Staff Publications

Staff Publications

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

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

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

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

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Effect of IGF-1 level at weaning on subsequent luteal developement and progesterone production in primiparous sows
Han, Taehee ; Björkman, S. ; Soede, N.M. ; Oliviero, C. ; Peltoniemi, O. - \ 2019
In: Abstract book 11th European Symposium of Porcine Health Management (ESPHM). - - p. 82 - 82.
Insulin-like growth factor-1 (IGF-1) is known to be related to follicle and oocyte development in sows. Wehypothesized that a higher IGF-1 level at weaning may derive better luteal development during early pregnancyin primiparous sows. We retrospectively assigned 56 primiparous sows into high- (HI, ? 255 ng/ml, n = 14),medium- (MI, 150 – 255 ng/ml, n = 28) or low- (LI, ? 150 ng/ml, n =14) group based on their plasma IGF-1level at weaning. Follicle diameter was measured at weaning, three days after and one day after estrus withtransrectal ultrasonography. Blood sampling was performed on the same day as ultrasonography. At 21 day afterinsemination, corpus luteum (CL) size and plasma progesterone level were measured. MIXED and GLIMMIXmodels (SAS 9.4) were used for analyses. The IGF-1 level at three days after weaning and one day after estrusremained significantly different between the three groups. Follicle diameter at weaning of HI sows was largerthan that of LI sows (p = 0.02) but similar with that MI sows (3.5 ± 0.1 vs. 3.6 ± 0.1 vs. 3.8 ± 0.1 mm, for LI,MI and HI, respectively). However, further follicle development and pregnancy rate (93.3 %) were not differentbetween the groups. In pregnant sows, LI sows tended to have larger CL at day 21 (p = 0.08) compared to MIand HI sows (10.1 ± 0.2 vs. 9.9 ± 0.1 vs. 9.4 ± 0.2 mm, for LI, MI and HI, respectively). In addition,progesterone level tended to be positively correlated with CL diameter (? = 3.0 (ng/ml)/mm, p = 0.09). Thus,although post-weaning IGF-1 was not related with follicle development at ovulation, it was negatively relatedwith subsequent CL development. Subsequent studies focusing on the relationship between post-weaning IGF-1level and luteinizing hormone will be needed.
Pilot to actively restore native oyster reefs in the North Sea: comprehensive report to share lessons learned in 2018
Didderen, K. ; Lengkeek, Wouter ; Kamermans, P. ; Deden, B. ; Reuchlin-Hugenholtz, E. ; Bergsma, J.H. ; Gool, A.C.M. van; Have, T.M. van der; Sas, Hein - \ 2019
Culemborg : Bureau Waardenburg (Report / Bureau Waardenburg 19-013) - 33 p.
Recommendations for flat oyster restoration in the North Sea
Sas, Hein ; Didderen, K. ; Have, Tom van der; Kamermans, P. ; Wijngaard, K. van den; Reuchlin-Hugenholtz, E. - \ 2019
- 34 p.
Shellfish bed restoration pilots Voordelta, Netherlands : Annual report 2018
Didderen, K. ; Have, Tom van der; Bergsma, J.H. ; Jagt, H. van der; Lengkeek, Wouter ; Kamermans, P. ; Brink, A.M. van den; Maathuis, Margot ; Sas, Hein - \ 2019
Wageningen Marine Research - 68 p.
Flat oyster pilot design in North Sea offshore wind farm
Sas, Hein ; Have, T.M. van der; Kamermans, P. ; Lengkeek, Wouter - \ 2018
- 35 p.
Motivation flat oyster pilot in wind farms. Flat oyster beds provide natural hard-substrate habitat in a predominantly soft-bottom marine environment. In addition, they change environmental conditions by filtering, nutrient recycling and carbon storage. Hence, North Sea marine life, probably even including fish production, will increase when flat oyster beds are restored. Since bottom-trawling fishery is excluded in wind farms, an essential condition for flat oyster restoration is fulfilled here. Basic conditions for flat oyster growth and reproduction, such as food availability, sediment composition and sea floor stability, are also met in several wind farms off the Dutch coast. Hence, flat oyster restoration in wind farms constitutes a potential marine biodiversity enrichment opportunity. The current report provides key information on design, deployment, monitoring and final removal of a flat oyster restoration pilot in a wind farm in the Dutch part of the North Sea.
Shellfish bed restoration pilots: Voordelta The Netherlands : Annual report 2017
Sas, H. ; Kamermans, P. ; Have, T.M. van der; Christianen, M.J.A. ; Coolen, J.W.P. ; Lengkeek, W. ; Didderen, K. ; Driessen, F. ; Bergsma, J. ; Dalen, Pim van; Gool, A.C.M. van; Pool, Jesse van der; Weide, B.E. van der - \ 2018
Wageningen Marine Research - 44 p.
Return of the native facilitated by the invasive? Population composition, substrate preferences and epibenthic species richness of a recently discovered shellfish reef with native European flat oysters (Ostrea edulis) in the North Sea
Christianen, M.J.A. ; Lengkeek, W. ; Bergsma, J.H. ; Coolen, J.W.P. ; Didderen, K. ; Dorenbosch, M. ; Driessen, F.M.F. ; Kamermans, P. ; Reuchlin-Hugenholtz, E. ; Sas, H. ; Smaal, A. ; Wijngaard, K.A. Van Den; Have, T.M. Van Der - \ 2018
Marine Biology Research 14 (2018)6. - ISSN 1745-1000 - p. 590 - 597.
Ostrea edulis - facilitation - native oyster restoration - invasive alien species - North Sea - biodiversity
After being ecologically extinct for almost a century, the discovery of a shellfish reef with native European flat oysters (Ostrea edulis) in the Dutch coastal area of the North Sea by the authors of this study called for an extensive survey to better understand some of the key requirements for the return of the native oyster in coastal waters. We assessed habitat conditions, its potential for increasing biodiversity, and the role of substrate provision by other bivalves such as the invasive alien Pacific oyster (Crassostrea gigas). Using underwater visual census, O. edulis size-frequency distributions and attachment substrate was investigated, as well as the composition of the epibenthic community and substrata types inside quadrats that were distributed across the reef. This reef was found to be composed of native European flat oysters, invasive alien Pacific oysters and blue mussels (Mytilus edulis), alternated with sandy patches. The O. edulis population (6.8 ± 0.6 oysters m−2) consisted of individuals of different size classes. In quadrats with native and non-native oysters the number of epibenthic species was 60% higher compared to adjacent sand patches within the reef. Notably, our results showed that the native oyster predominantly used shell (fragments) of the invasive Pacific oyster as settlement substrate (81% of individuals). Our results optimistically show that conditions for native oyster restoration can be suitable at a local scale in the coastal North Sea area and suggest that the return of native oysters may be facilitated by novel substrate provided by invasive oysters at sites where their distribution overlap.
Effects of β-Glucans and resistant starch on fermentation of recalcitrant fibers in growing pigs
Vries, S. de; Gerrits, W.J.J. ; Kabel, M.A. ; Zijlstra, Ruurd ; Vasanthan, Thava - \ 2017
animal nutrition - carbohydrate structures - digestibility measurements - fermentable fibers - food chemistry - growing pigs - in vivo digestion - nutritional modelling - rapeseed meal
Effects of the presence of β-glucans and resistant starch in diets on nutrient and fiber degradability of rapeseed meal [RSM] (Brassica napus) and Distillers Dried Grain with Solubles (DDGS) were tested in a 2 × 3 factorial arrangement. Two basal diets, containing either 500 g/kg RSM or DDGS and ~400 g/kg corn starch were formulated to meet or exceed nutrient requirements of growing pigs. Corn starch was partly replaced with the β-glucan-extract (β-GLUC; 60 g/kg w/w) or completely replaced with retrograded tapioca (RG; 400 g/kg w/w), resulting in 6 dietary treatments. A total of 10 crossbred barrows (initial body weight, 28 ± 1.4 kg (SD); Duroc × Large White/Landrace; Hypor, Inc., Regina, SK, Canada) were fed the 6 experimental diets. In total, 46 observations were obtained in 10 pigs over 7 periods in an incomplete 10 × 7 Youden square. Each of 7 sequential 14 days experimental periods consisted of a 9 days adaption to the diets followed by 2 days collection of feces, 2 days collection of ileal digesta for digestibility measurements, and 1 day collection of ileal digesta for the measurement of retention time. Pigs were weighed weekly during the experiment after consuming their morning meal. Feces were collected from 08.00 to 17.00 h using bags attached to rings glued around the anus. Bags were collected within 1 h after defecation and immediately frozen (-20 °C). Ileal digesta for digestibility measurements were collected from 08.00 to 17.00 h into plastic bags (10 cm in length and 4 cm in diameter). The bags were removed when filled approximately 70 % with digesta, or after a maximum of 1 h, and immediately frozen (-20 °C). For retention time measurements, on day 14 of each experimental collection, 3.4 g Cr as Cr2O3 (solid phase marker) and 3.4 g Co as Co (II)-EDTA (soluble phase marker) were mixed into the morning meal. Digesta were collected at 45, 90, 180, 270, 360, 540, and 720 min after feed consumption.
Relationship between intramammary infection prevalence and somatic cell score in commercial dairy herds
Shook, G.E. ; Kirk, R.L.B. ; Welcome, Frank L. ; Schukken, Y.H. ; Ruegg, P.L. - \ 2017
Journal of Dairy Science 100 (2017)12. - ISSN 0022-0302 - p. 9691 - 9701.
Intramammary infection - Mastitis pathogens - Somatic cell score - Udder health

We examined consistency of the relationship between intramammary infection (IMI) and somatic cell score (SCS) across several classes of cow, herd, and sampling time variables. Microbial cultures of composite milk samples were performed by New York Quality Milk Production Services from 1992 to 2004. SCS was from the most recent Dairy Herd Improvement test before IMI sampling. Records were analyzed from 79,308 cows in 1,124 commercial dairy herds representing a broad range of production systems. Three binary dependent variables were presence or absence of contagious IMI, environmental IMI, and all IMI. Independent variables in the initial models were SCS, SCS2, lactation number, days in milk, sample day milk yield, use of coliform mastitis vaccine, participant type (required by regulation or voluntary), production system (type of housing, milking system, and herd size), season of sampling, year of sampling, and herd; also the initial models included interactions of SCS and SCS2 with other independent variables, except herd and milk yield. Interaction terms characterize differences in the IMI-SCS relationship across classes of the independent variables. Models were derived using the Glimmix macro in SAS (SAS Institute Inc., Cary, NC) with a logistic link function and employing backward elimination. The final model for each dependent variable included all significant independent variables and interactions. Simplified models omitted SCS2 and all interactions with SCS. Interactions of SCS with days in milk, use of coliform mastitis vaccine, participant type, season, and year were not significant in any of the models. Interaction of SCS with production system was significant for the all IMI model, whereas interaction of SCS with lactation number was significant for the environmental and all IMI models. Each 1 point increase in SCS (or doubling of somatic cell count) was associated with a 2.3, 5.5%, and 9.1% increase in prevalence of contagious, environmental, and all IMI, respectively. Empirical receiver operator characteristic curves and areas under the curve were derived for final and simplified models. The areas under the curve for simplified and final models within each type of IMI differed by 0.009 or less. We concluded that the relationship of IMI with SCS was generally stable over time and consistent across seasons, production systems, and cow factors.

How virtual shade sheds light on plant plasticity
Bongers, Franca J. - \ 2017
Wageningen University. Promotor(en): N.P.R. Anten, co-promotor(en): R. Pierik; J.B. Evers. - Wageningen : Wageningen University - ISBN 9789463432047 - 140
planten - fenotypen - fenotypische variatie - modellen - arabidopsis - natuurlijke selectie - schaduw - reacties - concurrentie tussen planten - licht - plants - phenotypes - phenotypic variation - models - arabidopsis - natural selection - shade - responses - plant competition - light

Phenotypic plasticity is the ability of a genotype to express multiple phenotypes in accordance with different environments. Although variation in plasticity has been observed, there is limited knowledge on how this variation results from natural selection. This thesis analyses how variation in the level of plasticity influences light competition between plants and how this variation could result from selection, driven by light competition, in various environments. As an exemplary case of phenotypic plasticity, this thesis focusses on phenotypic responses of the annual rosette plant Arabidopsis thaliana (Brassicaceae) in response to the proximity of neighbour plants, as signalled through the red : far—red (R:FR) ratio, which are responses associated with the shade avoidance syndrome (SAS).

Plant experiments were conducted to measure variation in these plastic responses and a functional-structural plant (FSP) model was created that simulates plant structures in 3D and includes these organ-level plastic responses while simulating explicitly a heterogeneous light environment. Simulating individual plants that explicitly compete for light, while their phenotype changes through plasticity, gave insights in the role of the level of phenotypic plasticity and site of signal perception on plant competitiveness. In addition, an analysis on how natural selection in different environments acts on the level of plasticity was performed by combining FSP simulations and evolutionary game theoretical (EGT) principles.

The in vitro anthelmintic properties of browse plant species against Haemonchus contortus is determined by the polyphenol content and composition
Mengistu, G. ; Hoste, H. ; Karonen, M. ; Salminen, J.P. ; Hendriks, W.H. ; Pellikaan, W.F. - \ 2017
Veterinary Parasitology 237 (2017). - ISSN 0304-4017 - p. 110 - 116.
Exsheathment - Haemonchus contortus - Larvae - Proanthocyanidins

The aims of the present study were to (a) evaluate the anthelmintic activity of 10 East African browse plant extracts, (b) examine their role in inhibition of Haemonchus contortus larval exsheathment, (c) establish relationship between inhibition of larval exsheathment and browse plant extract polyphenol composition. Acetone/water (70/30%) extracts of air dried leaves of Acacia etbaica, Cadaba farinosa, Capparis tomentosa, Dichrostachys cinerea, Dodonaea angustifolia, Euclea racemosa, Maerua angolensis, Maytenus senegalensis, Rhus natalensis and Senna singueana were used. The larval exsheathment inhibition assay (LEIA) was applied using H. contortus third stage larvae (L3) and browse plant extract concentrations of 0, 150, 300, 600, 1200μg/ml in phosphate buffered saline (PBS). Data were analysed using the PROC MIXED procedure of SAS. Polyvinylpolypyrrolidone (PVPP) was used to evaluate whether polyphenols were involved in L3 exsheathment inhibition. All browse plant extracts significantly (P ≤0.001) inhibited larval exsheathment in a dose dependent manner. The dose required to inhibit 50% of the larvae (EC50) was highest in C. farinosa and lowest in E. racemosa and M. senegalensis. Significant differences (P<0.001) between the control and PVPP treated A. etbaica, C. tomentosa, M. angolensis, R. natalensis and D. cinerea indicates that larval inhibition was largely due to non-phenol compounds. For E. racemosa, M. senegalensis, D. angustifolia and S. singueana, PVPP treatment reversed inhibition activity and in these extracts, inhibition was mostly attributable to tannin and other polyphenols (kaempferol, quercetin and myricetin based glycosides). Overall, the browse plant extracts have anthelmintic property against H. contortus and larval inhibition resulting from the presence of phenolic and non-phenolic compounds.

The effect of quantitative feed restriction on allometric growth in broilers
Klein, S.A.S. van der; Silva, F.A. ; Kwakkel, R.P. ; Zuidhof, M.J. - \ 2017
Poultry Science 96 (2017)1. - ISSN 0032-5791 - p. 118 - 126.
Feed restriction in broilers is aimed at preventing metabolic disorders, increasing feed efficiency, or manipulating carcass conformation. The purpose of the current study was to investigate the effects of modest graded levels feed restriction during the second and third wk of life. Mixed-sex chickens were raised in pens with 4 replications per treatment to 35 d of age. Chickens were fed ad libitum throughout the trial, or 90, 80, or 70% of expected ad libitum feed intake during the second wk of life, or 95, 90, 85, or 80% of expected ad libitum feed intake during the third wk of life. Feed intake, BW, ADG, and feed conversion ratio (FCR) were measured and weekly dissections were conducted to characterize allometric growth of the breast muscle, legs, abdominal fat pad, liver, gastro-intestinal tract (GIT), and heart. Feeding 70% of ad libitum during wk 2 and 80% during wk 3 reduced ADG during the restriction period and reduced BW at the end of the restriction period, but chickens exhibited complete compensatory growth within one wk after the restriction period. No significant effects of restriction treatment were found on BW, FCR, fat pad, empty GIT, breast muscle, heart, legs, and liver weight at d 35, but allometric growth curve for breast muscle was lower in birds fed 80 and 85% of ad libitum during wk 3, and for birds fed 70% of ad libitum in wk 2. Allometric growth curves for all body parts were different between males and females, except for the liver. Females had higher relative fat pad, breast muscle, and liver weight and a lower GIT and heart and leg weight compared with males at d 35. Feed restriction could differentially affect males and females. This study showed that feeding 70% of ad libitum in wk 2 might be beneficial to reduce fat pad, but later feed restriction in wk 3 may reduce breast muscle weight at broiler processing age.
Shellfish reef restoration pilots: Voordelta The Netherlands
Sas, H. ; Kamermans, P. ; Have, T.M. van der; Lengkeek, W. ; Smaal, A.C. - \ 2016
Wageningen Marine Research (Annual report 2016) - 45 p.
Once, shellfish reefs - mainly flat oysters - covered about 20% of the North Sea floor, but diseases, pollution and overfishing have led to a significant decline. As part of the Haringvliet Dream Fund Project (, ARK
Nature and World Wildlife Fund Netherlands are working on shellfish reef restoration. Shellfish, such as mussels and flat oysters, are keystone species for marine biodiversity, since they filter the water, provide shelter and nursery grounds for many marine animals, serve as attachment substrate for plants and range of animals, including birds. They also play an important role in natural coastal protection. Therefore, mussel and flat oyster reef restoration is attempted within the Haringvliet coastal zone (the so-called Voordelta).
This project is co-funded by the ministry for Economic Affairs, the ministry for and Environment, province of South Holland, Port of Rotterdam, National Postcode Lottery and LIFE. ARK Nature leads this project. The North Sea Flat (a cooperation of Wageningen Marine Research, Bureau Waardenburg and Sas Consultancy) is responsible for the execution of the current two pilots: maintenance, monitoring, analysis of monitoring results and reporting.
The effect of dry period length and antibiotic treatment at drying off on somatic cell counts across the dry period
Hoeij, R.J. van; Knegsel, A.T.M. van; Kemp, B. ; Lam, T.G.J.M. - \ 2016
Management measures to reduce the risk of new intramammary infections (IMI) during the precalving period include use of dry cow antibiotics. Blanket dry cow therapy is not allowed in several European countries, among which the Netherlands. Moreover, shorter dry periods are of interest because of beneficial effects on the energy balance and metabolic status in the subsequent lactation. The aim was to study the effect of dry period (DP) length on SCC in the subsequent lactation and occurrence of IMI, based on SCC, across the dry period. This aim was approached in 2 separate experiments: experiment 1 was conducted with use of dry cow antibiotics and experiment 2 without use of dry cow antibiotics. In experiment 1 Holstein-Friesian cows (n=167) were randomly assigned to three DP lengths (0, 30, 60 days). Cows with a 30-d or 60-d DP were treated with dry cow antibiotics (Supermastidol®, Virbac Animal Health, Barneveld, the Netherlands) at drying off. In experiment 2, Holstein-Friesian cows (n=127) were randomly assigned to two DP lengths (0 or 30 days) and were not treated with dry cow antibiotics. Data were analysed using a logistic regression model (SAS Institute Inc., 2011), including DP length as fixed effect. Somatic cell count was log transformed before statistical analysis (LnSCC). Data are expressed as LMEANS ± SE. In experiment 1, cows with a 0-d DP had a greater average SCC in the subsequent lactation (LnSCC 5.01 ± 0.06) than cows with a 30-d (LnSCC 4.68 ± 0.06) or 60-d DP (LnSCC 4.52 ± 0.06) (P<0.01). The proportion of cows with a chronic IMI (SCC ≥ 200,000 both pre- and postpartum) was greater in cows with a 0-d DP (5/10), than in cows with a 30-d DP (1/13) or a 60-d DP (1/12) (P=0.04). In experiment 2, cows with a 0-d DP had a greater postpartum average SCC (LnSCC 4.51 ± 0.04), than cows with a 30-d DP (LnSCC 4.24 ± 0.04) (P<0.01). The proportion of cows with a chronic IMI during the precalving period was not different between cows with a 0-d DP (6/11) or a 30-d DP (2/6) (P=0.47). Postpartum average SCC for lactation is greater in cows with a 0-d DP, than in cows with a 30-d DP, regardless of use of dry cow antibiotics. Studies are ongoing to evaluate whether the greater SCC in early lactation in cows with a 0-d DP is actually correlated with intramammary bacterial infections.
In vitro inhibitory activities of two browse extracts on larval exsheathment of goat nematodes
Mengistu, G.F. ; Hoste, H. ; Hendriks, W.H. ; Pellikaan, W.F. - \ 2016
In: 16th International Conference on Production Diseases in Farm Animals. - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086862856 - p. 71 - 71.
Nematodes impose a significant economic loss in goat production systems in Ethiopia. Haemonchus contortus and Trichostrongylus colubriformis are the most prevalent species of nematodes. Control using synthetic anthelimintic drugs is limited due to inaccessibility or high cost and tannin-containing forages could provide a cheap and sustainable alternative. The present study examined anthelmintic properties of two tannin-containing browse against H. contortus and T. colubriformis infective larval stage (L3), and to compare larval susceptibility to extracts. The larval exsheathment inhibition assay was employed where the L3 were exposed to extracts obtained from acetone/water (70:30, v/v) extracted dried leaves of Capparis tomentosa and Dodonea angustifolia. Condensed tannin concentrations were 6.8 and 9.3 Abs550 nm/g DM, respectively as measured by the modified Butanol-HCl-Iron method. The L3 (ca. 1000 L3/ml) were obtained from monospecifically infected donor goats. Treatments included extract doses of 1,200, 600, 300, 150 and 0 (control) μg/ml PBS. The L3 were exposed for 3 h, centrifuged and washed 3 times with PBS. Four replicates from each dose were prepared and artificial exsheathment induced using a 40 μl solution of sodium hypochlorite (2%, w/v) and sodium chloride (16.5%, w/v) diluted in 1:400 or 1:500 PBS. Larval exsheathment was recorded microscopically (200×) at 0, 20, 40, and 60 min. Percentage exsheathment was calculated as the ratio of exsheathed over the total exsheated and ensheated larvae. Percentage exsheathment data were subjected to GLM of SAS. The effective dose that causes 50% L3 exsheathment inhibition (EC50) was calculated using a PoloPlus software. There was a dose dependent effect on exsheathment (P<0.001) across extracts with complete inhibition for 1,200 μg/ml regardless of larval species. Mean EC50 values were 332.9 and 275.8 (H. contortus), and 359.6 and 386.9 μg/ ml (T. colubriformis) with C. tomentosa and D. angustifolia, respectively. The extracts exhibited anthelmintic properties against both nematode species and the mean EC50 values suggested higher susceptibility of H. contortus. Results suggest the possible use of the two browse species for simultaneous control of H. contortus and T. colubriformis.
Effects of feed access after hatch and inclusion of fish oil and medium chain fatty acids in a pre-starter diet on broiler chicken growth performance and humoral immunity
Lamot, D.M. ; Klein, S.A.S. van der; Linde, I.B. van de; Wijtten, P.J.A. ; Kemp, B. ; Brand, H. van den; Lammers, A. - \ 2016
Animal 10 (2016)9. - ISSN 1751-7311 - p. 1409 - 1416.
first week nutrition - fish oil - humoral immunity - medium chain fatty acids

Delayed feed and water access is known to impair growth performance of day old broiler chickens. Although effects of feed access on growth performance and immune function of broilers have been examined before, effects of dietary composition and its potential interaction with feed access are hardly investigated. This experiment aimed to determine whether moment of first feed and water access after hatch and pre-starter composition (0 to 7 days) affect growth rate and humoral immune function in broiler chickens. Direct fed chickens received feed and water directly after placement in the grow-out facility, whilst delayed fed chickens only after 48 h. Direct and delayed fed chickens received a control pre-starter diet, or a diet containing medium chain fatty acids (MCFA) or fish oil. At 21 days, chickens were immunized by injection of sheep red blood cells. The mortality rate depended on an interaction between feed access and pre-starter composition (P=0.014). Chickens with direct feed access fed the control pre-starter diet had a higher risk for mortality than chickens with delayed feed access fed the control pre-starter diet (16.4% v. 4.2%) whereas the other treatment groups were in-between. BW gain and feed intake till 25 days in direct fed chickens were higher compared with delayed fed chickens, whilst gain to feed ratio was lower. Within the direct fed chickens, the control pre-starter diet resulted in the highest BW at 28 days and the MCFA pre-starter diet the lowest (Δ=2.4%), whereas this was opposite for delayed fed chickens (Δ=3.0%; P=0.033). Provision of MCFA resulted in a 4.6% higher BW gain and a higher gain to feed ratio compared with other pre-starter diets, but only during the period it was provided (2 to 7 days). Minor treatment effects were found for humoral immune response by measuring immunoglobulins, agglutination titers, interferon gamma (IFN- γ ), and complement activity. Concluding, current inclusion levels of fish oil (5 g/kg) and MCFA (30 g/kg) in the pre-starter diet appear to have limited (carryover) effects on growth and development, as well as on humoral immune function.

Storage selection functions : A coherent framework for quantifying how catchments store and release water and solutes
Rinaldo, Andrea ; Benettin, Paolo ; Harman, C.J. ; Hrachowitz, Markus ; McGuire, K.J. ; Velde, Ype Van Der; Bertuzzo, Enrico ; Botter, Gianluca - \ 2015
Water Resources Research 51 (2015)6. - ISSN 0043-1397 - p. 4840 - 4847.
basin-scale transport - biogeochemical processes - hydrologic response - mixing and dispersion - residence time distributions - travel time distributions

We discuss a recent theoretical approach combining catchment-scale flow and transport processes into a unified framework. The approach is designed to characterize the hydrochemistry of hydrologic systems and to meet the challenges posed by empirical evidence. StorAge Selection functions (SAS) are defined to represent the way catchment storage supplies the outflows with water of different ages, thus regulating the chemical composition of out-fluxes. Biogeochemical processes are also reflected in the evolving residence time distribution and thus in age-selection. Here we make the case for the routine use of SAS functions and look forward to areas where further research is needed. Key Points: Storage selection functions recapitulate age dynamics Formulation of transport by travel time distributions Flow and transport at catchment scales

Availability of aromatic amino acids in the blood plasma differs between lines of laying hens selected for low mortality or production traits
Birkl, P. ; Franke, L. ; Rodenburg, T.B. ; Wurbel, H. ; Harlander, A. - \ 2015
In: Book of Abstracts 2015 PSA Annual Meeting. - Poultry Science Association - p. 21 - 21.
The mechanisms underlying feather pecking (FP) behavior are still unclear. However, neuronal monoamine (serotonin and dopamine) pathways are thought to play a major role. As monoamine precursors, aromatic amino acids (AAA) compete for active transport at the blood brain barrier the central monoamine synthesis is influenced by AAA concentration in the periphery. This study compared the plasma availability of AAA in 2 lines of layers: One selected for low mortality (LM; n = 132), showing low FP and one control line (C), selected for production traits only (n = 132). We expected that plasma levels of AAA are of high individual variability and instable over time, and that most pronounced differences between lines could be related to tyrosine (TYR) level. Blood samples of 132 birds per line, kept in groups of 11, were collected in wk 24 and 29. An AA-profile was received by HPLC of platelet-poor plasma. Data were analyzed using PROC MIXED (SAS 9.3) by line and week and their interactions as fixed effects, pen (line) as random effect and week/bird (pen) as repeated effect. Per line, birds did not differ in PHEN, TYR, TRP or TRP/AAA levels. However, TYR decreased over time (P <0.003) for both lines. An interaction was found between increased PHEN/TYR ratios and age, attributed to lines. Moreover, the line (P <0.05), week (P <0.002) and line × week (P <0.001) interactions in PHEN/TYR ratios were found to be increasing for C birds over time but not for LM birds (P <0.67). Another interaction, attributed to lines and age, could be found in the case of TYR/ TRP ratios, decreasing significantly over time for LM birds (P <0.0001) but increasing in control birds (P <0.0009). These results indicate that there are substantial age-dependent differences in circulating AAA between these 2 lines, which could be based on differences in the metabolic activity of the liver. We therefore suggest that further insights into the contribution of blood AAA to the central synthesis of neurotransmitters are required to gain a better understanding of the mechanisms underlying FP in layers.
Rumen degradability of wheat straw is related to changes in lignin properties after fungal treatment
Kuijk, S.J.A. van; Sonnenberg, A.S.M. ; Baars, J.J.P. ; Hendriks, W.H. ; Cone, J.W. - \ 2015
In: Book of abstracts of 2015 Joint Annual Meeting of ADSA-ASAS. - - p. 605 - 605.
The aim was to improve the rumen degradability of wheat straw (WS), which has relatively high cell wall content. Plant cell walls consist of hemicellulose and cellulose that are bound to lignin. These carbohydrates can be an important source of energy for rumen microbes. However, rumen microbes cannot degrade lignin, which blocks the availability of the carbohydrates. The availability of carbohydrates can be increased when lignin is removed in a pre-treatment. In nature, dead plants can be degraded by fungi. Some fungal species degrade lignin without consuming cellulose during vegetative growth. One of the selective lignin degrading fungi, Lentinula edodes was used to test the improvement in rumen degradability of WS. Two conditions were tested in triplicate: autoclaved WS inoculated with L. edodes and autoclaved WS as control. After 12 weeks of incubation at 24°C, rumen degradability was determined with the in vitro gas production (IVGP) technique (Cone et al., 1996). Lignin, hemicellulose and cellulose content were determined according to the methods described by Van Soest et al. (1991). Changes in chemical composition and IVGP upon fungal treatment were compared with the control, using the generalized linear model method in SAS (v9.3). To test the effect of changes in lignin structure and properties, pyrolysis gas chromatography-mass spectrometry (py-GC/MS) was done on fungal treated WS and the control. L. edodes treatment for 12 weeks increased (P <0.05) IVGP of WS compared with untreated WS. Cellulose content was unchanged, while hemicellulose and lignin content decreased (P <0.05). In addition to a decrease in total lignin, py-GC/MS showed an increasing amount of lignin degradation products. Upon L. edodes treatment not only a total degradation of lignin occurred, but the composition of lignin also changed. Lignin in WS consists of syringyl (S) and guaiacyl (G) units in a 1:1 ratio. L. edodes degraded more S than G units, since the S/G ratio decreased. This decrease in S/G ratio was correlated to an increase in IVGP. We conclude that the L. edodes treatment increased the IVGP of WS, which was correlated to both lignin content and composition.
The effect of lactic acid bacteria as probiotics or silage inoculants on in vitro rumen digestibility, total gas and methane production
Ellis, J.L. ; Bannink, A. ; Hindrichsen, I.K. ; Kinley, R.D. ; Pellikaan, W.F. ; Milora, N.L. ; Dijkstra, J. - \ 2015
In: Book of abstracts of 2015 Joint Annual Meeting of ADSA-ASAS. - - p. 246 - 247.
Lactic acid bacteria (LAB) included as a probiotic or silage inoculant may affect rumen fermentation, OM digestibility and methane (CH4) emissions in cattle. Therefore, 2 in vitro gas production trials were conducted to pre-screen several potential LAB inoculants at several inoculation levels, using different LAB mixtures, and on different silage substrates. In Experiment 1 the dose-response effects of 3 LAB inoculants added as probiotics (0.0, 5 × 105, 1 × 106 and 5 × 106 cfu/ mL) on in vitro total gas and CH4 production were examined using grass silage as the substrate. In Experiment 2, 3 LAB inoculant mixtures were examined while varying the substrate. Substrates were inoculated with LAB before ensiling, and were ryegrass/clover (RCS), corn (CS) and ryegrass (RS) silage. Data were analyzed with proc MIXED of SAS with LAB inoculant × dose as a fixed effect, and dose was analyzed via orthogonal polynomial contrasts (Experiment 1), and using substrate, inoculation and substrate × inoculation as fixed effects (Experiment 2). Results showed that not all LAB affected in vitro fermentation. In Experiment 1, L. plantarum (LP) but not L. lactis (LL) or a 1:1 mixture of LL and LP, resulted in significant increases in OM digestibility (P = 0.023), and there was a trend for several dose related responses. In Experiment 2, LAB showed both strain and substrate-specific responses. In RS, an inoculation of a mixture of L. plantarum, L.buchneri and L. lactis (LM1) increased OM digestibility, while inoculations of L. buchneri and L.lactis (LM2) and L. plantarum, L. lactis and E. faecium (LM3) decreased OM digestibility in RCS (inoculation P <0.001). These effects were generally mirrored by changes in gas and CH4 production. In CS, no effects were observed on OM digestibility, total gas or CH4 production. From these results we conclude that LAB may be most effective in grass based silages (compared with corn) for altering OM digestibility, and that the LP treatment from Experiment 1, or the LM1 treatment from Experiment 2, may be most promising for evaluation in vivo.
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