Relationship between in vitro solubility and rumen degradability of forage nitrogen

1998 ◽  
Vol 22 ◽  
pp. 344-345
Author(s):  
D. M. Komwihangilo ◽  
E. R. Deaville ◽  
D. I. Givens ◽  
E. Owen
Keyword(s):  
Rumen Fluid ◽  
Exponential Model ◽  
Internal Diameter ◽  
Fresh Sample ◽  
Total N ◽  
Freeze Dried ◽  
Outflow Rate ◽  
Kjeldahl Method

It is widely accepted that robust and accurate in vitro techniques are required to predict the proportion of food nitrogen (N) degraded in the rumen. One such technique is to estimate the solubility of food N. In these experiments, relationships between solvent soluble N and in situ rumen degradability of forage N were investigated.Samples of 11 fresh grasses (FG) (mainly perennial ryegrass) and their corresponding silages (GS) were used. GS was prepared from material ensiled in laboratory scale silos for 90 days. Prior to the experiments, FG and GS samples were initially hand chopped to approximately 1 cm lengths. In the in situ study a fresh sample equivalent to 0-5 g DM was weighed into polyester bags (pore size 43 μ 200 X 90 mm internal diameter). Duplicate bags for each of FG or GS were incubated in the rumen of three wethers for 0, 3, 8, 16, 24, 45 and 72 h. The incubated residues including the 0 h samples were washed in a washing machine and freeze-dried for 48 h. Rumen degradability characteristics and effective degradability (ED, at rumen outflow rate of 0.08 per h) of N were calculated using the exponential model of Ørskov and McDonald (1979). In vitro solubility of N (S) was determined by incubating for 1 h (at room temperature) the fresh sample (0.5 g on dry matter basis) in each of the four solvents: Borate phosphate buffer (BFB), Durand's buffer (DB), clarified rumen fluid (CRF) and distilled water within a balanced three way factorial design (three operators; four solvents; 11 forages; Deaville et al., 1997). Residues from S were filtered under vacuum and the filter paper plus residue were oven dried for 18 h at 100°C. All samples and residues were analysed for total N using Kjeldahl method (Ministry of Agriculture, Fisheries and Food, 1986). Factorial analysis on the general linear model (Minitab®, 1994) was used in the analysis of variance(ANOVA) for in vitro data and regression analyses of in situ and in vitro data were performed (Minitab®, 1994). Only the regression results are reported here.

scholarly journals Evaluation of a mathematical model of rumen digestion and an in vitro simulation of rumen proteolysis to estimate the rumen-undegraded nitrogen content of feedstuffs

1983 ◽  
Vol 50 (3) ◽  
pp. 555-568 ◽  
Author(s):  
U. Krishnamoorthy ◽  
C. J. Sniffen ◽  
M. D. Stern ◽  
P. J. Van Soest
Keyword(s):  
Mathematical Model ◽  
Rumen Fluid ◽  
Full Range ◽  
Enzyme Concentration ◽  
Total N ◽  
Protease Enzyme ◽  
Residual N

1. Twelve grain mixtures, one lucerne (Medicago sativa) hay and one maize silage which had been used in mixed diets for which dietary nitrogen undegraded in the rumen (UDN) had been estimated with duodenally-cannulated cows, were studied. Total N in the feeds was fractionated into pool A (N soluble in borate–phosphate buffer), pool B (total N–(pool A + pool C)) and pool C (acid-detergent-insoluble N or residual N after 24 h incubation in protease solution).2. N solubilization in protease solution containing 6·6 units/ml (substrate-saturating enzyme concentration) indicated the presence of subfractions in pool B, with different rates of solubilization. Such subfractions were not detectable from in situ, Dacron bag, estimates of N solubilization.3. UDN was estimated using a dynamic mathematical model and rate-constants obtained from N solubilization in protease solution or in situ.For three grain mixtures tested using the protease technique the model predicted UDN values of 7, 10 and 12% compared with values of 47, 66 and 59% estimated in vivo. The full range of experimental feeds was tested using the in situtechnique and UDN values predicted by the model were used to derive UDN values for twelve mixed diets. The latter values were significantly but not closely correlated with those determined in vivo (r2 0·41, P < 0·05).4. An attempt was made to simulate rumen proteolysis in vitro by choosing a protease enzyme concentration (0·066 units/ml) providing a proteolytic activity similar to that of whole rumen fluid. The experimental samples of feed were subjected to simulated rumen proteolysis for 18 or 48 h to resemble the mean retention times in the rumen for grain mixtures and roughages respectively. The residual N at the end of incubation was considered as an estimate of UDN. The UDN values estimated from simulated rumen proteolysis and those determined in vivo for twelve mixed diets were in close agreement (r2 0·61, P < 0·01).5. Simulated rumen proteolysis can serve as a simple, rapid and sensitive method to estimate UDN in a variety of feedstuffs.

Repeatability of in vitro digestibility assays of forages when using fresh, frozen or freeze-dried cow faeces instead of sheep rumen liquor as sources of micro-organisms

1995 ◽  
Vol 1995 ◽  
pp. 110-110 ◽  
Author(s):  
S Akhter ◽  
E Owen ◽  
M K Theodorou ◽  
S L Tembo ◽  
E R Deaville
Keyword(s):  
Freeze Drying ◽  
Rumen Fluid ◽  
In Vitro Digestibility ◽  
Two Stage ◽  
Freeze Dried ◽  
Fresh Frozen ◽  
Sheep Rumen ◽  
Micro Organisms

Previous studies (El Shaer, Omed and Axford, 1987; Akhter, Owen, Fall, O'Donovan and Theodorou, 1994) with the two-stage in vitro procedure of Tilley and Terry (1963) have shown a high correlation between digestibilities of forages as determined using either sheep rumen liquor, sheep faeces or cow faeces as the microbial inoculum. In the first study of the of the present investigation one objective was to examine the repeatability of these digestibility measurements when made on different occasions. A second objective was to assess whether the correlations between faecal and rumen fluid based inocula could be improved if microorganisms were obtained from pairs rather than individual animals. The objective in the second study using forages of known in vivo digestibility, was to investigate the effect of freezing or freeze-drying of faeces on the repeatability of digestibilities of forages determined in vitro using micro-organisms from cow faeces.

scholarly journals A comparative study of ruminal activity in Churra and Merino sheep offered alfalfa hay

1997 ◽  
Vol 65 (1) ◽  
pp. 121-128 ◽  
Author(s):  
M. J. Ranilla ◽  
M. D. Carro ◽  
C. Valdés ◽  
F. J. Giráldez ◽  
S. López
Keyword(s):  
Cell Wall ◽  
Rumen Fluid ◽  
Merino Sheep ◽  
Rumen Ph ◽  
Sheep Rumen ◽  
Fermentation Parameters ◽  
Micro Organisms ◽  
Kinetics Of

AbstractA study was carried out to compare the fermentation parameters and kinetics of digestion of a range of different foods in the rumen of two breeds of sheep (Churra and Merino). Ten mature sheep (five Churra and five Merino), each fitted with a rumen cannula, were used in this study. In situ rumen degradability of both dry matter (DM) and cell wall was greater in Churra than in Merino sheep, the breed differences being significant for most of the foods used in the study (P < 0·05). These differences were greater when the foods had a higher cell wall concentration and this could be related to differences in the ruminal environment. However, when the foods were incubated with rumen fluid their in vitro organic matter (OM) degradability was similar in both breeds. Rumen pH was higher (P < 0·05) and ammonia concentrations were lower (P < 0·05) in Churra than in Merino sheep. Rumen volatile fatty acid concentrations tended to be higher in Merino than in Churra sheep, though differences were only significant just before feeding (P < 0·05). The ratio acetate: propionate was higher in the Churra than Merino breed before and 12 h after feeding (P < 0·05). Protozoa numbers in rumen liquid were similar for both genotypes. The greater degradation of forages in the rumen of Churra sheep is discussed in relation to the possible higher activity of fibre-degrading micro-organisms and the greater buffering capacity of the rumen contents against fermentation acids, which could result in more favourable conditions for the microbial degradation of foods in the rumen.

Influence of drying method and ageing on chemical and physical properties andin vitrodegradation characteristics of grass and maize samples

1996 ◽  
Vol 126 (1) ◽  
pp. 7-14 ◽  
Author(s):  
J. W. Cone ◽  
A. H. Van Gelder ◽  
H. J. P. Marvin
Keyword(s):  
Physical Properties ◽  
Rumen Fluid ◽  
Sugar Content ◽  
Soluble Sugars ◽  
Drying Methods ◽  
Drying Method ◽  
Crude Fibre ◽  
Fermentation Kinetics ◽  
Freeze Dried

SUMMARYThe influence of different drying conditions on the chemical composition, physical properties,in vitroorganic matter degradability and fermentation kinetics of forages was investigated using young and old grass (Lolium perenne) samples (harvested on 15 June and 9 July 1992 at Lelystad, The Netherlands) and young and old maize (Zea mayscv. Scana) stem samples (harvested on 19 August and 30 September 1991 at Lelystad). The samples were either freeze-dried with a maximum sample temperature of 10 °C, dried in a vacuum at 20 °C or air-dried at 30, 50, 70 and 105 °C. The different drying methods had little effect on ash, acid detergent fibre (ADF), acid detergent lignin (ADL), crude fibre and crude protein (CP) contents andin vitrodegradation of the forage samples. However, some effects were found for sugars and phenolic acids. The neutral detergent fibre (NDF) content in protein-rich samples and the fermentation kinetics in rumen fluid differed significantly according to drying method. In samples dried other than by freeze-drying, proteins were bound to the NDF content and in some cases an effect on the amount of soluble sugars was also seen. Physical properties of the samples were determined by differential scanning calorimetry (DSC) and differences were found between freeze-dried materials and those dried at 70 °C. The influence of age on the maize samples was very pronounced, whereas it had little effect on the characteristics of the grass samples, with the exception of a decreased CP content and an increased sugar content after acid hydrolysis.

Medial morphometry and mechanics of sequential rabbit ear arteries and myograph ring segments

1983 ◽  
Vol 245 (5) ◽  
pp. H840-H848
Author(s):  
J. G. Walmsley ◽  
M. P. Owen ◽  
J. A. Bevan
Keyword(s):  
Side Branch ◽  
Internal Diameter ◽  
Terminal Branch ◽  
Average Value ◽  
Ear Artery ◽  
Rabbit Ear ◽  
Valid Comparison ◽  
The Media

The medial structure of three different branching orders of arteries in the rabbit ear was studied to assess the possible significance with regard to mechanical behavior determined with the in vitro myograph. The central ear artery, its main side branch, and a terminal branch were fixed while dilated in situ at 100 mmHg; this resulted in internal diameters of 960, 456, and 251 micron, respectively. The average ratio of medial thickness to internal diameter was 0.0293 for arteries in situ and 0.0487 for arterial rings in vitro. Measurements undertaken for the determination of smooth muscle (SM) stress included the percentage of SM in the media (74%) and the pitch of SM (0.89 degrees). These parameters were not significantly different in the three various-sized arteries or for the two myographs. Stereological estimates of SM cell volume, length, and diameter were based on counts of SM nuclei and their length. In evaluating the ring preparation of the vessel myographs, the damage due to the wires (20%) and cut edges (6.4%) was considered. The maximum active SM stress was approximately the same in the different-sized vessels with an average value of 3.14 X 10(5) N/m2. Since this stress is comparable to measurements made by others on different mechanical apparatus and consistent for the three arterial orders, these in vitro myographs should allow for valid comparison of arterial mechanical properties over the size range studied.

scholarly journals Rumen protein degradation and biosynthesis

1983 ◽  
Vol 50 (3) ◽  
pp. 569-582 ◽  
Author(s):  
L. Raab ◽  
B. Cafantaris ◽  
T. Jilg ◽  
K. H. Menke
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Rumen Fluid ◽  
Ammonia Concentration ◽  
Gas Production ◽  
Total N ◽  
Fluid Medium ◽  
The Difference ◽  
Fermentable Carbohydrates

1. A method is described for the determination of protein degradation based on measurements of ammonia concentration and gas production (Menke et al. 1979) when a feedingstuff was incubated with rumen fluid in vitro.2. NH3 liberated during incubation is in part used for microbial protein synthesis. Production of carbon dioxide and methane can be regarded as a measure of energy available for protein synthesis. The ratio, gas production: incorporation of NH3-nitrogen was estimated by addition of starch to the substrate. The response in gas production was linear in the range 0–200 mg starch, when starch was added to 0–200mg feedingstuff dry matter and 30 ml rumen fluid-medium mixture.3. Linear regression between NH3-N concentration (y, mg) and gas production (x, ml) yielded an intercept (b0) representing that amountof NH3-N which would be released when no fermentable carbohydrates were available and consequently no bacterial protein synthesis took place.4. The difference between this intercept b0 and NH3-N content in the blank (rumen fluid without substrate added) indicated the amount of NH3 liberated from protein and other N-containing compounds of the feedingstuff incubated. In vitro-degradable N (IVDN) was calculated as a proportion of total N by the equation:

The use of degradation characteristics of browse plants to predict intake and digestibility by goats

1993 ◽  
Vol 57 (2) ◽  
pp. 247-251 ◽  
Author(s):  
A. Kibont ◽  
E. R. Ørskov
Keyword(s):  
Regression Analysis ◽  
Rumen Fluid ◽  
Latin Square ◽  
Correlation Coefficients ◽  
Exponential Model ◽  
Gas Production ◽  
Lag Phase ◽  
In Vitro Gas Production

AbstractTwenty-five male goats weighing 16 (s.e. 1-5) kg and aged 15 months were used to measure the dry matter (DM) intake of five browse species namely Acacia albida, Tamarindus indica, Etanda africana, Anogeissus leiocarpus and Sterculia setigera in a growth trial lasting 16 weeks. This was followed by a digestion trial with five goats in a 5 × 5 Latin square with 10 days adaptation and a 5-day measurement period. The degradation characteristics of the browse were measured by incubating samples in nylon bags for 6, 24, 48 and 96 h in the rumens of three sheep fitted with rumen cannulae and given hay plus grass nuts. The exponential model P = a +b(l — ect) was fitted to the data. Rumen fluid from the sheep was also used as an inoculum to incubate the samples in vitro for 3, 6,12, 24, 48, 72 and 96 h. Nylon bag degradability results were compared with in vivo results and in vitro gas production. The mean DM intakes, apparent digestible DM intakes and growth rates were 0·60, 0·62, 0·55, 0·53 and 0·65 kg/day, 0·43, 0·43, 0·35, 0·34 and 0·49 kg/day and 55, 60, 49, 42 and 62 glday for A. albida, T. indica, E. africana, A. leiocarpus and S. setigera respectively. Using the degradation characteristics A, B and c in a multiple regression analysis, the correlation coefficients with DM intake, apparent DM digestibility, apparent digestible DM intake and growth rate were 0·99, 0·88, 0·92 and 0·99 respectively. The inclusion of a lag phase (L) instead of A in the regression analysis improved the prediction of apparent DM digestibility and apparent digestible DM intake. The correlation coefficients between DM loss in nylon bags and in vitro gas production at 6, 24 and 48 h incubation were 0·84, 0·83 and 0·90 respectively. The results indicate that it may be possible to predict DM and apparent digestible DM intakes of browse by goats from the rumen degradation characteristics.

scholarly journals Estimation of the degradability of dietary protein in the sheep rumen by in vivo and in vitro procedures

1985 ◽  
Vol 54 (2) ◽  
pp. 545-561 ◽  
Author(s):  
R. C Siddons ◽  
J Paradine ◽  
D. L. Gale ◽  
R. T. Evans
Keyword(s):  
Rumen Fluid ◽  
Flow Measurements ◽  
Fractional Rate ◽  
Outflow Rate ◽  
Bean Meal ◽  
Sheep Rumen ◽  
Soya Bean Meal ◽  
Microbial N

1. Estimates of degradability of nitrogen in the sheep rumen for a basal hay diet and for soya-bean meal (SBM), groundnut meal (GNM) and fish meal (FM), when given together with the hay, were determined from measurements of (1) duodenal N flow, (2) ammonia kinetics and (3) rumen N disappearance from polyester bags and rumen outflow rate. The ability of various in vitro procedures to predict in vivo N degradability was also examined.2. Four sheep were given a basal hay diet (800 g dry matter (DM) and 19 g N/d) either alone or supplemented with isonitrogenous amounts (15 g N/d) of SBM, GNM or FM. Duodenal non-ammonia-N flow (g/d) was increased more by FM (8.0) than by GNM (5.9) and SBM (5.8), whilst microbial N flow (g/d) was increased more by SBM (3.9) than by GNM (2.3) and FM (1.6). N degradability values calculated from these results were 0.88, 0.76 and 0.57 for the SBM, GNM and FM respectively. The corresponding value for hay was calculated to be 0.76.3. The irreversible loss of ammonia in the forestomachs (g N/d) was increased more by SBM (11.9) than by GNM (7.2) and FM (5.8) whilst ammonia outflow from the rumen (g N/d) was increased to a similar extent by all supplements ( I.1, 0.9 and 0.8 respectively), as was the amount of microbial N (g/d) synthesized from sources other than rumen ammonia (1.8, 2.0 and 1.9 respectively). N degradability values calculated from these results were 0.84, 0.54 and 0.45 for the SBM, GNM and FM respectively.4. The fractional rate of N disappearance (/h) when the feedstuffs were incubated in polyester bags in the rumen of sheep receiving the basal hay diet (800 g DM/d) was the highest for SBM (0,145) and lowest for FM (0.037), with the hay (0.082) and GNM (0.071) intermediate, whilst the fractional outflow rates from the rumen (/h) of the three supplements were similar (0.034, 0.038 and 0,030 for SBM, GNM and FM espectively). N degradability values calculated from these results were 0.82, 0.67 and 0.60 for the SBM, GNM and FM respectively; the value for the hay was 0.73.5. Of a number of in vitro procedures tested, only N solubility in sodium hydroxide and ammonia or total non-protein-N (NPN) production during incubation with rumen fluid in the absence of hydrazine sulphate ranked the supplements, although not the hay, in the same order as the in vivo degradability procedures. In terms of absolute values, N solubility in NaOH, at room temperature, gave estimates similar to those derived from the duodenal flow measurements; estimates derived from ammonia and total NPN production were lower.

Rumen degradability of organic matter, nitrogen and fibre fractions in forages

1990 ◽  
Vol 51 (3) ◽  
pp. 515-526 ◽  
Author(s):  
P. Susmel ◽  
B. Stefanon ◽  
C. R. Mills ◽  
M. Spanghero
Keyword(s):  
Organic Matter ◽  
Regression Analysis ◽  
Rate Constants ◽  
Dry Matter ◽  
Maize Silage ◽  
Sodium Dichromate ◽  
Outflow Rate ◽  
Main Component

ABSTRACTRumen degradability of dry matter (DM), organic matter (OM), nitrogen (N), neutral-detergent fibre (NDF), hemicellulose, cellulose and lignin was evaluated with the in situ technique for maize silage and cocksfoot, timothy, fescue, lucerne and meadow hays. The degradability of each of the six forages was studied separately, each forage being used in turn as the main component of the diet offered to four fistulated cows. For each forage 300 g were mordanted with sodium dichromate and placed in the rumen when the same forage was studied. Faecal grab samples were collected to measure the forage transit time. Digestibility was evaluated using both lignin as an indicator and by an in vitro method.Rumen outflow rate was higher for cocksfoot and lucerne hays than for maize silage and the meadow, timothy and fescue hays (P < 0·01). The effective degradabilities of DM and OM were higher in maize silage, fescue and lucerne than in cocksfoot, timothy or meadow hay (P < 0·01). Effective degradability of N was highest in lucerne and lowest in timothy and meadow hay (P < 0·01). The degradability of NDF, hemicellulose and cellulose for fescue was always the highest of the six forages (P < 0·01; P < 0·05; F < 0·01 respectively).Rumen outflow rate was statistically correlated with the c value of DM (r = 0·47), N (r = 0·54), NDF (r = 0·43) and hemicellulose (r = 0·43). High correlations were observed between rate constants of degradation of NDF and hemicellulose, cellulose or lignin (0·93, 0·75 and 0·79 respectively). The regression between in vitro and lignin-derived digestibility was highly significant (P < 0·001, r2 = 0·902 residual s.e. 0·017). The multiple regression analysis between lignin-based digestibility and degradability coefficients, effective degradability and coefficients of faecal chromium excretion was highly significant (r = 0·748; residual s.e. = 0·03).

scholarly journals In vitro estimation of rumen fermentable organic matter using rumen fluid and a cell free preparation of rumen fluid

1994 ◽  
Vol 42 (4) ◽  
pp. 343-356 ◽  
Author(s):  
J.W. Cone ◽  
A.H. Van Gelder ◽  
E.T. Veerman ◽  
A.M. Van Vuuren
Keyword(s):  
Organic Matter ◽  
Rumen Fluid ◽  
Good Prediction ◽  
Feed Composition ◽  
In Vitro Methods ◽  
In Situ Method ◽  
A Cell

The amount of microbial protein leaving the rumen is considered as a function of the amount of rumen-fermentable organic matter (FOM) in the rumen. FOM can be calculated using tables, or estimated by in situ incubation, but both methods have some drawbacks. In vitro methods were therefore developed to estimate FOM, using fresh rumen fluid or a cell-free preparation of rumen fluid. Results were compared with the in situ method and a method using chemical feed composition. The in vitro methods gave a good prediction of the in situ estimation of FOM for the majority of feeds. For some feeds rich in starch or fat, the correlation was poor. Because no in vivo data of FOM were available, it could not be determined whether the in vitro or in situ methods gave false results. However, arguments suggest that the in situ method is not suitable for some feeds.

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