Relationship between in vitro gas production and neutral detergent fibre disappearance in three tropical grasses

1996 ◽  
Vol 1996 ◽  
pp. 219-219
Author(s):  
M. Herrero ◽  
N.S. Jessop

In vitro gas production techniques have been used to nutritionally characterise feedstuffs for ruminants. Consideration of both the soluble and insoluble fractions has recently been shown to be essential for adequate description of cell wall disappearance (Jessop and Herrero, 1996). This study investigates how gas production measurements can be used to predict neutral detergent fibre (NDF) disappearance by correcting for the gas volume produced in the early stages of fermentation from neutral detergent solubles (NDS). The study was carried out using three tropical grasses.

1996 ◽  
Vol 1996 ◽  
pp. 219-219
Author(s):  
M. Herrero ◽  
N.S. Jessop

In vitrogas production techniques have been used to nutritionally characterise feedstuffs for ruminants. Consideration of both the soluble and insoluble fractions has recently been shown to be essential for adequate description of cell wall disappearance (Jessop and Herrero, 1996). This study investigates how gas production measurements can be used to predict neutral detergent fibre (NDF) disappearance by correcting for the gas volume produced in the early stages of fermentation from neutral detergent solubles (NDS). The study was carried out using three tropical grasses.


1998 ◽  
Vol 22 ◽  
pp. 207-208
Author(s):  
R. S. Lowman ◽  
N. S. Jessop ◽  
M. K. Theodorou ◽  
M. Herrero ◽  
D. Cuddeford

Following the development of the Menke technique in 1979, the measurement of gas production in vitro has become increasingly popular for investigating the kinetics of rumen fermentation. The aim of this study was to compare the gas production profiles for three foods using two in vitro gas production techniques; the Menke et al. (1979) technique (MT) and the pressure transducer technique (PTT) (Theodorou et al., 1994). Both techniques involve recording gas production throughout the incubation of a food sample with rumen fluid. The MT incubations are made in gas-tight syringes where the volume of gas produced causes the plunger to move up the syringe barrel. The PTT involves measuring gas production in fermentation bottles using a pressure transducer and syringe assembly to measure the pressure and corresponding gas volume. As the medium to rumen fluid ratios also differ between techniques; 2:1 in the Menke technique and 9:1 in the PTT, both ratios were investigated in this study.


2005 ◽  
Vol 123-124 ◽  
pp. 107-118 ◽  
Author(s):  
Gonzalo Hervás ◽  
Pilar Frutos ◽  
F. Javier Giráldez ◽  
Manuel J. Mora ◽  
Begoña Fernández ◽  
...  

1997 ◽  
Vol 64 (1) ◽  
pp. 71-75 ◽  
Author(s):  
M. Blümmel ◽  
P. Bullerdieck

AbstractThe need to complement in vitro gas production measurements with residue determination is demonstrated by the recalculation and reassessment of published data on in vitro gas production, in sacco degradabilities and voluntary dry matter intake (DMI). The in sacco degradability — gas volume ratio was determined at 24 and 48 h of incubation, termed partitioning factor (PF) and combined with rate and extent parameters of in sacco degradability and in vitro gas production to predict DMI. In vitro gas production and in sacco degradability characteristics (a + b) and c as described by the equation y = a + b(1−ect) explained 0·373 and 0·668 respectively of the variation in DMI of 19 legume and grass hays. The complementation of gas production parameters by the PF24 increased the R2 value to 0·744 with PF24 accounting for 0·407 of the variation in DMI, the rate of gas production (c) for 0·218 and the extent of gas production (a + b) for 0·119 of the variation in DMI. As a single parameter, PF48 showed the highest correlation (R2 = 0·597) with DMI but the combination of PF4S with rate and extent of in sacco or in vitro gas production measurements did not improve the correlation further, probably due to an intercorrelation between rates of fermentation and PF4S. Hays which were degraded at faster rates had higher PF values indicating proportionally higher microbial yield and lower short-chain fatty acid production per unit substrate degraded. Generally, hays with high in sacco degradabilities but proportionally low gas production i.e. hays with high PF values showed higher DMI.


1998 ◽  
Vol 1998 ◽  
pp. 69-69
Author(s):  
S. Fakhri ◽  
A. R. Moss ◽  
D.I. Givens ◽  
E. Owen

The gas production (GP) technique has previously been used to estimate the gas volume (fermentable energy (FE)) of compound feed ingredients for ruminants (Newbold et al., 1996). It was shown that the FE content of feed mixtures was represented by the combination of the total gas from the incubation of the individual feeds. However this additivity might not be consistent throughout the incubation period. The objectives were to test whether 1. other GP parameters give better estimates of FE for simple mixtures and are they additive; 2. whether organic matter apparently degraded in the rumen (OMADR) explain differences in GP; and 3. to find out if there are any other better measures than OMADR for estimating FE.


1997 ◽  
Vol 1997 ◽  
pp. 196-196
Author(s):  
S. Fakhri ◽  
A. R. Moss ◽  
D.I. Givens ◽  
E. Owen

Recently, the automatic in vitro gas production techniques (e.g. Cone. 1994; Theodorou et al., 1994) have been developed to study rumen fermentation kinetics. Many approaches have been taken. This work investigates the suitability of different methods for estimating the rumen fermentation of two starch rich feedstuffs.


2004 ◽  
Vol 84 (1) ◽  
pp. 105-111 ◽  
Author(s):  
M. Blümmel ◽  
E. E. Grings ◽  
M. R. Haferkamp

The effects of suppression of annual bromes (Bromus japonicus Thunb. and Bromus tectorum L.) by atrazine application on the nutritive quality of extrusa diet samples (EDS) collected from the esophagus were investigated, and EDS quality estimates were compared with weight gain of grazing steers. Analysis on EDS included crude protein (CP), in vitro organic matter degradability (IVOMD), and gas production profiles in N supplemented and unsupplemented incubation media. Brome-suppression tended (P = 0.07) to increase CP content but effects on gas production kinetics and IVOMD were dependent on incubation medium N-level. In N-unsupplemented incubations, asymptotic gas production was less and rates of gas production were greater in EDS from brome-suppressed compared to undisturbed pasture. No such differences were found for N-supplemented incubations. Weight gains of steers grazing brome-suppressed pastures were 16% greater (P = 0.007) than from control pastures. The R2 for the comparison of predicted and measured gains were 0.90 (P < 0.0001), 0.96 (P < 0.0001), and 0.90 (P < 0.0001) using CP, IVOMD (N-low), and IVOMD (N-rich) as the predicting variable, respectively. Best predictions using in vitro gas production measurements were obtained from 24 h gas volume recording (R2 = 0.93, P < 0.0001). Best-fit model (sigmoidal vs. exponential) depended on grazing period and N-level, and the sigmoidal Gompertz model best described most gas production profiles. Key words: Forage quality, gas production, weight gain, beef steers


1997 ◽  
Vol 77 (5) ◽  
pp. 757-768 ◽  
Author(s):  
M. Blümmel ◽  
K. Becker

Fifty-four roughages of known voluntary dry-matter intakes (DMI; range 7·8−35·2 g/kg live weight per d) were examined in vitro in a gas production test. Samples (200 mg) of roughage and roughage neutral-detergent fibre (NDF) respectively were incubated in a mixed suspension of rumen contents for 96 h and the gas volumes recorded after 4,6,8,12,24,30,36,48,54,60 and 96 h. The kinetics of gas production were derived from the volume recordings described by the exponential equation Y=A+B(l—e-ct) where A is the intercept and ideally reflects the fermentation of the soluble and readily available fraction of the feed, B describes the fermentation of the insoluble (but with time fermentable) fraction and c the fractional rate at which B is fermented per h; A+B describes total fermentation. In vitro true dry matter (TD) and NDF degradabilities (NDF-D) after 24 h incubation were also determined. Of the variation in DMI, 75% was accounted for by the in vitro gas production parameters A, B and c in stepwise multiple regressions; 82% of the variation in DMI was explained by the parameters (ANDF+BNDF) and cNDF as obtained from the incubation of roughage NDF. The rate constants (c) were less important than parameters related to the extent of gas production, accounting for only 6·5 (whole roughage) and 4·1% (NDF) of the variation in DMI. There was no statistical advantage in the use of the exponential model describing extent and rate of fermentation over some of the simple gas volume measurements: 75% of the variation in DMI was accounted for by in vitro gas production of whole roughage after 8 h of incubation. On average gas production from NDF measured from 24–96 h accounted for 81% of the variation in DMI. A combination of gas volume measurements after a short period of incubation (4–8 h) with a concomitant determination of NDF-D after many hours (≥24 h) can render NDF preparations and long incubation times redundant. A method is suggested to obtain two results for DMI prediction in one single incubation. Of the variation in DMI 80% was accounted for by the incubation of 500 mg whole roughage when incubation was terminated after 24 h and the residual undegraded substrate quantified.


1998 ◽  
Vol 22 ◽  
pp. 247-248
Author(s):  
S. López ◽  
M. D. Carro ◽  
C. Valdés ◽  
J. S. González ◽  
F. J. Ovejero

Quantitative expressions of the kinetics of digestion are needed to estimate more precisely the quantity and composition of nutrients digested from feeds and their subsequent efficiency of utilization by the animal (Mertens, 1993). Degradation kinetic parameters are estimated by fitting appropriate models to data resulting from the measurement of either the undigested residue or the fermentation end-products after exposure of the feed to digestion. Kinetic data can be collected using either in vitro or in situ procedures. The in situ porous synthetic fibre bag technique has been extensively used to describe the kinetics of feeds degradation in the rumen. Several in vitro gas production methods have been developed to assess fermentation kinetics. The aim of this work was to study the relationship between rumen degradation parameters of forages determined either by the in situ procedure or by the gas production technique and to evaluate the potential of gas production measurements to assess the extent of dry matter degradation in the rumen.


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