563 research outputs found
Relationships between end products of fermentation using the gas production technique
No full textBook of abstract, 19th Congress of Animal Science and Production Associatio
In vitro rumen feed degradability assessed with DaisyII and batch culture: effect of sample size
No full textIn vitro degradability with DaisyII (D) equipment is commonly performed with 0.5g of feed sample into each filter bag. Literature reported that a reduction of the ratio of sample size to bag surface could facilitate the release of soluble or fine particulate. A reduction of sample size to 0.25 g could improve the correlation between the measurements provided by D and the conventional batch culture (BC). This hypothesis was screened by analysing the results of 2 trials. In trial 1, 7 feeds were incubated for 48h with rumen fluid (3 runs x 4 replications) both with D (0.5g/bag) and BC; the regressions between the mean values provided for the various feeds in each run by the 2 methods either for NDF (NDFd) and in vitro true DM (IVTDMD) degradability, had R2 of 0.75 and 0.92 and RSD of 10.9 and 4.8%, respectively. In trial 2, 4 feeds were incubated (2 runs x 8 replications) with D (0.25 g/bag) and BC; the corresponding regressions for NDFd and IVTDMD showed R2 of 0.94 and 0.98 and RSD of 3.0 and 1.3%, respectively. A sample size of 0.25 g improved the precision of the measurements obtained with D
Comparison among soybean seeds and rapeseed cake included in diets with two different protein levels using gas production technique
No full textA new approach to measure methane production from in vitro rumen fermentation of concentrates
No full textAnalysis of methane (CH4) produced from in vitrorumen fermentation is usually conducted on gas samples collected from headspace of bottles where gas is not vented. However, especially when concentrates are incubated, this procedure can lead to overestimation of CH4 values, as no venting causes partial solubilization of carbon dioxide (CO2) in fermentation fluid and an increased concentration of CH4 in headspace of bottles. This study aimed to measure gas (GP) and CH4 production using bottles where gas was vented into tight bags. Bottles (310 ml), filled with 60 ml of buffered rumen fluid (headspace=250 ml) and 0.040 g of feed sample, were not vented (NV) or vented (VE) at threshold pressure of 6.8 kPa by a valve connected to tight bag. Three concentrates, different for fermentative properties (corn meal, beet pulp, and flaxseed expeller), were incubated for 24 h at 39 °C. The experimental design was: 3 feeds × 3 replicates × 2 venting systems, plus 4 blanks, for a total of 22 bottles. A PC wireless-connected to bottles monitored GP, and GP was adjusted for solubilized CO2
. Gas samples (2 μl) were collected from headspace of bottles or from tight bags by a syringe and analyzed for CH4 by gas-chromatography. Data were analyzed by ANOVA considering feed, venting system and their interaction as sources of variation. Compared to NV, VE system provided greater (P<0.01) GP values, for all feeds. Adjustment of GP values removed differences between systems for beet pulp and flaxseed expeller, but not for corn meal. Measured CH4 concentrations were greater (P<0.01) for
NV compared to VE, for all feeds. When CH4 concentrations were adjusted for solubilized CO2, differences between two systems tended to decrease but did not disappear. Results evidence that gas venting plays a key role to achieve reliable measurements of in vitro CH4 production
Repeatability of in situ and in vitro digestibility measured at 24 or 48 h of incubation
No full textIn vitro rumen fermentation: Effect of head space pressure on the gas production kinetics of corn meal and meadow hay
No full textAn automated batch system, consisting in 20 bottles equipped with gas pressure sensors and venting valves, was used to test the effects of headspace pressure on the kinetics of gas production (GP). Two venting procedures were compared: with FT (fixed times) the gas accumulated in the headspace of bottles was released after 2, 4, 6, 8, 12, 24, 48, 72 and 144 h of incubation, whereas with FP (fixed pressure) the valves were opened at a threshold of 3.4 kPa. For each procedure, samples of corn meal and meadow hay (0.50 g) were incubated in 4 replications in 310 ml bottles with 25 ml of rumen fluid and 50 ml of medium for 144 h at 39 degrees C. Both with FT and FP, gas pressures at the times of venting, converted in terms of volumes, were adjusted or not for the amount of dissolved gas according to the Henry's law. Data were cumulated and they were best fitted by a first order model the which parameters are the asymptotic GP (A), the time at which half of A is produced (T1/2) and the sharpness (c) of the curve. The effects of the 2 procedures were evaluated using a Wilcoxon two-sample test. The headspace pressure obtained with FT peaked 18.0 +/- 2.84 kPa at 12 h on corn, while peaked 7.5 +/- 0.81 kPa at 48 h on hay. For corn, the un-adjusted GP achieved between 12 and 48 h of incubation were 21 and 8% lower with FT compared to FP (P=0.01), and FT also had greater standard deviations. A similar trend, less accentuated, was observed for hay. The T1/2 values were greater with FT compared to FP (+1.3 and +2.3 h, for corn and hay, respectively; P<0.05), suggesting that FT delayed the release of gas dissolved in the medium. After adjustment, the GP values provided by the 2 procedures continued to be different for corn: compared to FP, FT reduced GP at 12,24 and 48 h (P=0.01). Adjustments removed all the differences for hay due to the venting procedure. Using the FT procedure, headspace volume, venting frequency and amount of fermentable matter must be carefully balanced to avoid high headspace pressures, lowered gas release and, hence, altered GP kinetics. (C) 2010 Elsevier By. All rights reserved
Influence of main dietary chemical constituents on the in vitro gas and methane production in diets for dairy cows
No full textSynthetic and natural polyphenols with antioxidant properties stimulate rumen microbial growth in vitro
No full textThis trial compared the effects of two antioxidant phenols, butyl-hydroxyl-toluene (BHT) and a blend of polyphenols extracted from red chicory, on in vitro degradability, gas production (GP), volatile fatty acids, and microbial nitrogen production, using meadow hay and corn grain as fermentation substrates. A batch culture system with automated gas pressure detectors was used. Four replicates of each feed were incubated for 72 h without additive (Control, CTL) or with the addition of low (0.15 mg/g feed) or high (1.5 mg/g feed) dosages of BHT or red chicory. GP curves were fitted to estimate the time at which half of total GP (t1/2) was achieved. The t1/2 values for meadow hay and corn grain were ~16 and 9 h, respectively. A second incubation, conducted using the same experimental design, was stopped at t1/2. Compared with CTL, degradability and GP kinetics were not affected by the two dosages of BHT, except for GP, which increased after 48 h of incubation (P < 0.01). In the second incubation, BHT increased acetate at the expense of butyrate proportion (P < 0.01). Red chicory extract did not influence GP, feed degradability, or volatile fatty acids production in either incubation. Both BHT and red chicory induced a dosage-dependent increase in microbial nitrogen production at t1/2 (P < 0.05), on average from 7.0 to 13.9 mg/g DM. Collectively, our data suggest that increasing dosages of the two additives with antioxidant properties could have induced a shift in the partition of energy, with a higher proportion of nutrients channelled towards microbial protein synthesis
In vitro degradability and energy value of rapeseed cake produced on farm by cold extraction press
No full textMirko Breyer, Publisher from Križevci
No full textU tekstu se donosi kratak prikaz života i djela križevačkog nakladnika Mirka Breyera. Mirko Breyer bio je pr\>ak hrvatske bibliografije, bibliofil, knjižar-nakladnik i antikvar. Obilježio je početak dvadesetog stoljeća svojim kulturnim radom. Autor donosi dio objavljene i dio neobjavljene građe o Mirku Breyeru.The text is a short overview of the life and work of a Križevci publisher Mirko Breyer. Mirko Breyer was a pioneer of Croation bibliography, a bibliophile, bookseller, publisher and antiquarian. He marked the beginning of the 20th century with his cultural work. The author presents parts of published as well as unpublished material on Mirko Breyer, with his bibliography
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