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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    Screening of white-rot fungi for bioprocessing of wheat straw into ruminant feed
    Nayan, N. ; Sonnenberg, A.S.M. ; Hendriks, W.H. ; Cone, J.W. - \ 2018
    Journal of Applied Microbiology 125 (2018)2. - ISSN 1364-5072 - p. 468 - 479.
    degradability - different strains/species - in vitro gas production - ruminant - screening - wheat straw - white-rot fungi

    Aim: In this study, the biological variation for improvement of the nutritive value of wheat straw by 12 Ceriporiopsis subvermispora, 10 Pleurotus eryngii and 10 Lentinula edodes strains was assessed. Screening of the best performing strains within each species was made based on the in vitro degradability of fungal-treated wheat straw. Methods and Results: Wheat straw was inoculated with each strain for 7 weeks of solid state fermentation. Weekly samples were evaluated for in vitro gas production (IVGP) in buffered rumen fluid for 72 h. Out of the 32 fungal strains studied, 17 strains showed a significantly higher (P < 0·05) IVGP compared to the control after 7 weeks (227·7 ml g−1 OM). The three best Ceriporiopsis subvermispora strains showed a mean IVGP of 297·0 ml g−1 OM, while the three best P. eryngii and L. edodes strains showed a mean IVGP of 257·8 and 291·5 ml g−1 OM, respectively. Conclusion: Ceriporiopsis subvermispora strains show an overall high potential to improve the ruminal degradability of wheat straw, followed by L. edodes and P. eryngii strains. Significance and Impact of the Study: Large variation exists within and among different fungal species in the valorization of wheat straw, which offers opportunities to improve the fungal genotype by breeding.

    Estimation of the in situ degradation of the washout fraction of starch by using a modified in situ protocol and in vitro measurements
    Jonge, L.H. de; Laar, H. van; Dijkstra, J. - \ 2015
    Animal 9 (2015)9. - ISSN 1751-7311 - p. 1465 - 1472.
    dairy-cows - digestion - rumen - gas - degradability - barley - vivo - digestibility - feedstuff - cultivars
    The in situ degradation of the washout fraction of starch in six feed ingredients (i.e. barley, faba beans, maize, oats, peas and wheat) was studied by using a modified in situ protocol and in vitro measurements. In comparison with the washing machine method, the modified protocol comprises a milder rinsing method to reduce particulate loss during rinsing. The modified method markedly reduced the average washout fraction of starch in these products from 0.333 to 0.042 g/g. Applying the modified rinsing method, the fractional degradation rate (k d ) of starch in barley, oats and wheat decreased from on average 0.327 to 0.144 h-1 whereas for faba beans, peas and maize no differences in k d were observed compared with the traditional washing machine rinsing. For barley, maize and wheat, the difference in non-fermented starch in the residue between both rinsing methods during the first 4 h of incubation increased, which indicates secondary particle loss. The average effective degradation of starch decreased from 0.761 to 0.572 g/g when using the new rinsing method and to 0.494 g/g when applying a correction for particulate matter loss during incubation. The in vitro k d of starch in the non-washout fraction did not differ from that in the total product. The calculated ratio between the k d of starch in the washout and non-washout fraction was on average 1.59 and varied between 0.96 for oats and 2.39 for maize. The fractional rate of gas production was significantly different between the total product and the non-washout fraction. For all products, except oats, this rate of gas production was larger for the total product compared with the non-washout fraction whereas for oats the opposite was observed. The rate of increase in gas production was, especially for grains, strongly correlated with the in vitro k d of starch. The results of the present study do not support the assumption used in several feed evaluation systems that the degradation of the washout fraction of starch in the rumen is much faster than that of the non-washout fraction.
    A new approach to estimate the in situ fractional degradation rate of organic matter and nitrogen in wheat yeast concentrates
    Jonge, L.H. de; Laar, H. van; Hendriks, W.H. ; Dijkstra, J. - \ 2015
    Animal 9 (2015)3. - ISSN 1751-7311 - p. 437 - 444.
    rumen - degradability - feedstuff - protein
    In the classic in situ method, small particles are removed during rinsing and hence their fractional degradation rate cannot be determined. A new approach was developed to estimate the fractional degradation rate of nutrients in small particles. This approach was based on an alternative rinsing method to reduce the particulate matter loss during rinsing and on quantifying the particulate matter loss that occurs during incubation in the rumen itself. To quantify particulate matter loss during incubation, loss of small particles during the in situ incubation was studied using undegradable silica with different particle sizes. Particulate matter loss during incubation was limited to particles smaller than ~40 µm with a mean fractional particulate matter loss rate of 0.035 h-1 (first experiment) and 0.073 h-1 (second experiment) and an undegradable fraction of 0.001 and 0.050, respectively. In the second experiment, the fractional particulate matter loss rate after rinsing in a water bath at 50 strokes per minute (s.p.m.) (0.215 h-1) and the undegradable fraction at 20 s.p.m. (0.461) were significantly larger than that upon incubation in the rumen, whereas the fractional particulate matter loss rate (0.140 and 0.087 h-1, respectively) and the undegradable fraction (0.330 and 0.075, respectively) after rinsing at 30 and 40 s.p.m. did not differ with that upon rumen incubation. This new approach was applied to estimate the in situ fractional degradation rate of insoluble organic matter (OM) and insoluble nitrogen (N) in three different wheat yeast concentrates (WYC). These WYC were characterised by a high fraction of small particles and estimating their fractional degradation rate was not possible using the traditional washing machine rinsing method. The new rinsing method increased the mean non-washout fraction of OM and N in these products from 0.113 and 0.084 (washing machine method) to 0.670 and 0.782, respectively. The mean effective degradation (ED) without correction for particulate matter loss of OM and of N was 0.714 and 0.601, respectively, and significant differences were observed between the WYC products. Applying the correction for particulate matter loss reduced the mean ED of OM to 0.676 (30 s.p.m.) and 0.477 (40 s.p.m.), and reduced the mean ED of N to 0.475 (30 s.p.m.) and 0.328 (40 s.p.m.). These marked reductions in fractional degradation rate upon correction for small particulate matter loss emphasised the pronounced effect of correction for undegraded particulate matter loss on the fractional disappearance rates of OM and N in WYC products.
    Relationship between chemical composition and in situ rumen degradation characteristics of grass silages in dairy cows
    Ali, M. ; Cone, J.W. ; Duinkerken, G. van; Klop, A. ; Kruisdijk, J. ; Blok, M.C. ; Bruinenberg, M.H. ; Hendriks, W.H. - \ 2014
    NJAS Wageningen Journal of Life Sciences 70-71 (2014). - ISSN 1573-5214 - p. 9 - 15.
    neutral detergent fiber - dry-matter - crude protein - intestinal digestibility - degradability - forages - prediction - supplementation - cattle - sacco
    The DVE/OEB2010 system in the Netherlands uses a large database of in situ rumen incubations with grass silage and grass hay samples to derive prediction formulas to estimate the rumen degradation characteristics of a number of feed value parameters. These in situ rumen incubations were not performed for this specific purpose and the data were generated at different research institutes over more than 40 years, using different grass management and fertilization practices and using different protocols. The objectives of this study were to 1) generate a new database on the rumen degradability of dry matter (DM), organic matter (OM), crude protein (CP) and neutral detergent fibre (NDF) of grass silages, 2) compare this new database with the old database used in the DVE/OEB2010 system, and 3) derive regression equations using the new database to investigate the relationships between chemical composition and in situ ruminal degradation characteristics of DM, OM, CP and NDF of the grass silages. Sixty nine grass silages, with a broad range in chemical composition and quality parameters, were selected and incubated using the nylon bag technique in the rumen of three lactating Holstein Friesian cows for 2, 4, 8, 16, 32, 72 and 336 h. There was a large range in the rumen degradable fractions of DM, OM, CP and NDF of the grass silages at each rumen incubation period. The data on the rumen degradation characteristics of DM, OM, CP and NDF in the present study were determined using the same standard incubation protocol, the same cows, and the same chemical analysis procedures for all the grass silage samples. Regression analysis, using the new database, showed relationships between the washable (W) fraction, rumen undegradable (U) fraction, potentially rumen degradable (D) fraction and effective rumen degradation (ED) of DM, OM, CP and NDF, respectively, and the chemical composition of the grass silages.
    Relationship between chemical composition and in situ rumen degradation characteristics of maize silages in dairy cows
    Ali, M. ; Duinkerken, G. van; Cone, J.W. ; Klop, A. ; Blok, M.C. ; Spek, J.W. ; Bruinenberg, M.H. ; Hendriks, W.H. - \ 2014
    Animal 8 (2014)11. - ISSN 1751-7311 - p. 1832 - 1838.
    neutral detergent fiber - crude protein - starch degradation - dry-matter - degradability - maturity - digestibility - vitro - digestion - extent
    Several in situ studies have been conducted on maize silages to determine the effect of individual factors such as maturity stage, chop length and ensiling of maize crop on the rumen degradation but the information on the relationship between chemical composition and in situ rumen degradation characteristics remains scarce. The objectives of this study were to determine and describe relationships between the chemical composition and the rumen degradation characteristics of dry matter (DM), organic matter (OM), CP, starch and aNDFom (NDF assayed with a heat stable amylase and expressed exclusive of residual ash) of maize silages. In all, 75 maize silage samples were selected, with a broad range in chemical composition and quality parameters. The samples were incubated in the rumen for 2, 4, 8, 16, 32, 72 and 336 h, using the nylon bag technique. Large range was found in the rumen degradable fractions of DM, OM, CP, starch and aNDFom because of the broad range in chemical composition and quality parameters. The new database with in situ rumen degradation characteristics of DM, OM, CP, starch and aNDFom of the maize silages was obtained under uniform experimental conditions; same cows, same incubation protocol and same chemical analysis procedures. Regression equations were developed with significant predictors (P
    Oven-drying reduces ruminal starch degradation in maize kernels
    Ali, M. ; Cone, J.W. ; Hendriks, W.H. ; Struik, P.C. - \ 2014
    Animal Feed Science and Technology 193 (2014). - ISSN 0377-8401 - p. 44 - 50.
    physicochemical properties - microwave irradiation - gas-production - rumen fluid - corn-silage - digestibility - grain - degradability - moisture - protein
    The degradation of starch largely determines the feeding value of maize (Zea mays L.) for dairy cows. Normally, maize kernels are dried and ground before chemical analysis and determining degradation characteristics, whereas cows eat and digest fresh material. Drying the moist maize kernels (consisting mainly of starch) at high temperatures can influence their physical properties and thus their degradation dynamics in the rumen. We compared the in vitro degradability of dried maize kernels with that of fresh kernels after incubation in rumen fluid. Maize kernels were obtained from genotypes diverse in starch structure, composition and type of endosperm. These genotypes were grown in greenhouses at different temperatures during starch accumulation, and harvested at different maturity stages, in two experiments. Starch content was assessed using the amyloglucosidase method. Fermentation in rumen fluid was measured using an in vitro gas production technique. Starch degradation of the kernels was calculated after 6, 12 and 20 h of incubation in rumen fluid. Oven-drying influenced (P <0.0001) the in vitro degradation of starch in maize kernels at the different incubation times, with more starch being degraded in the fresh than in the oven-dried maize kernels, although the differences were small (11–15%). There was a consistent interaction (P <0.009 to 0.0002) between oven-drying and genotype, with the high-amylose genotype showing larger effects of oven-drying than the other genotypes. The vitreous genotype showed a lower starch degradation than the non-vitreous type. At earlier maturity stages, the difference between oven-dried and fresh kernels was larger than at later maturity stages. The temperature during grain filling affected (P <0.0001) starch degradation but did not affect the difference between fresh and oven-dried samples. Oven-drying reduced the in vitro rumen starch degradation of maize kernels regardless of growing conditions, genotype and maturity stage, but its effect depends on genotype and maturity.
    Chemical composition and in vitro total gas and methane production of forage species from the Mid Rift Valley grasslands of Ethiopia
    Bezabih, M. ; Pellikaan, W.F. ; Tolera, A. ; Khan, N.A. ; Hendriks, W.H. - \ 2014
    Grass and Forage Science 69 (2014)4. - ISSN 0142-5242 - p. 635 - 643.
    feed-intake - production profiles - southern ethiopia - detergent fiber - ruminant feeds - zebu cattle - rumen fluid - fermentation - protein - degradability
    There is increasing interest in sustainable land use in the tropics to optimize animal production while also reducing methane (CH4) emissions, but information on nutritive value and CH4-emission potential of tropical forage species is limited. Samples of 24 grasses and five other forages were collected during the main rainy season on randomly positioned quadrats in semi-arid grassland in the Mid Rift Valley of Ethiopia. Samples were pooled by species, analysed for chemical composition and incubated with rumen fluid to determine total gas and CH4-emission potentials using a fully automated in vitro gas production apparatus. Organic matter digestibility (OMD) and metabolizable energy (ME) contents were calculated from chemical composition and gas production data. Large variability was observed among forages for all nutritional variables considered. The grasses Eleusine multiflora, Pennisetum stramineum, Dactyloctenium aegyptium, Eragrostis aspera, Cenchrus ciliaris and Eragrostis cilianensis showed relatively high OMD (68–72%) and ME values (9 1– 10 2 MJ kg 1 dry matter). Melinis repens, E. multiflora and the non-legume forb Zaleya pentandra showed relatively low CH4 to total gas ratios; these species may have potential for use in low CH4-emission forage diets. Acacia tortilis fruits had high content of crude protein and moderate ME values, and may be an ideal feed supplement for the grazing ruminant. Sodium content was below the recommended level for ruminants in all the forage species. Overall, the pasture stand during the main growing season was evaluated as having moderate nutritional quality.
    A modified rinsing method for the determination of the S, W-S and D + U fraction of protein and starch in feedstuff within the in situ technique
    Jonge, L.H. de; Laar, H. van; Hendriks, W.H. ; Dijkstra, J. - \ 2013
    Animal 7 (2013)8. - ISSN 1751-7311 - p. 1289 - 1297.
    rumen - degradability - degradation - electrophoresis - ruminants - profiles - extent - sacco
    A modified rinsing method for the in situ technique was developed to separate, isolate and characterise the soluble (S), the insoluble washout (W–S) and the non-washout fractions (D1U) within one procedure. For non-incubated bags ( t50 h), this method was compared with the conventional, Combined Fractionation (CF) method that measures the D1U and S fractions in separate steps and subsequently calculates the W–S fraction. The modified method was based on rinsing of nylon bags in a closed vessel containing a buffer solution (pH 6.2) during 1 h, where shaking speeds of 40, 100, and 160 strokes per minutes (spm) were evaluated, and tested for six feed ingredients (faba beans, maize, oats, peas, soya beans and wheat) and four forages (two ryegrass silages and two maize silages). The average recoveries as the sum of all fractions were 0.97260.041 for N and 0.99060.050 for starch (mean6s.d.). The mean W–S fraction increased with increasing shaking speed and varied between 0.017 (N) and 0.083 (starch) at 40 spm and 0.078 (N) and 0.303 (starch) at 160 spm, respectively. For ryegrass silages, the W–S fraction was absent at all shaking speeds, but was present in the CF method. The modified method, in particular at 40 and 100 spm, reduced the loss of small particles during rinsing, resulting in lower W–S and higher D1U fractions for N and starch compared with the CF method. For soya beans and ryegrass silage, the modified method reduced the S fraction of N compared with the CF method. The results obtained at 160 spm showed the best comparison with those from the CF method. The W–S fraction of the feedstuff obtained at 160 spm contained mainly particles smaller than 40 mm (0.90860.086). In most feedstuff, starch was the most abundant chemical component in the W–S fraction and its content (726675 g/kg DM) was higher than in the D1U fraction (4056177 g/kg DM). Alkaline-soluble proteins were the dominant N-containing components in the W–S fraction of dry feed ingredients and its relative content (0.7960.18 of total N in W–S) was higher than in the D1U fraction (0.5960.07 of total N in D1U) for all feedstuff except maize. The molecular weight distribution of the alkaline-soluble proteins differed between the W–S and the D1U fractions of all dry feed ingredients, except soya beans and wheat.
    Interaction between dietary content of protein and sodium chloride on milk urea concentration, urinary urea excretion, renal recycling of urea, and urea transfer to the gastrointestinal tract in dairy cows
    Spek, J.W. ; Bannink, A. ; Gort, G. ; Hendriks, W.H. ; Dijkstra, J. - \ 2013
    Journal of Dairy Science 96 (2013)9. - ISSN 0022-0302 - p. 5734 - 5745.
    fed grass-silage - ammonia emissions - nitrogen-excretion - holstein cows - cattle - metabolism - sheep - rumen - plasma - degradability
    Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl) intake separately, and their interaction, on MUN and UUN, on the relationship between UUN and MUN, on renal recycling of urea, and on urea transfer to the gastrointestinal tract. Twelve second-parity cows (body weight of 645±37kg, 146±29d in milk, and a milk production of 34.0±3.28kg/d), of which 8 were previously fitted with a rumen cannula, were fitted with catheters in the urine bladder and jugular vein. The experiment had a split-plot arrangement with dietary crude protein (CP) content as the main plot factor [116 and 154g of CP/kg of dry matter (DM)] and dietary NaCl content as the subplot factor (3.1 and 13.5g of Na/kg of DM). Cows were fed at 95% of the average ad libitum feed intake of cows receiving the low protein diets. Average MUN and UUN were, respectively, 3.90mg of N/dL and 45g of N/d higher for the high protein diets compared with the low protein diets. Compared with the low NaCl diets, MUN was, on average, 1.74mg of N/dL lower for the high NaCl diets, whereas UUN was unaffected. We found no interaction between dietary content of protein and NaCl on performance characteristics or on MUN, UUN, urine production, and renal clearance characteristics. The creatinine clearance rate was not affected by dietary content of protein and NaCl. Urea transfer to the gastrointestinal tract, expressed as a fraction of plasma urea entry rate, was negatively related to dietary protein, whereas it was not affected by dietary NaCl content. We found no interaction between dietary protein and NaCl content on plasma urea entry rate and gastrointestinal urea entry rate or their ratio. The relationship between MUN and UUN was significantly affected by the class variable dietary NaCl content: UUN=-17.7±7.24 + 10.09±1.016 × MUN + 2.26±0.729 × MUN (for high NaCl); R(2)=0.85. Removal of the MUN × NaCl interaction term lowered the coefficient of determination from 0.85 to 0.77. In conclusion, dietary protein content is positively related to MUN and UUN, whereas dietary NaCl content is negatively correlated to MUN but NaCl content is not related to UUN. We found no interaction between dietary protein and NaCl content on performance, MUN, UUN, or renal urea recycling, nor on plasma urea entry rate and urea transfer to the gastrointestinal tract. For a proper interpretation of the relationship between MUN and UUN, the effect of dietary NaCl should be taken into account, but we found no evidence that the effect of dietary NaCl on MUN is dependent on dietary protein content.
    Assessment of Grewia oppositifolia leaves as crude protein supplement to low-quality forage diets of sheep
    Khan, N.A. ; Habib, G. - \ 2012
    Tropical Animal Health and Production 44 (2012)7. - ISSN 0049-4747 - p. 1375 - 1381.
    tree leaves - northern grasslands - nutrient digestion - detergent fiber - pakistan - feed - degradability - rangeland - rumen
    In the tropical arid and semi-arid regions of many developing countries, sheep are predominantly grazed on low-quality pastures and stall-fed on crop residues. This study evaluated the potential of Grewia oppositifolia tree leaves as crude protein (CP) supplement to the low-quality diets of sheep in comparison with cottonseed cake (CSC). Changes in the chemical composition of the leaves with progressive maturation (December to March) were studied. The leaves maintained a high CP content (> 164 g/kg dry matter (DM)) during the prolonged maturation in the winter feed scarcity period. The leaves were rich in Ca (41 g/kg DM) and K (89 g/kg DM). The rate of degradation and effective degradability of CP were consistently higher (P <0.001) in CSC than in G. oppositifolia. A balance trial in a 4 x 4 Latin square design with four mature Ramghani wethers showed that DM intake, DM and CP digestibility, and N retention did not differ with the substitution of CSC with G. oppositifolia leaves, as a supplement to a basal diet of sorghum hay. Body weight (BW) gain and wool yield responses to the supplements were examined with 36 lambs (27 +/- 3 kg BW; age 11 +/- 1 months) for 15 weeks. The lambs were only grazed on local pasture (control group) or supplemented with CSC, G. oppositifolia leaves, and their mixture on iso-N basis. Addition of the supplements increased (P <0.05) BW gain and wool yield, and the leaves were as effective as CSC. These results demonstrated that G. oppositifolia leaves provide good quality green fodder during the prolonged winter feed scarcity period, and that the leaves can be efficiently utilized as a CP supplement to the low-quality diets of sheep.
    Rumen degradation of oil palm fronds is improved through pre-digestion with white rot fungi but not through supplementation with yeast or enzymes
    Hassim, H.A. ; Lourenco, M. ; Goh, Y.M. ; Baars, J.J.P. ; Fievez, V. - \ 2012
    Canadian Journal of Animal Science 92 (2012)1. - ISSN 0008-3984 - p. 79 - 87.
    vitro fermentation characteristics - in-vitro - rice straw - chemical-composition - fibrolytic enzymes - wheat-straw - metabolism - degradability - digestibility - culture
    Rumen fermentation kinetics of oil palm fronds (OPF) supplemented or not with enzymes (Hemicell® or Allzyme SSF®) or yeasts (Levucell®SC or Yea-Sacc®) were studied through an in vitro gas production test (96 h) (exp. 1). In exp. 2, enzymes were supplemented to OPF pre-treated during 3 or 9 wk with either one of five white rot fungi strains. Yeasts and enzymes were tested both in active and inactive forms, which revealed the most appropriate set-up to distinguish between the rate of supplements as direct contributors to the fermentation substrate vs. stimulators of the fermentation of the basal substrate. In exp 1, addition of active and inactive Yea-Sacc® increased the apparently rumen degradable carbohydrates (ARDC) by 11%, whereas enzymes did not affect rumen degradability of non-inoculated OPF. Neither yeast nor enzymes influenced the rate of gas production of non-inoculated OPF, except for active Hemicell® at the low dose. In exp. 2, inoculation of OPF with Ceriporiopsis subvermispora for 3 wk and Lentinula edodes for 9 wk increased ARDC, but additional enzyme supplementation did not further improve ARDC or the rate of gas production.
    Fermentation kinetics and production of volatile fatty acids and microbial protein by starchy feedstuffs
    Cone, J.W. ; Becker, P.M. - \ 2012
    Animal Feed Science and Technology 172 (2012)1-2. - ISSN 0377-8401 - p. 34 - 41.
    gas-production technique - rumen fluid - production profiles - ruminant feeds - dairy-cows - milk-yield - in-situ - degradability - degradation - sheep
    The rate and extent of rumen fermentation of different starch sources can be very different, depending on the origin of the starch, but more importantly on the technological treatment of the starchy feed ingredients. Therefore, feeding different starchy feed ingredients can contribute in a very different way to the total volatile fatty acid (VFA) production in the rumen, the proportion of each VFA, and the non-glucogenic to glucogenic ratio (NGR). For 14 different starchy feed ingredients, the in vitro fermentation characteristics were determined using the gas production technique. Highest rate and extent of gas production was seen for the popped feedstuffs, while lowest was seen for the native starch sources maize and potato. This was also reflected in the rate of production of individual and total VFA. However, after 12 h of fermentation, differences in VFA content decreased and VFA production reflected the total fermentation of the organic matter. It proved that for the determined incubation periods (4, 8 and 12 h), there was a negative linear relationship (R2 = 0.33–0.79) between NGR and the amount of gas produced. There was also a negative linear relationship (R2 = 0.75) between the synthesized amount of microbial protein and the rate of fermentation at the incubation period at which the substrate was just exhausted (tRmax2). This shows that fast fermenting substrates resulted in a higher amount of microbial protein than slowly fermenting substrates. Consequently, there was also a negative linear relationship (R2 = 0.64) between the amount of microbial protein and NGR at tRmax2. It is concluded that fast fermenting starchy feedstuffs resulted in higher amounts of microbial protein in the rumen and a more glucogenic fermentation pattern, higher values of propionic acid and lower values of acetic acid and butyric acid. Abbreviations - A1, gas production caused by fermentation of the soluble fraction; A2, gas production caused by fermentation of the non-soluble fraction; B2, time needed for 0.5 of A2; C2, parameter determining the shape of the gas production sub-curve caused by fermentation of the non-soluble fraction; DM, dry matter; HAc, acetic acid; HB, butyric acid; HP, propionic acid; MP, microbial protein; NGR, non-glucogenic to glucogenic ratio; OM, organic matter; R2, fractional rate of substrate fermentation of the non-soluble fraction; RNA, ribonucleic acid; SD, standard deviation; tRmax2, time at which R2 is at its maximum; VFA, volatile fatty acids
    In situ ruminal degradation of phytic acid in formaldehyde treated rice bran
    Martin-Tereso, J. ; Gonzalez, A. ; Laar, H. van; Burbara, C. ; Pedrosa, M. ; Mulder, K. ; Hartog, L.A. den; Verstegen, M.W.A. - \ 2009
    Animal Feed Science and Technology 152 (2009)3-4. - ISSN 0377-8401 - p. 286 - 297.
    neutral detergent fiber - rapeseed meal - soybean-meal - phytate phosphorus - rumen - protein - degradability - disappearance - feedstuffs - quality
    Rice bran has a very high content of phytic acid (IP6), which is a nutritional antagonist of Ca. Microbial phytase degrades IP6, but ruminal degradation of nutrients can be reduced by formaldehyde treatment. Milk fever in dairy cows can be prevented by reducing available dietary Ca to stimulate Ca homeostasis. In the present study, effects of formaldehyde treatment on ruminal degradation of IP6 in rice bran were investigated. Two samples of full-fat rice bran were treated with four levels of formaldehyde (i.e., 0, 1000, 2500 and 5000 ppm fresh weight) and ruminally incubated in situ for 0, 4, 8, 16, 32, 64 and 336 h in three rumen fistulated lactating dairy cows. Dry matter (DM) disappearance was determined, residues were analysed for P and, for one of the products, also for inositol phosphate (IP) forms. Degradation parameters were calculated for DM, P, total IP, and IP6. The in situ washable fraction (W), undegradable fraction (U) and degradable fraction (D) were measured and the rate of degradation (kd) was calculated by exponential regression to the equation: Y(t) = U + D × exp(-kd × t). HPLC analyses confirmed that most P in the original sample and residues was phytate, mostly IP6. DM and P degraded differently in the two rice brans and formaldehyde treatment reduced degradability, lowering W and increasing D and kd. The calculated rumen escape (kp = 0.05/h) for P increased from 0.082 at 0 ppm to 0.136, 0.284 and 0.398 at 1000, 2500 and 5000 ppm of formaldehyde treatment, respectively. Degradation of total IP forms and IP6 corresponded with P disappearance. Formaldehyde treatment reduced W in total IP and IP6, proportionally increasing D, while U was 0 in both. kd decreased with formaldehyde treatment in total IP and IP6, which decreased from 0.309/h at 0 ppm to 0.217, 0.116 and 0.071%/h as formaldehyde treatment level increased. The calculated rumen escape (kp = 0.05/h) of IP6 were 0.079, 0.126, 0.229 and 0.318 for the increasing formaldehyde treatment levels. Formaldehyde treatment reduced rumen degradability of IP6 in rice bran. One kg of formaldehyde-treated rice bran could bind 7 g of dietary Ca post-ruminally, making it a potentially feasible tool to decrease intestinal Ca availability to aid in the prevention of milk fever.
    Effect of Nylon Bag and Protozoa on In Vitro Corn Starch Disappearance
    Zwieten, J.T. van; Vuuren, A.M. van; Dijkstra, J. - \ 2008
    Journal of Dairy Science 91 (2008)3. - ISSN 0022-0302 - p. 1133 - 1139.
    ruminal fermentation - dairy-cattle - rumen - degradation - digestion - maize - site - bacteria - extent - degradability
    An in vitro experiment was carried out to study whether the presence of protozoa in nylon bags can explain the underestimation of the in situ degradation of slowly degradable starch. Corn of a high (flint) and a low (dent) vitreousness variety was ground over a 3-mm screen, weighed in nylon bags with a pore size of 37 µ m, and washed in cold water. Samples of washed cornstarch were incubated in 40-mL tubes with faunated and defaunated ruminal fluid. An additional amount of washed corn, in nylon bags, was inserted in each incubation tube. Incubations were carried out for 0, 2, 4, 6, 12, and 24 h, and starch residue in tube and nylon bag was determined. In general, starch disappearance from the nylon bag was less than from the tube, and was less with faunated than defaunated rumen fluid, but corn variety did not affect starch disappearance. When no protozoa were present, the disappearance of starch from the bags was higher after 6 and 12 h incubation compared with presence of protozoa. However, in the tubes, there was no difference in starch disappearance due to presence or absence of protozoa. Estimated lag time was higher in presence (4.6 h) then absence (3.6 h) of protozoa. It was concluded that the effect of presence or absence of protozoa on starch disappearance differs within or outside nylon bags. The reduced disappearance rate of starch inside the nylon bags in the presence of protozoa helps to explain the underestimation of starch degradation based on the in sacco procedure when compared with in vivo data upon incubation of slowly degradable starch sources.
    Effects of washing procedure, particle size and dilution on the distribution between non-washable, insoluble washable and soluble washable fractions in concentrate ingredients
    Azarfar, A. ; Tamminga, S. ; Boer, H. - \ 2007
    Journal of the Science of Food and Agriculture 87 (2007)13. - ISSN 0022-5142 - p. 2390 - 2398.
    dairy-cows - protein - rumen - degradability - starch - energy - sacco - digestibility - degradation - feedstuffs
    The effects of washing procedure, particle size and dilution on the distribution of non-washable (NWF), insoluble washable (ISWF) and soluble washable (SWF) fractions were studied. The effects of three washing procedures (Yang (Y), Melin (M) and in situ (IS)) on the size of NWF, ISWF and SWF in six concentrate ingredients (maize, barley, milo, peas, lupins and faba beans), ground at two different particle sizes, were compared. Method M was further developed (method SM) by reducing the dilution ratio; its effect on NWF, ISWF and SWF was compared. A new washing method was developed (method AA) which involved continuous washing of nylon bags in a centrifuge beaker; its effect on NWF, ISWF and SWF at different dilutions with water was compared with the IS, M, SM and Y methods. The effects of different dilutions on SWF and soluble true protein (STP) in six concentrate ingredients were studied. The effects of grain, washing method and particle size on the size of NWF and ISWF were significant, with significant interactions between grain and particle size, grain and washing method, particle size and washing method, but no interaction between grain type, washing method and particle size. In method Y the size of NWF was smaller than in the other methods. The results showed that, except in lupins, NWF in grains was significantly higher than in legume seeds. Increasing the particle size significantly increased NWF, whereas ISWF was decreased. The size of SWF in legume seeds was higher than in the grains. Increasing the dilution, increased STP in legume seeds, but not in grains.
    Post-ruminal digestibility of crude protein from grass and grass silages in cows
    Cone, J.W. ; Gelder, A.H. van; Mathijssen-Kamman, A.A. ; Hindle, V.A. - \ 2006
    Animal Feed Science and Technology 128 (2006)1/2. - ISSN 0377-8401 - p. 42 - 52.
    neutral detergent fiber - degradation characteristics - dietary nitrogen - dairy-cows - rumen - bag - degradability - fermentation - invitro - feeds
    Grass samples were grown on a clay or sandy soil, fertilised with 150 or 300 kg N/ha per year, and harvested on different days during two consecutive growing seasons. The grass samples were stored frozen or ensiled after wilting to approximately 250 or 450 g DM/kg. The recoveries of crude protein (CP) after passing the rumen, the intestines and the total gastro-intestinal (GI) tract in grass and grass silages were determined with the two-step mobile nylon bag technique and a two-step in vitro technique, mimicking the rumen and intestine. Mobile nylon bag experiments were performed with 9 grass samples and 18 silages of the same grasses, pre-wilted to 250 or 450 g DM/kg. The in vitro experiments were performed with a series of 112 samples (54 grass and 58 grass silage samples). Both the in situ and in vitro results showed that the intestinal recoveries of CP were largely influenced by the amount of rumen-undegraded protein (RUP). A high value of RUP was compensated by an enhanced digestibility in the small and large intestine, resulting in a rather constant recovery of CP after passage through the total gastro-intestinal tract. It is suggested that residual CP after total tract passage is protein that is interwoven in the cell wall construction, cell wall bound or of microbial origin
    Physico-chemical characteristics and degradation rate of soluble protein obtained from the washout fraction of feeds
    Gierus, M. ; Jonge, L.H. de; Meijer, G.A.L. - \ 2005
    Livestock Production Science 97 (2005)2-3. - ISSN 0301-6226 - p. 219 - 229.
    ruminal degradation - dairy-cows - in-situ - grass-silage - rumen - degradability - hay - digestibility - supplements - system
    The (water)-soluble fraction of feeds is often assumed to be completely and immediately degraded in the rumen. The objective of this study was to separate the washout fraction (fraction A) obtained usually by difference after submitting the nylon bags to the machine-washing program, to investigate the nature and the degradation of the soluble crude protein in the washout fraction. The washout fraction obtained in vitro (filtrate) of 10 feeds was collected in water using nylon mesh as a filter. The feeds used in the study were: two grass silages, soybean meal, three corn gluten feeds, lupine meal, rapeseed meal, wet brewers grain silage and corn gluten feed silage. Average N losses during filtration and from machine-washed nylon bags ranged from 15% (rape seed meal) to 74% (grass silage) and were not different between procedures. N recovered in the filtrate ranged from 12% (soybean meal) to 60% (corn gluten feed silage) of sample N. The three fractions obtained from the filtrate were: soluble protein (TP), non-protein N (NPN) and fine particles (NS). The NS fraction was obtained after centrifugation of the filtrate and comprised 0% to 87% of N in the filtrate. Soluble protein (TP) in the supernatant was obtained after precipitation with trichloroacetic acid and N in the remaining supernatant was defined as non-protein N (NPN). Significant amounts of TP were found in soybean meal (58%), lupine meal (30%) and rapeseed meal (27%) as percent of total N in the filtrate. NPN ranged from 13% to 100% of N in the filtrate. The in vitro incubation of the protein N (NS + TP) showed that all fractions were not completely degraded, suggesting a potential participation as escape protein. Fine particles in the filtrate have similar degradation rates as the residue left in the filter. It is concluded that the washout fraction consisted of different crude protein fractions that were not always completely and immediately degraded in the rumen.
    Site and extent of starch degradation in the dairy cow - a comparison between in vivo, in situ and in vitro measurements.
    Hindle, V.A. ; Vuuren, A.M. van; Klop, A. ; Mathijssen-Kamman, A.A. ; Gelder, A.H. van; Cone, J.W. - \ 2005
    Journal of Animal Physiology and Animal Nutrition 89 (2005)3-6. - ISSN 0931-2439 - p. 158 - 165.
    rumen fluid - grass-silage - degradability - fermentation - digestion - prediction - incubation - enzymes
    Prediction of the supply of glycogenic precursors to dairy cows and the site of degradation of wheat, maize and potato starch (PS) were determined in an in vivo experiment and the results were compared with data obtained from experiments involving in situ nylon bag and in vitro gas production techniques. In a Latin square design experiment four lactating dairy cows fitted with a rumen cannula and T-piece cannulae in the duodenum and terminal ileum, received either a low-starch control diet or diets in which sugar beet pulp in the concentrate mixture had been replaced by wheat, maize or PS. Starch from the different sources was almost completely degraded in the total gastrointestinal tract. For all starches, the rumen was the main site of degradation in vivo. No digestion of PS in the small intestine was observed. In situ results suggested that 14% of wheat starch (WS), 47% of maize starch and 34% of PS escaped rumen fermentation. According to the gas production technique WS ferments quickest and potato slowest. PS had a low degradability during the first 8 (gas production) to 11 (in situ) h. However, according to both in vitro and in vivo measurements rumen degradability of PS was high. The results suggest that in situ and in vitro techniques should be performed in animals that have adapted to starch source to provide a more accurate simulation of the in vivo situation
    Inter-laboratory variation in in vitro gas production profiles of some selected feeds, using both manual and automated methods
    Rymer, C. ; Williams, B.A. ; Brooks, A.E. ; Davies, D.R. ; Givens, D.I. - \ 2005
    Animal Feed Science and Technology 123-124 (2005)1. - ISSN 0377-8401 - p. 225 - 241.
    temperature dried grass - neutral detergent fiber - fatty-acid production - fermentation kinetics - ruminant feeds - rumen fluid - pressure transducer - forages - degradability - degradation
    A study was conducted to estimate variation among laboratories and between manual and automated techniques of measuring pressure on the resulting gas production profiles (GPP). Eight feeds (molassed sugarbeet feed, grass silage, maize silage, soyabean hulls, maize gluten feed, whole crop wheat silage, wheat, glucose) were milled to pass a 1 mm screen and sent to three laboratories (ADAS Nutritional Sciences Research Unit, UK; Institute of Grassland and Environmental Research (IGER), UK; Wageningen University, The Netherlands). Each laboratory measured GPP over 144 h using standardised procedures with manual pressure transducers (MPT) and automated pressure systems (APS). The APS at ADAS used a pressure transducer and bottles in a shaking water bath, while the APS at Wageningen and IGER used a pressure sensor and bottles held in a stationary rack. Apparent dry matter degradability (ADDM) was estimated at the end of the incubation. GPP were fitted to a modified Michaelis¿Menten model assuming a single phase of gas production, and GPP were described in terms of the asymptotic volume of gas produced (A), the time to half A (B), the time of maximum gas production rate (tRM gas) and maximum gas production rate (RM gas). There were effects (P
    Alfalfa stem tissues: Impact of lignification and cell length on ruminal degradation of large particles
    Engels, F.M. ; Jung, H.G. - \ 2005
    Animal Feed Science and Technology 120 (2005)3-4. - ISSN 0377-8401 - p. 309 - 321.
    degradability - breakdown
    A series of experiments were conducted with alfalfa to determine how extensively rumen microorganisms can degrade various tissues within large stem pieces. The seventh internode from the base of the stem was collected from alfalfa clone 718 after 4 weeks of regrowth. Internode length and diameter were measured, and approximately 2 cm stem pieces were excised from the internodes. Stem pieces were incubated with rumen fluid in vitro for 24 h. Bee's wax was used to coat the stem pieces to prevent microbial access other than at one end of the stem pieces. After exposure to the rumen microorganisms, stem pieces were serially cross-sectioned starting at the exposed surface. Sections were examined by light microscopy to determine which tissues had been degraded and to what depth into the stem piece degradation had occurred. Non-lignified alfalfa stem tissues (chlorenchyma, collenchyma, cambium, and primary xylem parenchyma) were degraded to great depth (3700¿8200 ¿m) in stem pieces, but degradation of lignified tissues (phloem fibres and xylem fibres) was much more limited (150¿1360 ¿m). Depth of degradation was greater in stem pieces derived from long internodes compared to short internodes. Using longitudinal sections and isolated cells of stem tissues, it was found that mean cell length increased by approximately 50% with a doubling of internode length for all tissues examined. Many cell layers of non-lignified tissues were degraded whereas only the exposed cell layer of lignified tissues exposed at the cut end of the internode pieces was susceptible to degradation. Depth of degradation for non-lignified tissues was attributed to a combination of cell wall degradability, cell length, and the presence of intercellular spaces in chlorenchyma tissue. The lignified wall established a complete barrier to degradation of cells below those mechanically ruptured
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