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.

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Financial value-chain analysis : tuna, shrimp, soy and beef
Duijn, A.P. van; Beukers, R. ; Cow an, Roberta B. ; Judge, L.O. ; Pijl, W. van der; Römgens, Indra ; Scheele, Fleur ; Steinweg, Tim - \ 2016
LEI Wageningen UR (Brochure / LEI Wageningen UR 2016-029) - 50 p.
supply chain management - agro-industrial chains - commodities - retail marketing - finance - tuna - shrimps - glycine (fabaceae) - beef - world - ketenmanagement - agro-industriële ketens - basisproducten - marketing voor de detailhandel - financiën - tonijn - garnalen - rundvlees - wereld
This brochure offers a detailed analysis of the financial vehicles and mechanisms that drive the expansion of production of the following four commodities: skipjack canned tuna; cultured shrimp; soy; and beef. The commodities were selected in view of their global economic importance and their potentially adverse impact on the environment. The financial sector (investors, lenders, insurers, funds, etc.) serves as a gate-keeper to capital flows that are critical in supporting companies’ expansions of operational capacity. This sector can significantly influence how these businesses exploit renewable resources. In this brochure therefore:  The supply chains for each commodity were verified by geography;  The top companies in each segment of the supply chain were identified (e.g. farmers, primary processors, etc.); and  Primary sources of financing were identified.
Financial value-chain analysis : tuna, shrimp, soy and beef
Duijn, A.P. van; Beukers, R. ; Cowan, Roberta B. ; Judge, L.O. ; Pijl, Willem van der; Römgens, Indra ; Scheele, Fleur ; Steinweg, Tim - \ 2016
LEI Wageningen UR (Report / LEI Wageningen UR 2016-028) - 80 p.
supply chain management - agro-industrial chains - retail marketing - commodities - finance - tuna - shrimps - glycine (fabaceae) - beef - world - ketenmanagement - agro-industriële ketens - marketing voor de detailhandel - basisproducten - financiën - tonijn - garnalen - rundvlees - wereld
This study is a detailed analysis of which parts of the tuna, shrimp, soy and beef supply chains are most open to constructive engagement through financial vehicles and mechanisms. The study indentifies the largest market shares in the various supply chains. For the retail sector, the objective was to analyse the openness of the retail sector to financial influence taking into account the latest sector trends.
E2F7 and E2F8 promote angiogenesis through transcriptional activation of VEGFA in cooperation with HIF1
Weijts, B.G.M.W. ; Bakker, W.J. ; Cornelissen, P.W.A. ; Liang, K. ; Schaftenaar, F.H. ; Westendorp, B. ; Wolf, C.A.C.M.T. de; Paciejewska, M. ; Scheele, C.L.G.J. ; Kent, L. ; Leone, G. ; Schulte-Merker, S. ; Bruin, A. de - \ 2012
The EMBO Journal 31 (2012)19. - ISSN 0261-4189 - p. 3871 - 3884.
hypoxia-inducible factor-1 - growth-factor gene - embryonic-development - vascular development - o-2 homeostasis - factor 1-alpha - zebrafish - proliferation - cancer - hif-1-alpha
The E2F family of transcription factors plays an important role in controlling cell-cycle progression. While this is their best-known function, we report here novel functions for the newest members of the E2F family, E2F7 and E2F8 (E2F7/8). We show that simultaneous deletion of E2F7/8 in zebrafish and mice leads to severe vascular defects during embryonic development. Using a panel of transgenic zebrafish with fluorescent-labelled blood vessels, we demonstrate that E2F7/8 are essential for proper formation of blood vessels. Despite their classification as transcriptional repressors, we provide evidence for a molecular mechanism through which E2F7/8 activate the transcription of the vascular endothelial growth factor A (VEGFA), a key factor in guiding angiogenesis. We show that E2F7/8 directly bind and stimulate the VEGFA promoter independent of canonical E2F binding elements. Instead, E2F7/8 form a transcriptional complex with the hypoxia inducible factor 1 (HIF1) to stimulate VEGFA promoter activity. These results uncover an unexpected link between E2F7/8 and the HIF1-VEGFA pathway providing a molecular mechanism by which E2F7/8 control angiogenesis.
Kinderen leren zingend handen wassen
Hazeleger, W.C. - \ 2011
Edelman, Dettol
Ruim zestig kinderen kregen maandag 28 maart een speciale hygiëneles in het NEMO in Amsterdam. Ze leerden wat bacteriën precies zijn, waarom ze hun handen moeten wassen en hoe ze dat goed kunnen doen. Samen met kinderzanger Dirk Scheele namen ze daarna de proef op de som
Rapportage LTO FAB II 2008 : Functionele Agro Biodiversiteit
Scheele, J. ; Gurp, H. van; Alebeek, F.A.N. van; Belder, E. den; Elderson, J. - \ 2009
Tilburg : ZLTO Projecten - 91
akkerbouw - tuinbouw - biodiversiteit - plagenbestrijding - gewasteelt - monitoring - functionele biodiversiteit - akkerranden - agrobiodiversiteit - arable farming - horticulture - biodiversity - pest control - crop management - functional biodiversity - field margins - agro-biodiversity
Doel van het LTO FAB II project is een gebruiksklaar FAB concept te ontwikkelen voor een aantal ziekten en plagen in een aantal gewassen die op eenvoudige wijze door telers benut kan worden en voor de toepasser kostenneutraal zijn. Uitgangspunt in het FAB project is een evenwichtige balans tussen de 3 P’s (People, planet én profit). Het toetsen van wetenschappelijke inzichten en het genereren van nieuwe voor de praktijk toepasbare kennis is de centrale taak van dit project. Daarbij daagt FAB de wetenschap uit en worden innovaties uitgeprobeerd. In deze rapportage zijn de resultaten en conclusies verwoord voor de deelprojecten omgeving, bovengronds (akkerranden en scouting) en bodem tijdens het seizoen 2008
Ascites susceptibility as affected by dietary lysine to energy ratios in interaction with broiler genotypes
Malan, D.D. ; Scheele, C.W. ; Buyse, J. ; Kwakernaak, C. ; Klis, J.D. van der; Decuypere, E. - \ 2007
Archiv für Geflügelkunde 71 (2007)6. - ISSN 0003-9098 - p. 247 - 257.
growth-hormone-secretion - carbon-dioxide tensions - thyroid-hormone - metabolic-rate - juvenile chickens - feed restriction - growing chickens - protein content - disturbances - performance
Male chickens of two pure broiler breeder (S1 and S2) and a broiler cross line Ross 308 (BC) were reared from 0-35 days of age and were fed three dietary regimes with different lysine to apparent metabolizable energy (Lys/AME) ratios. Chickens were subjected to low ambient temperatures to stimulate the development of ascites. The objectives of the experiment was to evaluate effects of different ratios lysine to apparent metabolizable energy (Lys/AME) in diets, at different ages, on following indicators in metabolism for ascites susceptibility: arterial and venous blood gas pressures ( pa CO2, pv CO2, pa O2 and pv O2), heat production (Hp), plasma thyroid hormone concentrations (triiodothyronine, T3 and thyroxine, T4) and proportional organ weights (lung, liver and heart). Measurements were carried out at 2 and 5 wk of age. The ascites susceptible sire lines displayed, at different ages, marked higher pv CO2 and arterial pa CO2 values and lower plasma thyroid hormone concentrations compared to the less ascites susceptible BC line. The latter line showed heavier proportional lung weights (P
Rapportage FAB 2006 : Functionele Agro Biodiversiteit
Scheele, H. ; Gurp, H. van; Alebeek, F.A.N. van; Belder, E. den; Broek, R.C.F.M. van den; Buurma, J.S. ; Elderson, J. ; Meurs, E.J.J. ; Rijn, P. van; Spruijt, J. ; Vlaswinkel, M.E.T. ; Willemse, J. - \ 2007
Tilburg : LTO projecten - 148
biologische bestrijding - plantenplagen - bodembiologie - plantenziekten - bouwland - slootkanten - aardappelen - spruitjes - graansoorten - agrobiodiversiteit - biological control - plant pests - soil biology - plant diseases - arable land - ditch banks - potatoes - brussels sprouts - cereals - agro-biodiversity
Dit LTO project over functionele agrobiodiversiteit is mede gefinancierd door LNV, VROM, Hoofdproductschap Akkerbouw, Productschap Tuinbouw en Rabobank. Het bevat tekstbijdragen vanuit LEI, PRI, PPO, NIOO en DLV Plant. Het onderzoek betreft: akkerranden met bloemstroken, bodemfauana van die akkeranden, bladluizen in aardappelen, graan en spruitkool, wittelkoolvlieg en rupsen op spruitkool. Afsluitend een bedrijfseconomische bijdrage
Eindrapportage FAB 2005-2007 : functionele Agro Biodiversiteit (FAB)
Scheele, H. ; Gurp, H. van; Alebeek, F.A.N. van; Belder, E. den; Broek, R.C.F.M. van den; Buurma, J.S. ; Elderson, J. ; Rijn, P. van; Vlaswinkel, M.E.T. ; Willemse, J. - \ 2007
[Den Haag etc.] : Ministerie van LNV [etc.] - 47
biologische bestrijding - plagen - bouwland - plantenziekten - akkerbouw - slootkanten - bevordering van natuurlijke vijanden - agrobiodiversiteit - biological control - pests - arable land - plant diseases - arable farming - ditch banks - encouragement - agro-biodiversity
Het project Functionele Agro Biodiversiteit (FAB) werd in 2002 door LTO Nederland geformuleerd en ging in 2004 in de Hoeksche Waard van start. Het eerste doel was om binnen het agrarische gebied een hoge biologische diversiteit te bereiken, waardoor natuurlijke vijanden een maximale rol kunnen spelen bij de bestrijding van ziekten en plagen in de gewassen, en het gebruik van chemische middelen tot een minimum beperkt kan worden. Daarnaast is het project erop gericht om door onderzoek en praktijkervaring kennis op te doen over de manier waarop dat kan worden gerealiseerd met behoud van de productieve economische functies in het gebied. Omdat plaagdieren en hun natuurlijke vijanden zich in de ruimte bewegen waarbij dijken, bermen, watergangen, bosjes en slootkanten een remmend of juist stimulerend effect hebben, moet een dergelijk project niet op het niveau van een bedrijf maar op dat van een gebied worden gerealiseerd.
Rapportage FAB 2005 : Functionele Agro Biodiversiteit
Scheele, H. ; Gurp, H. van; Alebeek, F.A.N. van; Belder, E. den; Buurma, J.S. ; Elderson, J. ; Meurs, E.J.J. ; Rijn, P. van; Spruijt, J. ; Vlaswinkel, M.E.T. ; Willemse, J. - \ 2006
Tilburg : LTO projecten - 127 p.
Ascites and venous carbon dioxide tensions in juvenile chickens of highly selected genotypes and native strains
Scheele, C.W. ; Klis, J.D. van der; Kwakernaak, C. ; Dekker, R.A. ; Middelkoop, J.H. van; Buyse, J. ; Decuypere, E. - \ 2005
Worlds Poultry Science Journal 61 (2005)1. - ISSN 0043-9339 - p. 113 - 129.
growing broiler-chickens - characteristics predicting susceptibility - dietary-protein content - pulmonary-artery - metabolic-rate - high-altitude - hypertension - performance - hypoxia - vasoconstriction
A previous study by this group demonstrated that a high carbon dioxide tension in venous blood (pvCO2) of juvenile broiler chickens is a reliable predictor for ascites susceptibility. In a new experiment with five highly selected genetic stocks and two ascites resistant old breeds we studied levels and variability of pvCO2 within each stock at an early age. Effects of different selection traits (principally growth rate) between fast growing sire lines and slower growing dam lines and a commercial hybrid on blood gas (pCO2, pO2) tensions, pH and haematocrit in venous and arterial blood were examined at different ages and compared to values found in ascites resistant breeds. All birds were housed in floor pens in a climate controlled room and subjected to an ascites-predisposing cold environment. From each stock, 16 birds with the highest (high risk: HRc) and 16 birds with the lowest (low risk: LRc) pvCO2 values were selected at 12 days of age. These birds were marked for future blood sampling to determine changes in haematological characteristics with age and to relate these values to ascites susceptibility. At day 14, eight non-selected birds from each stock were randomly chosen for dissection to determine initial pulmonary arterial pressure index (API) values. Subsequently, all birds were allotted to 8 floor pens (13 birds per pen including two HRc and two LRc birds) per stock. Production performances from 104 birds per stock were measured from 16 to 33 days of age (feed intake (FI); feed conversion ratio (FCR); body weight (BW) at day 33). Mortality was recorded during the complete experimental period. At 5 wk of age, all HRc and LRc birds were necropsied and API values were recorded, which was used to classify the severity of the ascites syndrome. A convincing effect of pvCO2 values in juvenile chickens on API at 5 wk of age in modern lines confirmed results obtained in the previous study. At an early age, pvO2 values were much less predictive for high pulmonary pressure induced ascites at wk 5 than pvCO2 values. Hypercapnia combined with low blood pH values and followed by hypoxemia (inducing high haematocrit values) provoked a marked high incidence of ascites and high API values in modern breeds. A total absence of ascitic symptoms within native breeds corresponded with unchanged low API values during ageing from 12 to 33 days of age and with lower pCO2 values in venous and arterial blood compared to modern breeds at all ages. The pvCO2 difference (mean values) between HRc and LRc groups were similar for all modern lines irrespective of age and showed no relationship to growth rate. API, as a reliable indicator for ascites susceptibility, of modern breed chickens correlated with pvCO2 values, but not with growth rate. The high correlation between pvCO2 in juvenile chickens and API values at 5 wk of age indicated that a strong genetic selection pressure on low pvCO2 values at an early age will be an effective method to reduce decisively the occurrence of the ascites syndrome at sea level.
Metabolic rate and its relationship with ascites in chicken genotypes
Malan, D.D. ; Scheele, C.W. ; Buyse, J. ; Kwakernaak, C. ; Siebrits, F.K. ; Klis, J.D. van der; Decuypere, E. - \ 2003
British Poultry Science 44 (2003)2. - ISSN 0007-1668 - p. 309 - 315.
broiler chicken - physiological variables - ambient-temperature - growth - susceptibility - hemodynamics - performance - occlusion
This review addresses the suggestion that the decline in dairy reproductive performance, as increasingly observed these days, may be due to a hampered process of metabolic adaptation in early lactating cows. In our opinion, adaptation to the negative energy balance is a gradual process. Because almost all cows do adapt in the long run, it is not possible to classify animals as adapted or non-adapted. The use of risk factors is more appropriate in this case and is discussed in this review. Among them are the body condition score and its derivatives, feed intake, the calculated negative energy balance, and metabolic parameters like the plasma concentration of insulin or the triacylglycerol content in the liver. Moreover, factors that play a role in the link between declined reproductive performance and the metabolic situation of the cow during the early lactating period are discussed. Among these are insulin, insulin-like growth factors, leptin, neuropeptide Y, non-esterified fatty acids, thyroid hormones, urea, and ammonia.
Haematological characteristics predicting susceptibility for ascites. 2. High haematocrit values in juvenile chickens.
Scheele, C.W. ; Klis, J.D. van der; Kwakernaak, C. ; Buys, N. ; Decuypere, E. - \ 2003
British Poultry Science 44 (2003)3. - ISSN 0007-1668 - p. 484 - 489.
growing broiler-chickens - heart-failure - pulmonary-hypertension - growth-rate - mortality - parents - blood
1. Male broilers of two different genetic stocks, a pure broiler sire line (A) and commercially available Ross broilers (B), were used to study the effect of differences in haematocrit values in 12-d-old chickens on the development of ascitic symptoms. Body weight gain (BWG), feed intake (FI) and feed conversion ratio (FRC) were measured from 2 to 5 weeks of age. Mortality was recorded from 2 to 6 weeks. The birds were kept at a low ambient temperature to stimulate the incidence of ascites. 2. From each stock 32 birds with the highest (High Ht) and 32 birds with the lowest (Low Ht) haematocrit values in venous blood were selected at 12 d of age for an examination on susceptibility for the ascites syndrome at 5 weeks. 3. At 2 weeks 448 birds per stock (including High Ht and Low Ht birds) were allotted to 32 floor pens (1 High Ht and 1 Low Ht in each pen). Venous blood samples were taken weekly in High Ht and Low Ht birds for haematocrit measurements and at week 5 also thyroid hormone (T3, T4) concentrations in plasma were measured. At 5 weeks all High Ht and Low Ht birds were examined post-mortem and arterial pressure index, heart weight, lung weight and liver weight (all relative to body weight) were recorded. High values for arterial pressure index, relative heart and liver weights and low values for relative lung weights and plasma thyroid hormone were considered to be indicators for ascites susceptibility. 4. Stock A, with the highest ascites mortality, had lower values for BWG and FCR than stock B. Throughout, a clear difference in Ht values between High Ht and Low Ht birds was maintained. No significant effects of 12-d haematocrit values were found on the incidence of ascitic symptoms until week 5. High Ht values tended to correlate with low relative lung weights and low plasma T3 concentrations in High Ht birds. 5. Within the groups of selected birds, there was an effect of stock on ascitic symptoms (arterial pressure index, relative heart weight and T3 values) at week 5. This is consistent with a higher ascites mortality in flock A than in flock B, over the whole period up to 6 weeks. Until 4 weeks both A and B were similar with respect to mean Ht values of High Ht and Low Ht groups. After 4 weeks Ht values were very high in the High Ht birds of stock A, possibly as a result of the susceptibility for ascites of stock A. There was a significant interaction between stock and Ht values on the ascites-related variable arterial pressure index. Only in stock A was high arterial pressure at 5 weeks related to high Ht values at d 12. 6. Overall it was concluded that a high Ht in blood of juvenile chickens has limited practical value in predicting incidence of ascites at 5 weeks of age.
Haematological characteristics predicting susceptibility for ascites. 1. High carbon dioxide tensions in juvenile chickens.
Scheele, C.W. ; Klis, J.D. van der; Kwakernaak, C. ; Buys, N. ; Decuypere, E. - \ 2003
British Poultry Science 44 (2003)3. - ISSN 0007-1668 - p. 476 - 483.
pulmonary-hypertension syndrome - growing broiler-chickens - heart-failure - mitochondrial dysfunction - physiological variables - cardiac-arrhythmias - ambient-temperature - growth-rate - disturbances - performance
1. Male broilers of two different genetic stocks, a pure broiler sire line (A) and commercially available Ross broilers (B), were used to study the effect of haematological characteristics in juvenile chickens on the development of clinical ascitic signs. Production performance (body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR)) from 448 birds per stock was measured from 2 to 5 weeks of age. Mortality was recorded from 2 to 6 weeks of age. The birds were housed at a low ambient temperature to stimulate the incidence of ascites. 2. From each stock, 32 birds with the highest (high risk: HRc) and 32 birds with the lowest (low risk: LRc) carbon dioxide tensions (pCO2) in venous blood were selected at 11 d of age. These birds were marked for future blood sampling to determine changes in pCO2 with age to relate these values to ascites susceptibility. 3. At 2 weeks of age all birds (including HRc and LRc birds) were allotted to 32 floor pens (one HRc and one LRc in each pen) per stock. Venous blood samples were collected weekly from HRc and LRc birds for blood gas analysis and haematocrit, and at week 5 also for thyroid hormone (T3, T4) concentrations in plasma. At 5 weeks of age all HRc and LRc birds were examined post-mortem, relative heart, lung, and liver weights and arterial pressure index (API) values were recorded. 4. Birds from stock A showed a lower BWG and FCR and notably higher ascites mortality compared with stock B. An effect of pCO2 tensions at d 11 was found on the incidence of ascitic signs in selected birds of both stocks up to week 5. From the HRc groups 30% of the birds showed ascitic signs, whereas this was only 8% in the LRc group. LRc birds of stock B in particular showed constant low API values (20 +/- 3%) and none of these birds showed signs of ascites. 5. Our results suggest that the ascites problem in Ross birds can be eliminated by selection for low pCO2 tensions in venous blood. Stock effects on API, liver weight, lung weight, and plasma thyroid hormone independent of pCO2 showed a more complex picture of the ascitic signs in stock A compared with B. 6. We concluded that in this experiment a high pCO2 tension in venous blood measured at d 11 was a reliable predictor for ascites susceptibility observed at 5 weeks of age. A low pCO2 tension provides an appropriate criterion for genetic selection, whereas a high pCO2 tension emphasises the necessity for intensive management in poultry houses.
Effect of Rhizobium inoculation and phosphorus application on native Texas legumes grown in local soil
Osman, E. ; Muir, J.P. ; Elgersma, A. - \ 2002
Journal of Plant Nutrition 25 (2002). - ISSN 0190-4167 - p. 75 - 92.
Greenhouse experiments were conducted to determine the effects of Rhizobium inoculation and addition of phosphorus to soil on the productivity and quality of the Texas range legumes Desmanthus illinoiensis (Michx.) MacMill. ex B.L. Rob. & Fernald, Desmanthus velutinus Scheele, Desmanthus virgatus (L.) Willd., and Neptunia lutea (Leavenw.) Benth. Phosphorus (P) fertilization was applied at 0, 40, 80, and 120 kg P ha-1 in Experiment 1 with half the pots also receiving D522-1/2 (a Desmanthus isolate). Experiment 2 consisted only the Desmanthus species and tested four different inoculant treatments (uninoculated control, inoculated with commercial cowpea Rhizobia, D522-1/2 from Desmanthus isolates, and L1145, a Leucaena isolate). Two soil treatments were used in Experiment 2, gamma radiation sterilized and unsterilized soil, to determine whether introduced Rhizobia were as effective as native populations. Shoot dry matter (DM) yield, root DM weight, and shoot nitrogen (N) and P concentration increased with increasing P application levels up to 80 kg P ha-1. Rhizobium strain D522-1/2 was an effective inoculant for all legumes when applied in combination with P fertilizer (Experiment 1). In sterilized P-deficient soil (Experiment 2), inoculation improved the parameters measured. In unsterilized soil, however, only D522-1/2 and L1145 improved shoot nitrogen concentration while the cowpea Rhizobium strain was detrimental in the case of D. velutinus. The low concentration of available soil P and the scarcity of active Rhizobium in the soil might be the cause of the slow establishment of native legume species in disturbed soils without native Rhizobia populations.
De invloed van isoflavonen in het voer op de fytaat-fosfor afbraak en de immuunstatus van vleeskuikens
Versteegh, H.A.J. ; Jeurissen, S.H.M. ; Scheele, C.W. ; Klis, J.D. van der - \ 2001
Lelystad : ID-Lelystad
Validatie van een nieuwe netto energieformule voor pluimvee
Scheele, C.W. ; Dekker, R.A. ; Klis, J.D. van der; Kwakkel, R.P. ; Verstegen, M.W.A. - \ 2001
Lelystad : ID-Lelystad - 53 p.
Towards a more sustainable weed management in the Netherlands: policy and challenges for weed research
Lotz, L.A.P. ; Stelt-Scheele, D.D. van der; Weide, R.Y. van der - \ 2000
In: Proceedings, 52nd International Symposium on Crop Protection, Gent, Belgium, 9 May 2000, Part I. Mededelingen Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen, Universiteit Gent. 2000, 65: 2a - p. 7 - 15.
Vitale vleeskuikens door aangepast ketenmanagement en genetica
Middelkoop, J.H. van; Scheele, C.W. - \ 1999
Praktijkonderzoek voor de Pluimveehouderij 10 (1999)3. - ISSN 0924-9087 - p. 17 - 20.
vleeskuikens - diergezondheid - stofwisselingsstoornissen - genetica - groei - ontwikkeling - dierenwelzijn - voer - samenstelling - voedingswaarde - bedrijfsvoering - broilers - animal health - metabolic disorders - genetics - growth - development - animal welfare - feeds - composition - nutritive value - management
Het project Vitale vleeskuikens is een goed voorbeeld van een ketensamenwerkingsproject om de door de sector en maatschappij ervaren verminderde vitaliteit van vleeskuikens in de productieketen op te lossen.
High carbon dioxide tension (PCO2) and the incidence of cardiac arrhythmias in rapidly growing broiler chickens
Korte, S.M. ; Sgoifo, A. ; Ruesink, W. ; Kwakernaak, C. ; Voorst, S. van; Scheele, C.W. ; Blokhuis, H.J. - \ 1999
Veterinary Record 145 (1999)2. - ISSN 0042-4900 - p. 40 - 43.
Performance and physiological variables in broiler chicken lines differing in susceptibility to the ascites syndrome: 1. Changes in blood gases as a function of ambient temperature
Buys, N. ; Scheele, C.W. ; Kwakernaak, C. ; Klis, J.D. van der; Decuypere, E. - \ 1999
British Poultry Science 40 (1999)1. - ISSN 0007-1668 - p. 135 - 139.
1. Male broilers of 5 genetic stocks (A, B, C, D, E) selected in different ways for fast growth and low food conversion ratio (FCR) and differing in ascites sensitivity were subjected to 2 different ambient temperature step down regimens: high temperature (HT: 33 to 20°C over 33 d) and low temperature (LT: 30 to 15°C over 17 d). 2. Ascites incidence was recorded daily. Food intake and body weight gain were measured weekly and FCR was calculated. Heat production (Hp) was calculated using the comparative slaughter method. At 28 d venous samples were taken for blood gas analysis and haematocrit and relative heart, lung and liver weights were recorded. 3. Populations A and C showed the highest growth rates combined with a low FCR and a higher ascites incidence. A low FCR in these stocks was attributable to low values for Hp. These stocks also had low pO2 and high pCO2 in venous blood at low ambient temperature compared with other stocks. Stock B, which exhibited the slowest growth rate and the highest FCR, was not susceptible to ascites and showed higher Hp and pO2 and pCO2 at low ambient temperature. Populations D and E were intermediate for almost all variables. Heart and lung weights were both increased at LT, while liver weight did not differ between temperature regimes. 4. Our results show that a high haematocrit is not necessarily linked with an increased susceptibility to ascites.
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