biting outbreak was developed. Subsequently practical suggestions were given to prevent (e.g. providing effective environmental enrichment), predict (e.g. observing the pigs’ tail posture) and counteract (e.g. removing the biter) a tail biting outbreak. This provides opportunities to omit tail docking without the negative consequence of tail biting.
Early feeding affects resistance against cold exposure in young broiler chickens
Brand, H. van den; Molenaar, R. ; Star, I. van der; Meijerhof, R. - \ 2010
Poultry Science 89 (2010)4. - ISSN 0032-5791 - p. 716 - 720.
subsequent early performance - gallus-domesticus - avian thermoregulation - energy-utilization - turkey poults - growth - responses - ontogeny - system - period
In field conditions, a fasting period of 24 to 72 h after hatch is common, which is associated with delayed gastrointestinal development and yolk utilization and retarded subsequent performance. Hardly any information is available about the influence of diet composition in the first days on later life and additionally, effects of early feeding on thermoregulatory development are also not known. The aim of this study was to investigate effects of diet composition in early fed broiler chickens on their (thermoregulatory) development. Shortly after hatch, 200 Hybro chickens (initial BW of 43.6 g) were assigned to 1 of 5 feed treatments: control, dextrose, albumen, prestarter, or prestarter plus fat. Water was available ad libitum. Measurements were done in 10 replicates of 4 chickens per treatment. At d 2 or 3, half of the chickens were exposed to 20°C for 30 min to determine resistance against cold exposure and rectal temperature was determined just before, immediately after, and 30 min after the end of this cold exposure. Thereafter, all chickens were killed to investigate body development. Chickens in both prestarter groups developed faster than in the other 3 groups, expressed by a higher BW, yolk-free body mass, heart and liver weight, and higher chick and intestine length. Between d 2 and 3, differences in these variables among chickens from both prestarter groups and other groups increased. Rectal temperature before cold exposure was higher in chickens from both prestarter groups (40.6 and 40.7°C, respectively) and decreased less (0.6 and 0.7°C, respectively) during cold exposure than in chickens from the control (39.5 and 1.2°C, respectively) and albumen group (39.8 and 2.1°C, respectively), whereas chickens from the dextrose group were in between (40.4 and 1.2°C, respectively). We conclude that early fed diet composition in broiler chickens is (besides general development) important for development of both body temperature and resistance against cold exposure, probably as a reflection of a changed metabolic rate
Morphological transitions and the genetic basis of the evolution of extraembryonic tissues in flies
Rafiqi, A.M. - \ 2008
Wageningen University. Promotor(en): Ton Bisseling, co-promotor(en): U. Schmidt-Ott. - [S.l.] : S.n. - ISBN 9789085852100 - 118
drosophila - moleculaire genetica - evolutie - genexpressie - episyrphus balteatus - genen - serosa - ontogenie - drosophila - molecular genetics - evolution - gene expression - episyrphus balteatus - genes - serosa - ontogeny
Robustness in laying hens
Star, L. - \ 2008
Wageningen University. Promotor(en): Bas Kemp; Johan van Arendonk, co-promotor(en): Henk Parmentier; Jan van der Poel. - [S.l.] : S.n. - ISBN 9789085049708 - 196
hennen - pluimvee - adequate immuniteit - humorale immuniteit - overleving - genetische factoren - milieufactoren - stressreactie - ontogenie - karakteristieken - dierveredeling - hens - poultry - immune competence - humoral immunity - survival - genetic factors - environmental factors - stress response - ontogeny - characteristics - animal breeding
The aim of the project ‘The genetics of robustness in laying hens’ was to investigate nature and regulation of robustness in laying hens under sub-optimal conditions and the possibility to increase robustness by using animal breeding without loss of production. At the start of the project, a robust animal was defined as ‘an animal under a normal physical condition that has the potential to keep functioning and take short periods to recover under varying environmental conditions’. Next, parameters or traits were selected that could give an indication of robustness, and that could be implemented into a breeding goal for robustness. The experiments described in this thesis investigated parameters of interest for robustness in laying hens, where the influence of genetic background, environmental conditions, and early-life experiences was used as framework. The first experiment aimed at genetic differences in innate (natural) humoral immune components between 12 purebred layer Lines. Levels of innate and specific immune competence depended on genotype. Within layer lines, however, innate immune competence was related with survival. The second experiment aimed at influence of, or response to, environmental conditions, i.e., climatic stress (high temperature) and microbial challenge (lipopolysaccharide). Comparable response patterns to climatic stress and microbial challenge were found within lines, but lines differed in response levels towards these stressors. The third experiment aimed at improvement of robustness by early-life experiences to climatic stress and microbial challenge. The data did not reveal improvement of robustness by early-life experiences. Results from these studies indicate that robustness mainly depends on genetic background and environmental circumstances and to a minor extent on early-life experiences. The basic elements for robustness are survival, reproduction, and responsiveness towards environmental stressors, where a robust laying hen is a hen with a high survival rate, high production level, and low responsiveness towards environmental stressors. We have established a predictive value for the level of NAb binding to KLH for survival of the laying period of laying hens. Besides, NAb have a moderate heritability, giving opportunity for selection towards this trait. Performance parameters and innate immune parameters are most likely not related and selection on innate immune parameters will probably not be on the expense of hen-day egg production. Implementation of selection for NAb into a breeding goal might, therefore, improve robustness of laying hens.
Endurance exercise differentially stimulates heart and axial muscle development in zebrafish (Danio rerio)
Meulen, T. van der; Schipper, H. ; Boogaart, J.G.M. van den; Huising, M.O. ; Kranenbarg, S. ; Leeuwen, J.L. van - \ 2006
American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 291 (2006). - ISSN 0363-6119 - p. R1040 - R1048.
rainbow-trout - teleost fish - oncorhynchus-mykiss - brachydanio-rerio - erythropoietin - fibers - growth - performance - expression - ontogeny
Mechanical load is an important factor in the differentiation of cells and tissues. To investigate the effects of increased mechanical load on development of muscle and bone, zebrafish were subjected to endurance swim training for 6 h/day for 10 wk starting at 14 days after fertilization. During the first 3 wk of training, trained fish showed transiently increased growth compared with untrained (control) fish. Increased expression of proliferating cell nuclear antigen suggests that this growth is realized in part through increased cell proliferation. Red and white axial muscle fiber diameter was not affected. Total cross-sectional area of red fibers, however, was increased. An improvement in aerobic muscle performance was supported by an increase in myoglobin expression. At the end of 10 wk of training, heart and axial muscle showed increased expression of the muscle growth factor myogenin and proliferating cell nuclear antigen, but there were major differences between cardiac and axial muscle. In axial muscle, expression of the "slow" types of myosin and troponin C was increased, together with expression of erythropoietin and myoglobin, which enhance oxygen transport, indicating a shift toward a slow aerobic phenotype. In contrast, the heart muscle shifts to a faster phenotype but does not become more aerobic. This suggests that endurance training differentially affects heart and axial muscle
Trichome dynamics and artemisinin accumulation during development and senescence of Artemisia annua leaves
Lommen, W.J.M. ; Schenk, E. ; Bouwmeester, H.J. ; Verstappen, F.W.A. - \ 2006
Planta Medica 72 (2006)4. - ISSN 0032-0943 - p. 336 - 345.
dihydroartemisinic acid - biosynthetic precursors - glandular trichomes - antimalarial-drugs - essential oil - identification - plants - ontogeny
Artemisinin is a sesquiterpene lactone endoperoxide and an important antimalarial drug produced in Artemisia annua. To unravel the diverse processes determining artemisinin yield in A. annua crops, artemisinin accumulation during the development of individual leaves was studied in two field experiments. During the life cycle of a leaf, artemisinin was always present. Quantities were low at leaf appearance and increased steadily. In leaves studied until after senescence, maximum quantities and concentrations were achieved after the leaf had turned brown. The total quantity of possible artemisinin precursors per leaf (dihydroartemisinic acid and other upstream precursors) was highest early in the leaf cycle when the leaf was still expanding. Dihydroartemisinic acid was more abundant than the other compounds and its quantity declined during leaf development whereas that of artemisinin increased. Dihydroartemisinic acid was not converted directly into artemisinin, because on a per leaf basis the decline in molar quantity of precursors in the earliest formed leaves was not compensated for by a simultaneous increase in artemisinin. Our results suggest that a (putative) intermediate such as dihydroartemisinic acid hydroperoxide temporarily may have accumulated in considerable quantities. The number of mature, capitate trichomes on the adaxial leaf side increased after leaf appearance until the end of leaf expansion, and then decreased, probably due to collapse of trichomes. Artemisinin production thus (also) occurred when trichomes were collapsing. Later formed leaves achieved higher concentrations of artemisinin than earlier formed leaves, because of a higher trichome density and a higher capacity per trichome.
Ontogeny of the common carp (Cyprinus carpio L.) immune system
Huttenhuis, B.T. - \ 2005
Wageningen University. Promotor(en): Wim van Muiswinkel; Huub Savelkoul, co-promotor(en): Jan Rombout. - Wageningen : - ISBN 9085042542 - 173
karper - cyprinus - immuunsysteem - ontogenie - genexpressie - immunostimulatie - immuniteitsreactie - immunologie - carp - cyprinus - immune system - ontogeny - gene expression - immunostimulation - immune response - immunology
Rag expression identifies B and T cell lymphopoietic tissues during the development of common carp (Cyprinus carpio)
Huttenhuis, B.T. ; Huising, M.O. ; Meulen, T. van der; Oosterhoud, C.N. van; Alvarez Sánchez, N. ; Taverne-Thiele, J.J. ; Stroband, H.W.J. ; Rombout, J.H.W.M. - \ 2005
Developmental and Comparative Immunology 29 (2005)12. - ISSN 0145-305X - p. 1033 - 1047.
trout oncorhynchus-mykiss - activating gene-1 rag1 - v(d)j recombination - developing zebrafish - class-i - thymus - thymocytes - involution - ontogeny - system
The generation of lymphoid cells during carp development was studied by analyzing expression of the recombination activating genes (rag) using in situ hybridization and real time quantitative PCR. These data were combined with immunohistochemistry using the mAb's WCL9 (cortical thymocytes) and WCI12 (B cells). Carp rag-1 and rag-2 showed 90 and 89% amino acid identity, respectively, to the corresponding zebrafish sequences. Rag-1 was first expressed in the thymus at 4 days post-fertilization (dpf), while both rag-1+/WCL9+ and rag-1¿/WCL9¿ areas were distinguished from 1 week post-fertilization (wpf), suggesting early cortex/medulla differentiation. From 6 dpf, rag-1+ cells were also present cranio-lateral of the head kidney. From 1 wpf, rag-1/rag-2 was expressed in kidney (together with immunoglobulin heavy chain expression) but not in spleen, while WCI12+ cells appeared 1 week later in both organs, suggesting B cell recombination in kidney but not in spleen. Rag-1 expression exceeded rag-2 levels in thymus and in head- and trunk-kidney of juveniles, but this ratio was reversed in head- and trunk-kidney from approximately 16 wpf onwards. Rag-1/rag-2 expression was detected in thymi of animals over 1-year-old, but in kidney only at low levels, indicating life-long new formation of putative T cells but severely reduced formation of B cells in older fish.
Epigenetics of the locomotory system in zebrafish
Meulen, T. van der - \ 2005
Wageningen University. Promotor(en): Johan van Leeuwen, co-promotor(en): Sander Kranenbarg; Henk Franssen. - Wageningen : - ISBN 9085043220 - 191
danio rerio - skeletspierstelsel - epigenetica - biologische ontwikkeling - ontogenie - merkergenen - lichaamsbeweging - biofysica - diermodellen - dierproeven - mechanische invloeden - danio rerio - musculoskeletal system - epigenetics - biological development - ontogeny - marker genes - exercise - biophysics - animal models - animal experiments - mechanical influences
Swimming and muscle structure in fish
Spierts, I.L.Y. - \ 1999
Agricultural University. Promotor(en): J.W.M. Osse; H.A. Akster; J.L. van Leeuwen. - S.l. : Spierts - ISBN 9789090127026 - 221
vis - zwemmen - beweging - kinematica - spieren - spiervezels - lichaamsafmetingen - groei - leeftijd - ontogenie - spierfysiologie - morfologie - fish - swimming - movement - kinematics - muscles - muscle fibres - body measurements - growth - age - ontogeny - muscle physiology - morphology

In this series of studies the relations between swimming behaviour of fish in general and extreme swimming responses in particular (called fast starts or escape responses) and the structure and ontogeny of the muscle system was investigated. Special attention was paid to relate functional differences between anterior and posterior parts of the axial myotomal muscles of fish to differences in their structural design. In the past considerable knowledge has been accumulated concerning the muscular system. There are however still many unsolved questions. What for example is the influence of swimming in different fish species on the ontogeny of their muscles. How is the development of the muscle system reflecting functional demands (e.g. strength of fibre, elastic properties etc.) and what is the relationship between muscle development on a molecular scale and a macro scale? These and other questions will partly be addressed in this study.

Initially the larval muscle system and its function was investigated in general as fish larvae swim in a different hydrodynamic environment, compared to adult fish, characterised by the importance of viscous forces which can not be neglected (Osse, 1990). In contrast to adults, the different muscles during the early stages of life of many fish species (e.g. Rutilus rutilus , Alburnus alburnus , Leuciscus cephalus , Clupea harengus, Clarias gariepinus ) have an aerobic metabolism (El-Fiky et al., 1987). In yolk-sac larvae of Clarias gariepinus for example, at a time when gill development is still insufficient and muscle rely for oxygen supply on diffusion through the body surface, both the superficial red muscle layer as well as the inner 'larval white' muscle mass are aerobic. The superficial red layer initially only consisted of a monolayer. At the moment the gills started to develop the superficial red layer acquired additional fibres along the horizontal septum, resulting in a double layer of red fibres at this location. The differences in metabolism between the red aerobic fibres and the white anaerobic fibres develop during the free-swimming larval stage of e.g. roach ( Rutilus rutilus ) and rainbow trout ( Salmo gairdneri ) and the adult pattern of muscle fibre type distribution emerges (Hinterleitner et al., 1987). As this development probably occurs in relation to gill development, it is thought that the red layer of yolk-sac larvae has a negligible role in swimming but an important role in respiratory (El-Fiky et al., 1987). Once the adult pattern of muscle fibre type distribution has developed the actual differences between the various muscles can be studied in great detail.

The effects of transmission of forces on the structure and function of different muscle fibre types and at different locations along the body axis were studied during swimming of adult carp ( Cyprinus carpio L.). The connection between muscle fibres and collagen fibres, myotendinous junctions (MTJs), was investigated electron-microscopically. Especially during extreme swimming movements such as escape fast-starts large forces are imposed on the muscular system and mainly on the MTJs. During these life-saving swimming movements large sarcomere strains (relative to sarcomere slack length) occurred. Muscle fibres in the tail region (together with the connective tissue) play an important role in the transmission of force produced by more anterior fibres. Posterior fibres have a longer phase of eccentric activity (active while being stretched) than the anterior fibres and will therefore develop greater forces (van Leeuwen et al., 1990; van Leeuwen, 1995). It was therefore expected that greater forces in these posterior fibres would be accompanied by stronger MTJs (a greater membrane amplification). Posterior (80% of the fork length, FL ) muscle fibres of carp indeed had much larger myotendinous surface areas than anterior fibres (40% FL ) and consequently can transmit larger forces and 'bear' larger loads during swimming. Red muscle fibres of carp had a larger membrane amplification at the MTJs than white fibres. Red fibres are active at lower tail beat frequencies (longer cycle times) than white fibres and for longer periods of time, resulting in a longer duration of the load on the junction of red fibres. Tidball and Daniel (1986) proposed that the degree of membrane amplification at MTJs not only depends on the magnitude but also on the duration of load on the junction. Curtis (1961) and Rand (1964) showed that the mechanical behaviour of cell membranes is dependent on loading time. Cells can survive a certain shear load (caused by applying either a large load for a short time or a small load for a longer time) by reducing the stress on the membrane through an amplification of the membrane area. It was therefore suggested that the larger membrane amplification at the MTJs of carp red muscle fibres may be related to the longer duration of the load on the junction in this fibre type.

Not only the MTJs were subjected to large forces during fast-starts (accompanied by large strain fluctuations). High demands will also be imposed on the muscle system itself and the series elastic elements within the sarcomere unit, such as the titin filaments (Wang et al., 1991). This may be reflected in the type and structure of the elastic elements as different isoforms of titin seem to exist (Wang et al., 1991; Granzier and Wang, 1993a,b). To help elucidate the relation between the possible occurrence of different titin isoforms and the functional properties of different fibre types, the presence of different titin isoforms in red and white anterior and posterior fibres of the axial muscles of adult carp was investigated. Titin is a striated-muscle-specific giant muscle protein that spans the distance from the Z- and M-lines of the sarcomere (Wang, 1985; Maruyama, 1986, 1994; Trinick, 1991). The elastic segment of titin in the I-band is thought to function as a molecular spring that is responsible for maintaining the central positions of the thick filaments in contracting sarcomeres and develops passive tension upon sarcomere stretch (Horowits et al., 1986; Fürst et al. 1988; Wang et al., 1991, 1993; Granzier et al., 1996).

Gel-electrophoresis of single fibres of carp revealed that the molecular mass of titin was larger in red than in white fibres. For both red and white fibres the molecular mass of titin was larger in posterior than in anterior muscle fibres. Thus depending on the fibre type and its location along the body axis different titin isoforms were expressed.

Furthermore the contribution of titin to passive tension and stiffness of red anterior and red posterior fibres was determined in micro-mechanical experiments. It appeared that more passive tension and stiffness was needed to stretch fibres with smaller titin isoforms (red anterior fibres) to a certain sarcomere length than in fibres with larger titin isoforms (red posterior fibres). Continuous swimming is the most frequently used swimming mode in adult carp and is driven by the activity of red muscle. During this type of swimming sarcomere strain is larger in red muscle fibres, which have larger titin isoforms, than in the three-dimensionally folded white muscle tissue, due to differences in distance between the sarcomere and the body axis and differences in fibre arrangement between both types. As during cyclic swimming local curvature increases from anterior to posterior the sarcomere strain is consequently larger in posterior fibres, which have larger titin isoforms. The finding that exactly those fibres that are exposed to the largest sarcomere strains during continuous swimming also possessed the largest titin isoforms led to the suggestion that titin isoform and sarcomere strain are correlated in order to minimise energy loss during cyclic loading of muscle fibres.

However, it was still unknown how large the maximum sarcomere strains actually were during the most extreme swimming responses of adult carp. Therefore a study on the kinematics and muscle dynamics of escape fast-starts of carp was conducted. Adult carp perform escape C- or S-starts, based on the typical body curvature of the fish during these movements. During the Mauthner initiated C-starts (Eaton et al., 1977; Kimmel et al., 1980) adult carp made a large angle of turn directed away from the stimulus (approximately 150°) with a high acceleration at 0.3 FL of up to 54 m s -2. The maximum sarcomere strains (both anteriorly and posterior) were approximately 27% for red fibres and approximately 16.5% for white fibres. During escape S-starts however maximum strain in anterior fibres was more than twice that of posterior fibres with an angle of turn of approximately 70°. This large anterior peak curvature enabled the fish to control the direction of escape better but with lower accelerations at 0.3 FL (approximately 40 m s -2), although little is known about the neuronal mechanisms controlling S-starts. The largest strains occurred in red anterior fibres during S-starts (39%). It was found that during continuous and intermittent swimming the largest strains (red posterior fibres, approximately 5%) were found in fibres with the largest titin isoforms. This enabled these fibres to attain large strain amplitudes with relatively low passive tensions.

It was surprising to find that in all fast-starts both red and white muscle were simultaneously active at a given longitudinal location, whereas only red muscle were active during continuous swimming. Red fibres could contribute to muscle fibre shortening at the beginning of their mechanical response for a very short period of time (before the full response was reached). This implies that red fibres hence could contribute to force generation during these extremely fast swimming modes, although little. Red and white muscle at a given longitudinal location were not necessarily active synchronously and could be uncoupled during escape S-starts. In this way mechanically sub-optimal patterns of force generation can be avoided. In both C- and S-starts both anterior and posterior muscle were active whilst lengthening at a certain moment, thus initially absorbing power which results in significant force- and performance enhancement.

Fish larval swimming on the other hand is very different from adult swimming. Small carp larvae of approximately 6.5-8 mm total length are subjected to relatively low Reynolds-regimes of approximately 200≤Re≤500 and therefore require special features to overcome effects of friction. As superficial red fibres of Cyprinid larvae are mainly used as a respiratory organ (see above), larval swimming behaviour is mainly powered by the inner 'larval white' fibres (El-Fiky et al., 1987). But how exactly are these inner 'larval white' fibres able to generate enough power to overcome these friction effects and reach velocities of over 20 bodylength s -1? As small carp larvae and adults show large differences in their swimming behaviour the sarcomere strain ranges during fast swimming of larvae were investigated, together with their size of titin. During fast swimming of carp larvae all muscle fibres showed maximum sarcomere strains of approximately 20%, whereas their titin appeared to be shorter than any titin isoform found in adult muscle. Apparently the molecular structure of titin changed in the course of ontogeny. This shorter titin isoform (requiring larger stress for the same strain) is thought to help restricting form changes of the swimming larvae and to increase the elastic contribution to the tail beat. Such molecules possibly also increase the resonant frequency of the beating tail and thereby provide the required high frequency for swimming in a relatively low Reynolds-regime.

The present study corroborates the idea that strong relations exist between the structural design of the muscular system, from micro- to macro-level, and its functions, also in diverse levels, in a fish's specific habitat. Starting at a structural level, differences in muscle function during swimming of fish can be used in an effort to explain and possibly predict morphological differences between the various muscle types and even within the same muscle type.

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