A stringent test for the artificial rumen

1962 ◽  
Vol 13 (2) ◽  
pp. 343 ◽  
Author(s):  
FV Gray ◽  
RA Weller ◽  
AF Pilgrim ◽  
GB Jones

In each of three experiments the acetic, propionic, and butyric acids in the rumen of a sheep were labelled with 14C and a sample of the rumen contents was removed to an artificial rumen so that fermentations of the same substrates could be conducted simultaneously in vivo and in vitro. The in vitro fermentations were carried out in a specially designed artificial rumen of the "permeable" type in which the volume of the contents was kept constant while a continuous supply of artificial saliva was introduced. The relationships between the specific activities of the volatile fatty acids during a period of 2 to 3 hr indicated that the relative rates of formation of the acids were similar in the two systems, although in each experiment the fermentation appeared to proceed more slowly in vitro. It is considered that the procedure constitutes a stringent test for the correct functioning of an artificial rumen.

2012 ◽  
Vol 57 (No. 1) ◽  
pp. 10-18 ◽  
Author(s):  
F. Leiber ◽  
C. Kunz ◽  
M. Kreuzer

It was hypothesized that buckwheat, especially its flowers, influences foregut fermentation in ruminant animals because it is rich in phenolic compounds. The entire fresh aerial buckwheat herb, or its parts (leaves, stems, flowers and grain), were incubated for 24 h together with pure ryegrass (1:1, dry matter basis) in an in vitro ruminal fermentation system (Hohenheim Gas Test). Additionally ryegrass, supplemented with 0, 0.5, 5, or 50 mg rutin trihydrate/g dry matter, was incubated. Contents of extractable phenols (g/kg dry matter) were the highest in buckwheat flowers (88), followed by leaves (63), and the lowest in ryegrass (8). The levels of production of total gas and volatile fatty acids demonstrated that the nutritional value of buckwheat was slightly lower than that of ryegrass. Compared to ryegrass alone, ruminal transformation of dietary protein-N <br />into ammonia was lower with 50 mg rutin, buckwheat flowers and buckwheat leaves. Thus, these treatments appeared to have partly protected dietary protein from ruminal degradation. Rutin, at the highest level, buckwheat flowers and the total aerial fraction of the buckwheat plant suppressed methane per unit of total gas by &gt; 10%, either at elevated (rutin) or reduced total gas volume. This indicates that the ways of the influence on the ruminal fermentation pattern differed between pure rutin and buckwheat. In vivo studies have to confirm these potentially beneficial effects of buckwheat if used as forage for ruminants and clarify the role of further phenolic compounds present in buckwheat. Abbreviations: DM = dry matter, HGT = Hohenheim Gas Test, NDF = neutral detergent fibre, TEP = total extractable phenols, VFA = volatile fatty acids


1959 ◽  
Vol 31 (1) ◽  
pp. 315-320
Author(s):  
Martti Lampila ◽  
Ilmari Poijärvi

On a diet containing fodder sugar beets the proportion of butyric acid in the mixture of the volatile fatty acids of the rumen contents was found to be unusually high. When the rumen contents were incubated at different pH-levels in vitro, it was found that the proportion of butyric acid in the volatile fatty acid mixture produced increases when the pH decreases. Using polyethylene glycol as a reference substance, the transfer of fluid through the reticulo-omasal orifice was studied. The transfer of volatile fatty acids into the omasum is calculated on the basis of the fluid flow and on the acid concentrations of the fluid in the lower anterior part of the contents.


Author(s):  
O. Vozna ◽  
N. Motko

Three groups of rabbits of different origin (29, 27 and 28 animals; 3 or 4–6 months of age) were slaughtered, their caecal contents analyzed and used for inoculation of in vitro cultures. Whereas the caecal pH, dry matter percentages and acetate molar proportions in caecal volatile fatty acids (VFA) were relatively stable, molar proportions of other VFA varied considerably. In in vitro incubations, caecal parameters varied somewhat less than in vivo. Methane production varied much more than total VFA production. No non-methanogenic rabbit, however, was found. The hydrogen recovery correlated Significantly with the methane production and, in two out of three groups of rabbits, also with the propionate molar percentage. The caecal pH was inversely related to VFA concentration.


1974 ◽  
Vol 32 (2) ◽  
pp. 341-351 ◽  
Author(s):  
R. A. Weller ◽  
A. F. Pilgrim

1. A procedure for sampling digesta from within the omasal canal of sheep given a variety of roughage diets was used to enable comparison to be made of the composition of effluent from the reticulo-rumen with that of rumen fluid.2. Concentrations of protozoa in effluents, relative to a soluble marker continuously infused intraruminally, were usually less than 20% of corresponding rumen fluid concentrations. It was estimated that the amount of protozoal nitrogen leaving the rumen represented less than 2% of dietary N.3. Passage of volatile fatty acids (VFA) from the rumen in effluent was less than 75% of that indicated by rumen concentrations.4. A continuous, in vitro fermentation system was developed, in which outputs of protozoa were comparable with in vivo outputs.


1981 ◽  
Vol 45 (3) ◽  
pp. 567-578 ◽  
Author(s):  
G. Stanier ◽  
A. Davies

1. The effects of a methane inhibitor, ICI 111075, and a propionate enhancer, monensin, were studied using in vitro continuous fermenters.2. Both compounds increased the yield of substrate energy, carbon and hydrogen in volatile fatty acids (VFA). This was mainly due to an increase in the molar proportion of propionic acid.3. Improved yields of VFA were accompanied by reductions in methane production and microbial yield.4. Since published information showed that monensin reduced rumen dilution rate in vivo an analogous in vitro system was proposed in which a high dilution rate control fermenter was compared with a monensin treated fermenter set to run at a low dilution rate.5.Results showed that the general intrinsic microbial activity of the chemical manipulators was not affected by changes in dilution rate. Changing dilution rate in addition to chemical treatment however resulted in substantial modifications in the net effect on the fermentation.6. The practical implications of reducing rumen dilution rate as a side effect of chemically manipulating the rumen fermentation could involve changes in food intake, increased importance of secondary fermentations and a reduced effect of nutrients not degraded in the rumen.


1945 ◽  
Vol 22 (1-2) ◽  
pp. 51-62
Author(s):  
S. R. ELSDEN

1. Acetic, propionic and butyric acids are the main volatile fatty acids in the rumen of the sheep. Acetic acid accounts for 55-75% of the total. 2. Cellulose, glucose and lactic acid are rapidly fermented in vitro by rumen contents with the production of acetic, propionic and butyric acids. Pro-pionic acid is the major component in all cases: very little if any butyric acid is formed from cellulose. 3. The in vitro fermentation of glucose closely resembles the in vivo. 4. The in vitro fermentation of dried grass yields the same three acids, but with acetic acid predominating. 5. Members of the genus Propionibacterium have been isolated from the rumen, and evidence is presented to show that these organisms are responsible for the production of the propionic acid found in the rumen. 6. The dietary history of the animal is shown to influence the rate at which glucose is fermented in the rumen, and the composition of the rumen microflora.


2005 ◽  
Vol 93 (4) ◽  
pp. 479-484 ◽  
Author(s):  
J. A. Gómez ◽  
M. L. Tejido ◽  
M. D. Carro

Two incubation trials were carried out with the rumen-simulation technique (RUSITEC). In each trial, four vessels received a diet of grass hay and concentrate (600 and 400 g/kg DM, respectively; diet F), and the other four were fed a diet composed of concentrate and barley straw (900 and 100 g/kg DM, respectively; Diet C). Vessels were given 20 g of the corresponding diet daily, and half of them were supplemented with disodium malate to achieve a final concentration of 6.55 mM. There were no effects (P>0·05) of malate either on pH or on the daily production of NH3-N, but malate treatment increased (P<0·05) DM, neutral detergent and acid detergent fibre disappearance after 48 h incubation. The daily production of propionate and butyrate increased (P<0·001), and the ratio CH4:volatile fatty acids decreased (P<0·001) by supplementing both diets with malate. Whereas adding malate to the F diet produced an increase in acetate production (P=0·011) and the growth of solid-associated micro-organisms (P=0·037), no effects (P>0·05) were observed for diet C. For both diets, there were no differences (P>0·05) between treatments in the daily flow of liquid-associated micro-organisms measured using15N as a microbial marker. These results indicate that malate stimulated thein vitrofermentation of both diets by increasing the apparent disappearance of the diet and decreasing the ratio of CH4:volatile fatty acids, but a greater response was observed with diet F. If these results are confirmedin vivo, malate could be used as a feed additive for ruminants fed diets containing medium proportions of forage (i.e. dairy animals) and not only in animals fed high-concentrate diets, as has so far been proposed.


Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 92-OR ◽  
Author(s):  
WEI HUANG ◽  
YONG XU ◽  
YOUHUA XU ◽  
LUPING ZHOU ◽  
CHENLIN GAO

Sign in / Sign up

Export Citation Format

Share Document