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Journal ArticleDOI

Methane production by mixed ruminal cultures incubated in dual-flow fermentors.

01 Jan 2004-Journal of Dairy Science (Elsevier)-Vol. 87, Iss: 1, pp 112-121

TL;DR: Dilution rate and forage-to-concentrate ratio altered the partition of substrate by microbes and underestimated methane output at higher dilution rates and with high forage diets.

AbstractThis study evaluated the effects of dilution rate and forage-to-concentrate ratio on gas production by rumen microbes. Continuous cultures were used to monitor methane production at three liquid dilution rates (3.2, 6.3, or 12.5%/h) and three forage-to-concentrate ratios (70:30, 50:50, or 30:70). Filtered ruminal contents were allowed 6 d of adaptation to diets followed by 7 d of data collection. Forage consisted of pelleted alfalfa and the concentrate mix included ground corn, soybean meal, and a mineral and vitamin premix. The experiment was replicated in a split-plot design. Total volatile fatty acid production averaged 58.0 mmol/d and was not affected by treatment. Molar proportion of acetate increased with increasing forage-to-concentrate ratio. Molar proportion of propionate tended to decrease at dilution rate of 12.5%/h and increased with the medium and low forage-to-concentrate ratio. Culture pH tended to be greater at a dilution rate of 12.5%/h. Methane production that was calculated from stoichiometric equations was not affected by treatments. However, methane production based on methane concentration in fermentor headspace resulted in an interaction effect of treatments. Stoichiometric equations underestimated methane output at higher dilution rates and with high forage diets. Total diet fermentability was lowest at dilution rate of 3.2%/h. Increasing dilution rates increased microbial yield; increasing the proportion of concentrate improved microbial efficiency. Dilution rate and forage-to-concentrate ratio altered the partition of substrate by microbes. Methane production based on actual concentrations differed from values estimated using stoichiometry of end-product appearance.

Topics: Dilution (55%)

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Citations
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Journal ArticleDOI
TL;DR: The different methods used to inhibit the H2-consuming bacteria are analyzed, such as biokinetic control, heat-shock treatment and chemical inhibitors along with their advantages/disadvantages for their application on an industrial scale.
Abstract: In this work, H2 production by anaerobic mixed cultures was reviewed. First, the different anaerobic microbial communities that have a direct relation with the generation or consumption of H2 are discussed. Then, the different methods used to inhibit the H2-consuming bacteria are analyzed (mainly in the methanogenesis phase) such as biokinetic control (low pH and short hydraulic retention time), heat-shock treatment and chemical inhibitors along with their advantages/disadvantages for their application on an industrial scale. After that, biochemical pathways of carbohydrate degradation to H2, organic acids and solvents are showed. Fourth, structure, diversity and dynamics of H2-producers communities are detailed. Later, the hydrogenase structure and activity is related with H2 production. Also, the causes for H2 production inhibition are analyzed along with strategies to avoid it. Finally, immobilized-cells systems are presented as a way to enhance H2 production.

315 citations


Journal ArticleDOI
Abstract: Batch cultures of mixed rumen micro-organisms were used to study the effects of three fibrolytic enzymes (xylanase from Trichoderma viride (XYL) and fibrolytic enzymes from Aspergillus niger (ASP) and Trichoderma longibrachiatum (TR)) on the fermentation of three substrates composed of grass hay:concentrate in the proportions (dry matter (DM) basis) of 0.7:0.3 (HF), 0.5:0.5 (MF) and 0.3:0.7 (LF). Enzymes were characterized for xylanase, endoglucanase, exoglucanase and amylase activities, and were supplied at rates of 40 and 80 enzymatic units/g substrate DM. In 8 h incubations, all enzymes increased (P=0.048 to P 0.05). A decrease (P 0.05) was detected on OMAF and methane:OMAF ratio. In general, few differences were detected between both doses of enzymes, which indicate than the used enzymes would be effective in enhancing ruminal degradation of substrates at a dose lower than 80 enzymatic units/g substrate DM.

90 citations


Journal ArticleDOI
Abstract: An in vitro gas production technique was used to measure total gas and methane (CH4) production from commercial total mixed rations (TMR) for lactating dairy cows. The TMR were collected from six commercial dairy farms in the San Joaquin Valley of California (USA), and the campus dairy at the University of California in Davis, for evaluation using an in vitro gas production technique to determine the CH4 concentration of total gas. The TMR samples were analyzed for nutritional components and in vitro assays were conducted to measure neutral detergent fibre digestibility, and total gas and CH4 production. The TMR were similar in nutrient composition, with CP ranging from 163 to 185 g/kg DM. There were differences among TMR in total gas production at 6, 24, 30, 48 and 72 h of in vitro incubation, and the TMR differed (P

70 citations


Journal ArticleDOI
Abstract: Empirical equations were developed to accurately predict passage rate ( K p ) in ration formulation models for all classes of dairy and beef cattle. The database was comprised of studies that used external markers, and 553, 195 and 766 treatment means were used to develop the K p equations for forages, concentrates and liquid, respectively. A random coefficients model that used each study effect as a random variable was used to select statistically significant input variables to predict rate of passage. The parameters of the variables were estimated using ordinary least square method. The equations developed were: K p forage = (2.365 + 0.0214FpBW + 0.0734CpBW + 0.069FDMI)/100; K p concentrate = (1.169 + 0.1375FpBW + 0.1721CpBW)/100 and K p liquid = (4.524 + 0.0223FpBW + 0.2046CpBW + 0.344FDMI)/100, where K p is the passage rate, h −1 ; FpBW the forage DMI as a proportion of BW, g/kg; CpBW the concentrate DMI as a proportion of BW and FDMI is the forage DMI, kg. These K p equations for forages, concentrates and liquid explained 87%, 95% and 94%, respectively of the variation in passage rates in the database used in equation development after adjustment for random study effect. These and other published equations were evaluated with an independent database. In this evaluation, the R 2 of the new equations were 0.39, 0.40 and 0.25 for prediction of the passage of forages, concentrates and liquid, respectively, which was higher than the R 2 of the previously published equations by 0.03–0.19, 0.01–0.14, and 0.04–0.16 for forages, concentrates and liquid, respectively. The root mean square prediction error (RMSPE) was reduced by 3–22%, 2–33%, and 4–31% in the prediction of K p of forages, concentrates and liquid, respectively, with the new equations. These new empirical equations are suitable for predicting passage rate in cattle, but predictability overall is still low and increases in the accuracy of predicting passage rates requires development of a mechanistic model that accounts for more biologically important variables affecting passage rate ( e.g. physical property of particles, water intake and flux, and within day variation in intake).

66 citations


Additional excerpts

  • ..., 2004) and microbial growth (Eun et al., 2004; Owens and Goetsch, 1986)....

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Journal ArticleDOI
TL;DR: The results indicate that MRT(solute)GIT and the degree of digesta washing are related to digestion type, whereas variation in MRT('fluid passage')GIT is influenced mainly by effects of body mass and food intake, and fluid throughput and digestiona washing emerge as important correlates of digestive anatomy.
Abstract: The relevance of the mean retention time (MRT) of particles through the gastrointestinal tract (GIT) is well understood and MRTparticleGIT is an important parameter in digestion models. Solute markers have been used to estimate MRTsoluteGIT (or ‘fluid passage’) in animals, but the relevance of this measure is less evident and is usually sought in its relation to MRTparticleGIT. The ratio between the two measures indicates the degree of ‘digesta washing’, with little washing occurring at ratios of 1, aborad washing at ratios N1 (where the solute marker travels faster than the particle marker), and orad (retrograde) washing at ratios b1 (where the solute marker travels slower than the particle marker). We analysed digesta washing in a dataset of 98 mammalian species including man of different digestion types (caecum, colon and nonruminant foregut fermenters, and ruminants), controlling for phylogeny; a subset of 72 species allowed testing for the influence of food intake level. The results indicate that MRTsoluteGIT and the degree of digesta washing are related to digestion type, whereas variation in MRTparticleGIT is influenced mainly by effects of body mass and food intake. Thus, fluid throughput and digesta washing emerge as important correlates of digestive anatomy. Most importantly, primates appear constrained to little digesta washing compared to non-primate mammalian herbivores, regardless of their digestion type. These results may help explain the absence of primates from certain herbivore niches and represent a drastic example of a physiologic limitation in a phylogenetic group. Moreexperimental research is required to illuminate relative benefits and costs of digesta washing.

56 citations


Cites background from "Methane production by mixed ruminal..."

  • ...A large number of old and recent in vitro studies with ruminant inoculum 339 (Isaacson et al. 1975; Shi and Weimer 1992; Meng et al. 1999; Eun et al. 2004; Fondevila and 340 Pérez-Espés 2008) and limited in vivo evidence in domestic cattle (Wiedmeier et al. 1987a; 341 Wiedmeier et al. 1987b;…...

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  • ...(Isaacson et al. 1975; Shi and Weimer 1992; Meng et al. 1999; Eun et al. 2004; Fondevila and 340 Pérez-Espés 2008) and limited in vivo evidence in domestic cattle (Wiedmeier et al....

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References
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01 Jan 1960

23,007 citations


Journal ArticleDOI

21,053 citations


Book
12 Aug 1994

8,817 citations


"Methane production by mixed ruminal..." refers background or methods in this paper

  • ...The amount of substrate fermented to VFA, CH4, and CO2 was calculated based on the moles of individual VFA produced, daily methane output, and CO2 released from fermentation and buffer addition (Wolin, 1960; Van Soest, 1994; Blümmel et al., Journal of Dairy Science Vol. 87, No. 1, 2004 1997)....

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  • ...Increased lysis of microbial cells as a consequence of substrate exhaustion and uncoupled fermentation may contribute to reduced net growth at longer incubation times (Van Nevel and Demeyer, 1977)....

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  • ...Also, total gas yield can vary considerably due to the incorporation of carbons into microbial mass as well as the different metabolic pathways by which carbohydrate fractions can be degraded by rumen microbes (Krishnamoorthy et al., 1991; Beuvink and Spoelstra, 1992; Van Soest, 1994)....

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  • ...It is known that the growth yields of ruminal microbes can be relatively high, and that microbial cells have a negative oxidation-reduction state (Van Kessel and Russell, 1996)....

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  • ...Stoichiometric equations relating substrate degradation to VFA and gas production have been developed and are commonly used to estimate digestibility of ruminant feeds (Wolin, 1960; Russell and Baldwin, 1979; Menke et al., 1979; Van Soest, 1994)....

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Journal ArticleDOI
Abstract: Linear regression equations have been obtained to directly calculatenutrient requirements of dairy cattle (TDN, DE, ME, NEL,CP, Ca, P, Vitamin A and Vitamin D) on differentphysiological stages: maintenance, pregnancy and milkproduction based on NRC nutrient requirements tables. TheR-square was calculated for each equation to establish thedegree of adjustment.

6,661 citations


Journal ArticleDOI
TL;DR: This article corrects the article on p. 100 in vol.
Abstract: [This corrects the article on p. 100 in vol. 41.].

3,202 citations


"Methane production by mixed ruminal..." refers background in this paper

  • ...The dilution rates tested in the present study were similar to those used by Isaacson et al. (1975) and, therefore, the yield of microbial biomass per mol ATP (YATP) was set to be 7.5, 11.6, and 16.7 mg/mmol ATP for dilution rates of 3.2, 6.3, and 12.5%/h, respectively....

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  • ...Hydrogen and CO2 are the major precursors of CH4 formation in the rumen (Hungate, 1967), and most methanogens can utilize these substrates to generate ATP (Thauer et al., 1977)....

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  • ...Consequently, microbial biomass from glucose consumption was calculated as: Microbial biomass (g/d) = 0.8 YATP (2 Acetate, mmol/d + 3 Propionate, mmol/d + 3 Butyrate, mmol/d + CH4, mmol/d)/1,000 Energy contents of acetate, propionate, butyrate, valerate, isobutyrate, and isovalerate were used to estimate digestible energy....

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  • ...The direct source of CO2 is the fermentation of glucose by various pathways yielding VFA, ATP, and CO2....

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  • ...However, changing dilution rates did affect the efficiency of microbial protein synthesis that was reported to be 7.5, 11.6, and 16.7 g of cells/mol of ATP at fractional dilution rates of 2, 6, and 12%/h, respectively (Isaacson et al., 1975)....

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