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 genotype, sow rearing system and outdoor acces on piglet survival in extensive systems
    Vermeer, H.M. ; Binnendijk, G.P. ; Riel, J.W. van; Leenhouwers, J. - \ 2014
    In: Book of abstracts of the 65th Annual Meeting of the European Federation of Animal Science. - Wageningen : Wageningen Academic Publishers - ISBN 9789086862481 - p. 251 - 251.
    Breeding replacement gilts for organic pig herds
    Leenhouwers, J.I. ; Napel, J. ten; Hanenberg, E.H.A.T. ; Merks, J.W.M. - \ 2011
    Animal 5 (2011)4. - ISSN 1751-7311 - p. 615 - 621.
    to-conception interval - lactation length - litter size - systems - performance - mortality - livestock - traits - growth
    In this study, breeding structures and commercial sow lines were evaluated by economic and genetic simulation studies for their suitability to provide the Dutch organic pig sector with replacement gilts. Sow and litter performance from over 2000 crossbred sows from 2006 to 2007 were collected on 11 to 14 Dutch organic pig herds, respectively, and compared with conventional herds. Results showed that organic herds had lower farrowing rates (3.6% to 7.5%), more live born piglets per litter (0.4% to 1.2%) and higher preweaning mortality rates (7% to 13%) compared to conventional herds. These results were used to simulate economic performance of various combinations of breeding structures and sow lines under organic conditions, under the assumption of absence of genotype-environment interactions. Sow and litter performance data under organic conditions (total piglets born/litter, stillborn piglets/litter, mortality until weaning, lactation length, interval weaning-oestrus and sow culling rate) and the costprice calculation for the Dutch organic pig sector were used as input for the economic simulation studies. The expected genetic progress was simulated for three potential breeding structures of the organic sector: organic breeding herds producing F1 gilts (OrgBS), a flower breeding system (FlowerBS) and a two-line rotation breeding system (RotBS). In FlowerBS, an organic purebred sow line is bred, using on-farm gilt replacement. The OrgBS with a Yorkshire X Landrace cross had the highest margin per sow place ((sic)779), followed by RotBS with Yorkshire X Landrace cross ((sic)706) and FlowerBS with Yorkshire sow line ((sic)677). In case that an organic purebred sow population of 5000 sows would be available, FlowerBS gave the highest genetic progress in terms of cost price reduction ((sic)3.72/slaughter pig per generation), followed by RotBS and OrgBS ((sic)3.60/slaughter pig per generation). For FlowerBS, additional costs will be involved for maintaining a dedicated breeding programme. In conclusion, OrgBS using conventional genetics is economically the most viable option for the organic pig sector. However, this structure has clear disadvantages in terms of risks with regard to disease transmission and market demand. FlowerBS using a dedicated purebred organic line will only be cost-effective if sow population size is sufficiently large. RotBS might be a viable alternative, especially in combination with artificial insemination (AI) boars that are ranked according to an organic selection index. Regardless of breeding structure, the Yorkshire sow line gave the highest prolificacy and the highest economic returns on organic herds.
    De voorziening van biologische opfokzeugen = The supply of organic gilts
    Napel, J. ten; Leenhouwers, J. ; Merks, J. - \ 2009
    Wageningen : Livestock Research (Rapport / Livestock Research 252) - 19
    biologische landbouw - varkenshouderij - gelten - dierveredeling - biologische productie - certificering - varkensfokkerij - organic farming - pig farming - gilts - animal breeding - biological production - certification - pig breeding
    De biologische varkenshouders in Nederland maken voor de vervanging van hun zeugen gebruik van fokmateriaal uit de gangbare varkenshouderij. Dit via aankoop van fokgelten of via aankoop van sperma van gangbare zeugenlijnen voor de eigen aanfok van fokgelten. Echter, biologische bedrijven die alle fokgelten voor vervanging aankopen van niet-biologische bedrijven voldoen niet aan de SKAL richtlijn. Het doel van deze studie is om rassen, kruisingen en fokkerijstructuren te vergelijken om de meest geschikte werkwijze te vinden waarmee de biologische varkenshouderij zichzelf kan voorzien van fokgelten.
    Fermentability of carbohydrates in an in vitro batch culture method using inocula from Nile tilapia (Oreochromis niloticus) and European sea bass (Dicentrarchus labrax).
    Leenhouwers, J.I. ; Pellikaan, W.F. ; Huizinga, H.F.A. ; Coolen, R.O.M. ; Verreth, J.A.J. ; Schrama, J.W. - \ 2008
    Aquaculture Nutrition 14 (2008)6. - ISSN 1353-5773 - p. 523 - 532.
    volatile fatty-acids - fresh-water fish - gas-production - herbivorous fishes - gut microbes - gastrointestinal-tract - cellulase activity - stomached animals - intestinal-tract - digestive tracts
    This study investigated in vitro fermentability of wheat-derived carbohydrates using inocula of Nile tilapia and European sea bass. Distal intestinal contents were incubated in bottles containing one of four fermentable substrates, i.e. glucose (GL), native wheat starch (WS), arabinoxylan (ABX) and whole wheat (WHT). Cumulative gas production was measured for 168 h. At the end of incubation, fermentation end-products were measured. A monophasic model was fitted to the gas production profiles of each bottle, thereby allowing calculation of gas kinetic parameters. Total gas production (mL g¿1 organic matter) differed significantly between substrates for tilapia (GL: 268.9; WS: 388.0; ABX: 411.9; WHT: 413.2) and sea bass (GL: 338.6; WS: 189.3; ABX: 296.3; WHT: 264.0). Fermentation rates were highest for GL and lowest for WS, both for tilapia and sea bass. Fermentation of ABX and WHT yielded predominantly acetic and butyric acid, whereas GL and WS yielded also significant amounts of lactic acid. Ammonia (mL g¿1 organic matter) was highest for WHT (tilapia: 80.36; sea bass: 70.39) and lowest for GL (tilapia: 46.01; sea bass: 32.83). In conclusion, intestinal microbes from Nile tilapia and European sea bass have the potential to ferment carbohydrates. Large differences exist in fermentability and composition of fermentation end-products between carbohydrates.
    Digesta characteristics in relation to nutrient digestibility and mineral absorption in Nile tilapia (Oreochromis niloticus L.) fed cereal grains of increasing viscosity
    Leenhouwers, J.I. ; Ortega, R.C. ; Verreth, J.A.J. ; Schrama, J.W. - \ 2007
    Aquaculture 273 (2007)4. - ISSN 0044-8486 - p. 556 - 565.
    chain fatty-acids - nonstarch polysaccharide - gastrointestinal-tract - antinutritive activity - diets - fermentation - starch - feed - ingredients - performance
    Soluble non-starch polysaccharides (NSP) present in cereal grains may affect performance of Nile tilapia through changes in digesta characteristics. The objective of this study was to investigate whether dietary cereal grains of increasing viscosity induce changes in digesta viscosity, dry matter and volatile fatty acids (VFA) and if these changes explain differences in nutrient digestibility and mineral absorption. Four experimental diets were formulated by adding 40% grains to a basal diet to obtain a range of dietary viscosities, increasing in the order of maize, barley, wheat and rye. The diets were assigned to 16 tanks with 40 fish (mean weight 70 g) each. Digesta viscosity increased with increasing grain viscosity (P <0.001), whereas digesta dry matter decreased with increasing grain viscosity (P <0.05). No significant differences were found among diets in total concentration and type of VFA. Nutrient digestibility was not significantly correlated with digesta viscosity. Of all nutrients, only starch digestibility was significantly negatively correlated with digesta dry matter in the middle intestine (r = ¿ 0.57; P = 0.03). Absorption of sodium was significantly negatively correlated with digesta viscosity in all intestinal segments (r = ¿ 0.76 to ¿ 0.82; P <0.001) and positively correlated with digesta dry matter in all intestinal segments (r = + 0.60 to + 0.67; P <0.05), except for the proximal intestine (P = 0.18). Of the other minerals, potassium and magnesium absorption were positively correlated with digesta dry matter in the distal (r = + 0.56; P = 0.03) and proximal (r = + 0.54; P = 0.04) intestine, respectively. Phosphorus absorption was significantly negatively correlated with dry matter in the stomach (r = ¿ 0.55; P = 0.03), middle (r = ¿ 0.58; P = 0.02) and distal (r = ¿ 0.54; P = 0.04) intestine. In conclusion, viscous cereal grains induce increases in digesta viscosity and decreases in digesta dry matter in Nile tilapia. These changes do not explain differences in nutrient digestibility among diets, but seem more related to differences in mineral absorption. The strong negative correlations between digesta viscosity and sodium absorption suggest negative effects of dietary viscous grains on intestinal water balance.
    Digesta characteristiscs and performance of African catfish (Clarias gariepinus) fed cereal grains that differ in viscosity
    Leenhouwers, J.I. ; Veld, M. ter; Verreth, J.A.J. ; Schrama, J.W. - \ 2007
    Aquaculture 264 (2007). - ISSN 0044-8486 - p. 330 - 341.
    tilapia oreochromis-niloticus - marine herbivorous fishes - nonstarch polysaccharide - atlantic salmon - nutrient digestibility - antinutritive activity - broiler-chickens - feed ingredients - wheat pentosans - rainbow-trout
    Inclusion of cereal grains in fish diets may induce changes in digesta characteristics with possible consequences for fish performance. Especially viscosity characteristics of the dietary ingredients may induce these changes. The aim of this study was to investigate effects of dietary cereal grains (maize, wheat, barley, rye) differing in viscosity on digesta characteristics (viscosity, dry matter and volatile fatty acids), nutrient digestibility and performance (feed intake and growth) in African catfish. We hypothesized that increased dietary viscosity will induce changes in digesta characteristics that are associated with reduced nutrient digestibility and growth performance. Five experimental diets were formulated by adding grains to a basal diet to obtain a range of dietary viscosities, increasing in the order of: 1) 400 g kg¿ 1 maize (M-40); 2) 400 g kg¿ 1 wheat (W-40); 3) 400 g kg¿ 1 barley (B-40); 4) 200 g kg¿ 1 maize and 200 g kg¿ 1 rye (M-20/R-20); 5) 400 g kg¿ 1 rye (R-40). The diets were assigned to 12 tanks with 50 fish each. Feed intake during satiation feeding did not differ between dietary groups (P = 0.46). Growth performance differed between dietary treatments (P = 0.04), but showed no decreasing trend with increasing dietary viscosity. Digesta viscosity in the proximal intestine differed between dietary treatments (P <0.001) and increased with increasing dietary viscosity. Dry matter content of the distal digesta differed significantly between groups (P <0.001) and was lowest for fish fed the most viscous diets (M-20/R-20 and R-40). Total volatile fatty acid concentrations in the distal intestine did not significantly differ between dietary groups (P = 0.48), but were numerically highest for fish fed the R-40 diet. Digestibility of protein and fat differed significantly between dietary groups (protein: P = 0.05; fat: P = 0.003). Fish fed the R-40 diet had the lowest digestibility for protein and fat and also the lowest plasma cholesterol concentrations. Digestibility of total non-starch polysaccharides (NSP) varied considerably between dietary groups (P = 0.03). Fish fed the W-40 diet had the lowest NSP digestibility (4.0%), which suggests that the NSP fraction of wheat was hardly utilized by the intestinal microbiota. Moderately positive NSP digestibilities for the M-40 (48.4%) and M-20/R-20 (55.5%) groups indicated that African catfish could utilize NSP derived from maize reasonably well. In conclusion, dietary inclusion of viscous grains increases digesta viscosity in African catfish. Intestinal fermentation activity, digesta dry matter content and nutrient digestibility seem to be affected beyond a certain threshold for viscosity. Changes in digesta characteristics are not accompanied by reduced fish performance.
    Relationship between bacterial composition of digesta and surrounding water in Nile tilapia (Oreochromis niloticus) and European sea bass (Dichentrarchus labrax) kept in recirculation systems
    Leenhouwers, J.I. ; Chabrillon, M. ; Huizing, H.F.A. ; Smidt, H. ; Verreth, J.A.J. ; Schrama, J.W. - \ 2006
    In: 12th International Symposium on Fish Nutrition and Feeding: Program and Abstracts, May 28-June 1 2006, Biarritz, France. - Biarritz, France : - p. 291 - 291.
    Digesta viscosity, nutrient digestibility and organ weights in African catfish (Clarias gariepinus) fed diets supplemented with different levels of a soluble non-starch polysaccharide
    Leenhouwers, J.I. ; Adjei-Boateng, D. ; Verreth, J.A.J. ; Schrama, J.W. - \ 2006
    Aquaculture Nutrition 12 (2006)2. - ISSN 1353-5773 - p. 111 - 116.
    sesbania-aculeata seeds - broiler-chickens - intestinal development - oreochromis-niloticus - growth - tilapia - fish - carboxymethylcellulose
    The objective of the present study was to investigate if dietary soluble non-starch polysaccharides (NSP) increase digesta viscosity, reduce nutrient digestibility and increase organ weights in African catfish. The fish (mean weight 80 g) were fed diets supplemented with the soluble NSP guar gum at three levels, 0 g kg1 (GG0), 40 g kg1 (GG4) and 80 g kg1 (GG8). Guar gum inclusion significantly increased digesta viscosity in the proximal (GG0: 1.7 centipoise or cP; GG4: 84.9 cP; GG8: 98.3 cP) and distal (GG0: 1.9 cP; GG4: 109.8 cP; GG8: 66.4 cP) intestine. Apparent digestibility coefficients (ADC) were significantly lower for the GG8 diet than the GG0 diet (dry matter: 52% versus 69%; protein: 77% versus 90%; ash: 41% versus 54%; energy: 60% versus 77%). The ADC of dry matter and energy were significantly lower for the GG4 diet than the GG0 diet. The relative growth rate of metabolic weight (14.5¿15.4 g kg0.8 day1) and feed conversion ratio (0.8) did not differ between diets. Fish fed the GG8 diet had a significantly higher somatic stomach index than GG0 fish (0.71% versus 0.65% body weight). The intestinal somatic index tended to increase with increasing guar gum supplementation (GG0: 1.08%; GG4: 1.23%; GG8: 1.59%). In conclusion, high digesta viscosities in the guar gum fed fish may explain the observed reduced nutrient digestibilities and increases in digestive organ weights
    Fermentability of non-starch polysaccharides in an in vitro batch culture method in Nile tilapia fed different sources of wheat and soya fibre
    Leenhouwers, J.I. ; Ubah, E.J. ; Pellikaan, W.F. ; Coolen, R.O.M. ; Verreth, J.A.J. ; Schrama, J.W. - \ 2006
    In: 12th International Symposium on Fish Nutrition and Feeding: Program and Abstracts, May 28-June 1 2006 Biarritz, France : - p. 293 - 293.
    Plant ingredients in fish diets: effects of non-starch polysaccharides
    Schrama, J.W. ; Leenhouwers, J.I. ; Verreth, J.A.J. - \ 2005
    Digesta viscosity, nutrient digestibility and fermentation activity in Nile tilapia fed cereal based diets that differ in soluble non-starch polysaccharide content
    Leenhouwers, J.I. ; Ortega, C. ; Verreth, J.A.J. ; Schrama, J.W. - \ 2005
    In: Extended Abstracts and Short Communications.European Aquaculture Society.Special Publication, Trontheim, 2005. - - p. 299 - 299.
    Type of dietary fibre (soluble versus insoluble) influences digestion, faeces characteristics and faecal waste production in Nile tilapia (Oreochromis niloticus L.)
    Amirkolaie, A.K. ; Leenhouwers, J.I. ; Verreth, J.A.J. ; Schrama, J.W. - \ 2005
    Aquaculture Research 36 (2005)12. - ISSN 1355-557X - p. 1157 - 1166.
    broiler-chickens - nutrient digestibility - gastrointestinal-tract - rainbow-trout - feed-intake - guar gum - growth - carboxymethylcellulose - viscosity - cellulose
    The physico-chemical properties of nutrients influence the physical characteristics of faeces and thus may affect waste removal efficiency. The aim of this study is to assess the effect of type of non-starch polysaccharide (NSP) on digesta viscosity, faeces recovery and nutrient digestibility in Nile tilapia. Insoluble (cellulose) and soluble (guar gum) NSPs were included separately and combined at a level of 8%, thereby formulating four experimental diets. The diets were assigned to 16 tanks with 35 fish each, with four replicates for each diet. Cellulose inclusion did not influence digesta viscosity, growth and digestibility of protein and starch and tended to increase faeces recovery (P=0.06). Guar gum inclusion increased digesta viscosity and reduced the growth and digestibility of protein, fat and starch (P
    Kunnen vissen vegetariër worden
    Leenhouwers, J.I. ; Schrama, J.W. ; Verreth, J.A.J. - \ 2004
    Utrecht : Technologiestichting STW
    Effects of different dietary levels of guar gum on digesta viscosity and performance of African catfish
    Leenhouwers, J.I. ; Schrama, J.W. ; Adjei-Boateng, D. ; Verreth, J.A.J. - \ 2004
    In: 11th International Symposium on Nutrition and Feeding in Fish (ISNFF)2004,Phuket,Thailand - p. 208 - 208.
    Effect of type of dietary fibre on faeces characteristics, digestibility and performance in tilapia
    Amirkolaie, A.K. ; Schrama, J.W. ; Leenhouwers, J.I. ; Verreth, J.A.J. - \ 2004
    In: 11th International Symposium on Nutrition and Feeding in Fish (ISNFF)2004,Phuket,Thailand - p. 218 (P105) - 218 (P105).
    Digesta viscosity and nutrient digestibility in European sea bass in a fresh water and marine environment
    Leenhouwers, J.I. ; Santos, G.A. ; Schrama, J.W. ; Verreth, J.A.J. - \ 2004
    In: Conference on 'Biotechnologies for quality', Barcelona, Spain, 20-23 October 2004 - p. 475 - 476.
    Digesta viscosity, growth performance and nutrient digestibility in African catfish fed grain sources with different viscosities
    Leenhouwers, J.I. ; Schrama, J.W. ; Veld, M. ter; Verreth, J.A.J. - \ 2004
    In: 11th International Symposium on Nutrition and Feeding in Fish (ISNFF)2004,Phuket,Thailand - p. 73 - 73.
    Marker polymorphisms in the porcine genes for muscle glycogen synthase (GYS1) and muscle glycogen phosphorylase (PYGM)
    Pas, M.F.W. te; Leenhouwers, J.I. ; Knol, E.F. ; Booij, M.H. ; Priem, J. ; Lende, T. van der - \ 2003
    Animal Genetics 34 (2003)2. - ISSN 0268-9146 - p. 157 - 158.
    skeletal-muscle - mutation - pig
    Stillbirth in the pig in relation to genetic merit for farrowing survival
    Leenhouwers, J.I. ; Wissink, P. ; Lende, T. van der; Paridaans, H. ; Knol, E.F. - \ 2003
    Journal of Animal Science 81 (2003). - ISSN 0021-8812 - p. 2419 - 2424.
    preweaning mortality - swine - traits - parturition - parameters - selection - growth - birth
    The objectives of this study were to analyze the incidence of different categories of stillborn piglets in relation to genetic merit for farrowing survival of sows and litters and to analyze relationships of total number of piglets born per litter, average BW of the litter, and within-litter variation in BW with genetic merit for farrowing survival of sows and litters. Records of 336 purebred litters, produced by 307 first-to eighth-parity sows, were collected on a nucleus farm in Brouennes, France. Breeding values for farrowing survival were estimated for sows (EBVfs(-)maternal) and litters (EBVfs(-)direct) using a large data set from which information obtained in the current study was excluded. For each litter, BW, number of stillborn piglets (classified as nonfresh stillborn, prepartum stillborn, intrapartum stillborn, and postpartum stillborn), and number of live-born piglets were recorded. Birth weights of stillborn piglets were lower than BW of live-born piglets (P <0.0001), except for prepartum stillbirths. The total number of stillborn piglets per litter and the number of stillborn piglets in each category decreased with increasing EBVfs(-)maternal (P <0.01). An increase in EBVfs(-)direct was also associated with a decrease in the total number of stillborn piglets per litter (P <0.01). This decrease was due to a decrease in the number of nonfresh, prepartum, and postpartum stillborn piglets but not to a decrease in the number of intrapartum stillborn piglets. Probabilities of stillbirth in relation to EBVf(-)maternal were higher than probabilities of stillbirth in relation to EBVf direct. Total number of piglets born decreased with increasing EBVfs(-)direct (P = 0.0003), but was not related to EBVfs(-)maternal. Average BW of the litter (P <0.0001) and within-litter variation in BW (P = 0.05) decreased with increasing EBVfs(-)maternal but were not related to EBVfs(-)direct. Selection for the maternal genetic component of farrowing survival seems a better strategy than selection for the direct genetic component. Selection for the maternal genetic component of farrowing survival reduces stillbirth in all categories and does not affect litter size.
    Effects of sow nutrition during gestation on perinatal piglet viability : a review
    Leenhouwers, J.I. ; Jansman, A.J.M. ; Beynen, A.C. ; Lende, T. van der - \ 2002
    Lelystad : ID-Lelystad (Rapport ID-Lelystad 2242) - 62 p.
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