scholarly journals Some factors influencing the chemical composition of mixed rumen bacteria

1974 ◽  
Vol 31 (1) ◽  
pp. 27-34 ◽  
Author(s):  
R. H. Smith ◽  
A. B. Mcallan
Keyword(s):  
Chemical Composition ◽  
Dry Matter ◽  
Rumen Bacteria ◽  
Host Animal ◽  
Adult Cattle ◽  
Total N ◽  
Adult Sheep ◽  
Factors Influencing ◽  
Mixed Bacteria ◽  
Ciliate Protozoa

1. Sheep, cows and calves fitted with rumen cannulas were given diets mostly containing 10–16 g nitrogen/kg dry matter and consisting of roughage and cereals. Mixed bacteria were separated from samples of their rumen contents.2. Bacteria taken 4–6 h after a feed from calves which were kept in an experimental calf-house with no contact with adult animals (environment A) contained more α-dextran, less total N and higher nucleic acid:total N ratios than similar bacteria from calves reared in contact with adult sheep (environment C) but otherwise treated in an identical way.3. Mixed bacteria taken 4–6 h after a feed from sheep and cows were similar in composition, with respect to nitrogenous components, to those from the ‘environment C’ calves. This composition did not vary significantly when diets containing differing proportions of roughage were given.4. The ‘environment A’ calves were free of ciliate protozoa. When they were placed in contact with, and were inoculated with rumen contents from, adult cattle (environment B), they rapidly developed a normal protozoal population and the chemical composition of their rumen bacteria became like that of the bacteria from the ‘environment C’ calves.5. Mixed bacteria taken just before a feed, from either cows or ‘environment A’ calves, showed significantly lower RNA-N:total N ratios and slightly (but not usually significantly) higher DNA-N:total N ratios than bacteria taken 4–6 h after feeding. Total N contents of the bacteria did not change consistently with time after feeding.6. The possible significance of these differences in relation to the nutrition of the host animal is discussed.

Biphasic breakdown of peptides by rumen bacteria

1996 ◽  
Vol 1996 ◽  
pp. 237-237
Author(s):  
R.J. Wallace
Keyword(s):  
Dry Matter ◽  
Rumen Fluid ◽  
Rumen Bacteria ◽  
Mixed Diet ◽  
Supernatant Fluid ◽  
Differential Centrifugation ◽  
Ammonia Production ◽  
Protein Breakdown ◽  
Adult Sheep ◽  
Mixed Bacteria

Excessive protein breakdown and ammonia production often lead to inefficient N utilisation in ruminants. Peptides are intermediates in the breakdown process. The aims of this study were to characterize peptidase activities of rumen bacteria and to determine which species of bacteria were responsible for the different steps of peptide breakdown in the rumen.Four rumen-fistulated adult sheep received a mixed diet (hay, barley, molasses, fishmeal and minerals and vitamins: 500, 99.5, 100, 91 and 9.5 g/kg dry matter respectively) fed in equal meals of 500 g at 0800 and 1600 h. Rumen fluid was removed 3 h after the morning feeding, strained, and mixed bacteria were prepared by differential centrifugation. Bacteria were sonicated and debris was removed by centrifugation. Peptidase activities were determined on the supernatant fluid.

scholarly journals A comparison of the chemical composition of mixed bacteria harvested from the liquid and solid fractions of rumen digesta

1983 ◽  
Vol 50 (3) ◽  
pp. 701-709 ◽  
Author(s):  
R. J. Merry ◽  
A. B. McAllan
Keyword(s):  
Chemical Composition ◽  
Dry Matter ◽  
Metabolizable Energy ◽  
Diaminopimelic Acid ◽  
Microbial Protein ◽  
Microbial Synthesis ◽  
Total N ◽  
Associated Bacteria ◽  
Physical Form ◽  
Mixed Bacteria

1. Steers, equipped with simple rumen cannulas, were given diets of approximately equal parts of rolled barley and straw supplemented with urea. The diets provided sufficientestimated rumen degradable nitrogen (RDN: RDN: metabolizable energy values of 1:3) to maintain maximum microbial synthesis. In some experiments Na235SO4was introduced into the rumen to label microbial protein.2. Rumen digesta samples were taken before feeding and mixed rumen bacteria were separated from the solid (solid-associated bacteria; SAB) and liquid (liquid-associated bacteria; LAB) fractions of digesta. The most effective method of removing SAB from the fibre was a combination of homogenizing and pummelling. This process did not affect the physical form or chemical composition of the bacteria.3. Samples of SAB contained significantly (P≤ at least 0·05) less ash, total N, RNA and diaminopimelic acid (DAP) and significantly (P≤ 0·01) more lipid than samples of LAB. Concentrations (g/kg dry matter) of ash, total N, RNA, DAP and lipid in SAB were approximately 87, 70, 35, 2.2 and 245 respectively. Corresponding values for LAB were 157, 80, 50, 3.8 and 124 respectively.4. RNA-N: total N and DAP-N: total N values in SAB were significantly lower than those in LAB (P≤ 0·05 and 0·02 respectively).35S: totalN values were similar in both groups of bacteria. The importance of differences in constituent: total N values in the two groups of bacteria in relation to their use as indices of microbial protein synthesis is discussed.

Biphasic breakdown of peptides by rumen bacteria

1996 ◽  
Vol 1996 ◽  
pp. 237-237
Author(s):  
R.J. Wallace
Keyword(s):  
Dry Matter ◽  
Rumen Fluid ◽  
Rumen Bacteria ◽  
Mixed Diet ◽  
Supernatant Fluid ◽  
Differential Centrifugation ◽  
Ammonia Production ◽  
Protein Breakdown ◽  
Adult Sheep ◽  
Mixed Bacteria

Excessive protein breakdown and ammonia production often lead to inefficient N utilisation in ruminants. Peptides are intermediates in the breakdown process. The aims of this study were to characterize peptidase activities of rumen bacteria and to determine which species of bacteria were responsible for the different steps of peptide breakdown in the rumen.Four rumen-fistulated adult sheep received a mixed diet (hay, barley, molasses, fishmeal and minerals and vitamins: 500, 99.5, 100, 91 and 9.5 g/kg dry matter respectively) fed in equal meals of 500 g at 0800 and 1600 h. Rumen fluid was removed 3 h after the morning feeding, strained, and mixed bacteria were prepared by differential centrifugation. Bacteria were sonicated and debris was removed by centrifugation. Peptidase activities were determined on the supernatant fluid.

Effects of feeding frequency and level of feed intake on chemical composition of rumen bacteria

1984 ◽  
Vol 102 (1) ◽  
pp. 45-57 ◽  
Author(s):  
A. John
Keyword(s):  
Feed Intake ◽  
Dry Matter ◽  
Cell Mass ◽  
Rumen Bacteria ◽  
Total N ◽  
Once Daily ◽  
Cell Composition ◽  
Total Dna ◽  
Feeding Regimen ◽  
Pool Sizes

SummaryCell mass (dry matter per cell) and cell composition (concentrations of DNA, RNA, phospholipids, total N, a-dextran, diaminopimelic acid and 18 common amino acids) of rumen bacteria were measured at various times after feeding sheep chaffed lucerne hay (Medicago sativaL.) once daily. Cell composition was measured with sheep fed once hourly. Total DNA and RNA pool sizes in the rumen were also measured.While cell composition was not affected by level of feed intake (700 gv. 1050 g dry matter/day), total DNA, RNA and D.M. pool sizes in the rumen increased with increasing feed intake. With sheep on the once daily feeding regimen relative rumen pool sizes in rumen digesta at various times after feeding were: RNA, 4 > 14 > 0 h; DNA, 4 and 14 > 0 h; D.M. 4 > 14 > 0 h. With the hourly feeding regimen pool sizes were similar to the averaged daily values for sheep fed once daily.When sheep were fed once daily bacterial cell mass, DNA and phospholipid concentrations peaked at 12–14 h after feeding and subsequently decreased to the 0 h value. RNA concentration was maximal at about 4 h after feeding and declined to near the 0 h value at about 14 h. RNA concentrations in bacteria were highly correlated with gas production rates by whole rumen digesta. The ratio RNA:DNA was highest shortly after feeding, decreased to below the 0 h value at about 14 h and then increased to the 0 h value. The relative concentrations of a-dextran in bacteria were: 4 > 14 > 0 h. Cell composition witli sheep fed hourly tended to reflect the averaged daily values for sheep fed once daily.These results are discussed with regard to changes in estimated fermentation rate and pool size of bacteria in the rumen. It is suggested that changes in average composition (DNA, RNA, total N and RNA: DNA ratio) of mixed rumen bacteria reflect changes in the average growth rate of the population.

scholarly journals Digestibilities of nitrogen compounds in rumen bacteria and in other components of digesta in the small intestine of the young steer

1977 ◽  
Vol 38 (2) ◽  
pp. 207-216 ◽  
Author(s):  
D. N. Salter ◽  
R. H. Smith
Keyword(s):  
Small Intestine ◽  
Nitrogen Compounds ◽  
Rumen Bacteria ◽  
Protein Concentrate ◽  
Total N ◽  
Mean Values ◽  
Leaf Protein Concentrate ◽  
Wheat Leaf ◽  
Mixed Bacteria ◽  
Protein Free Diet

1. Mixed bacteria were obtained from the rumen contents of steers and were taken at different times after the animals had been given different feeds. The feeds contained [15N]urea and in some experiments Na235SO4 so that the bacteria were labelled with these isotopes.2. Samples of labelled bacteria were subjected to a simulated abomasal digestion with pepsin and the digests were infused with a non-absorbed marker, polyethylene glycol, into the duodenums of test steers equipped with re-entrant ileal cannulas. Except for samples taken after a 24 h fast, which sometimes gave somewhat lower values, mean values for digestibilities of 15N and 35S in the small intestine were 0.79 and 0.85 respectively.3. The corresponding value for the digestibility of 15N in similarly-treated wheat-leaf protein concentrate was 0.86.4. Net digestibilities of total N in the small intestine of the test steers when they were given either a mainly protein-free diet of straw, tapioca and urea or a diet of flaked maize and hay were approximately 0.62.5. From these and other values it was calculated that approximately 5.2g intestinally-secreted endogenous N/d flowed through the ileum of a 100 kg steer.

scholarly journals Fractionation of carbohydrates and nitrogenous constituents of late-crop corn silages ensiled with different specific masses

2017 ◽  
Vol 38 (1) ◽  
pp. 491 ◽  
Author(s):  
Fernanda Hentz ◽  
João Pedro Velho ◽  
José Laerte Nornberg ◽  
Ione Maria Pereira Haygert-Velho ◽  
Éderson Luis Henz ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Experimental Design ◽  
Dry Matter ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Ether Extract ◽  
Soluble Fiber ◽  
Total N ◽  
Protein System ◽  
Linear Manner

The present study aimed to evaluate the chemical composition of carbohydrates and nitrogenous fractions of late-crop corn silages with different specific masses (SM; 90, 134, 172, and 214 kg dry matter m-3). The silage was held in 20-L mini-silos, and the experimental design was completely randomized, with four replications (mini-silos) per treatment. Fractionation was performed according to The Cornell Net Carbohydrate and Protein System (CNCPSv5.0). The SM of the silage significantly affected the contents of ether extract ( ? = 1.718 + 0.0041?SM; P = 0.009; R2 = 39.2), soluble sugars ( ? = 0.9502 - 0.003445?SM; P < 0.001; R2 = 59.9), and soluble fiber ( ? = -0.4731 + 0.01158?SM; P = 0.025; R2 = 31.2). In addition, SM also affected carbohydrate fraction B1 in a linear manner ( ? = 14.88 + 0.2566?SM; P = 0.043; R2 = 38.4), whereas the remaining fractions were unaffected. Furthermore, no change was observed in total N ( ? = 2.003 - 0.01065?SM + 0.000036?SM2; P = 0.041; R2 = 38.8), non-protein N ( ? = 1.436 - 0.01103?SM + 0.000036?SM2; P = 0.060; R2 = 35.1), soluble N ( ? = 1.715 - 0.01450?SM + 0.00005?SM2; P = 0.024; R2 = 43.8), or neutral detergent insoluble N ( ? = 0.4979 - 0.001057?SM; P < 0.001; R2 = 70.6). The results also contributed to the differences in fractions A ( ? = 66.47- 0.5291?SM + 0.00174?SM2; P = 0.095; R2 = 30.4), B2 ( ? = 6.78 + 0.05857?SM; P = 0.076; R2 = 20.8), and B3 (? = 19.03 - 0.05565?SM; P = 0.018, R2 = 34,1) of the Cornell model. In the present study, differences in the compression (i.e., SM) of corn silages caused changes in the contents of soluble sugar and nitrogenous constituents; however, SM alone did not explain the entire preservation of the ensiled material.

scholarly journals Carbohydrate metabolism in the ruminant

1974 ◽  
Vol 31 (1) ◽  
pp. 77-88 ◽  
Author(s):  
A. B. McAllan ◽  
R. H. Smith
Keyword(s):  
Carbohydrate Metabolism ◽  
Dry Matter ◽  
Rumen Bacteria ◽  
Similar Composition ◽  
Average Value ◽  
Mixed Bacteria

1. Samples of mixed bacteria were separated from rumen digesta taken from calves, kept out of contact with adult animals, and from sheep and cows.2. For calves receiving a diet made up of equal amounts of roughage and cereals with 13–16 g nitrogen/kg dry matter, samples of mixed bacteria taken 4–6 h after feeding contained, on average, 140 g glucose in α-linked polymers (α-dextran), 25 g galactose and a total of 25 g other non-glucose, non-galactose sugars (mainly rhamnose, ribose and mannose) in combined forms per kg dry matter.3. The α-dextran content of similar bacteria samples from sheep or cows receiving diets of similar composition was 70 g/kg dry matter. Samples from animals receiving all-roughage diets contained only 25 g α-dextran/kg dry matter, but those from cows given more than 70% of their ration as concentrates (mainly cereal) contained 150 g α-dextran/kg dry matter.4. Addition of supplementary protein or urea to cereal–roughage diets given to calves greatly depressed the amount of α-dextran in the rumen bacterial samples to an average value of 60 g/kg dry matter.5. Samples taken before a morning feed (i.e. after 16 h fasting) contained less α-dextran than samples taken 4–6 h after feeding for both calves and cows.6. Under different conditions, variations in the amounts of galactose in rumen bacteria sometimes paralleled variations in α-dextran. Amounts of other non-glucose sugars did not vary greatly.7. It was estimated, from a comparison of the compositions of rumen bacteria and duodenal contents, that, in the latter, the rhamnose, ribose and mannose came mainly from the bacteria, the arabinose, xylose and cellulose-glucose mainly from the diet and the galactose and α-dextran-glucose from both sources.

scholarly journals Chemical composition and ruminal digestion of corn silage with Morus alba L. foliage

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Regulo Jimenéz-Guillén ◽  
David Heriberto Noriega Cantú ◽  
Saúl Rojas-Hernández ◽  
Jaime Olivares Pérez ◽  
Abel Villa-Mancera ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Crude Protein ◽  
Dry Matter ◽  
Morus Alba ◽  
Corn Silage ◽  
Total N ◽  
Dry Matter Digestibility ◽  
Silage Fermentation ◽  
Ruminal Digestion

Chemical composition and ruminal digestion parameters were mea- sured in the silage of the whole corn plant (Zea mays L.) mixed with mulberry foliage (Morus alba L.) in ratio of 100:0, 80:20, 60:40, 40:60, 20:80 and 00:100% of fresh forage weight, respectively. The 40:60 ratio of corn: mulberry increased crude protein content (CP = 14.28%) and decreased hemicellulose (12.15%), neutral (NDF = 28.00%) and acidic (ADF = 15.85%) detergent fiber, compared to 100: 0% ratio, respectively, which led to a 21.3% increase in in vitro dry matter digestibility (IVDMD). Also ammoniacal nitrogen 7.40% (NH3-N/total N) was higher in the ratio 40:60%, with pH of 4.19 which is normal for silages, which translates the buffer activity correct of ammonia and its importance for silage fermentation stability. The correlation (r = 0.61, p < 0.001) indicated that at higher CP content, higher is IVDMD and hemicellulose (r = -0.99), ADF (r = -0.98) and NDF (r = -0.98) indicated that these fibrous compounds decreased IVDMD (p < 0.001). The regression showed that the increase in content CP (0.555%, p < 0.01) and IVDMD (0.3391%, p < 0.001) with the decrease of NDF (-0.3526%), ADF (-0.1623%) and hemicellulose (-0.1903%) (p < 0.001) in mixed mini silos, was attributed to mulberry foliage addition. It is concluded that the contribution of dry matter and nitrogen of mulberry, decreased the fiber content and increased digestibility parameters of silage when it is elaborated in ratio of 40:60 corn and mulberry, respectively.

Chemical composition of clamped and baled grass silages harvested in England and Wales and relationships between dry matter content, pH and volatile N

1999 ◽  
Vol 132 (2) ◽  
pp. 163-172 ◽  
Author(s):  
M. FIELD ◽  
D. WILMAN ◽  
D. J. C. JONES
Keyword(s):  
Chemical Composition ◽  
Crude Protein ◽  
Dry Matter ◽  
Matter Content ◽  
Dry Matter Content ◽  
Total N ◽  
England And Wales ◽  
Straight Line ◽  
The Mean ◽  
The Relationship

The paper reports a study of the chemical composition of 25400 grass silages produced in England and Wales, of which 1040 were from the period 1961–63, 17900 (15480 clamped and 2420 baled) were from 1982–88 and 6460 (5640 clamped and 820 baled) were from 1992–93. A sample of each silage had been analysed for dry matter (DM), pH, crude protein (CP) and volatile N and in most cases for ash.The baled silages were drier on average than the clamped silages, with a wider spread of DM contents. The clamped silages with the lowest pH on average were those with a DM content of c. 240 g/kg; clamped silages wetter than this were progressively higher in pH with reduction in DM content; clamped and baled silages drier than 240 g/kg were progressively higher in pH with increase in DM content, up to pH 5·9 in baled silages of 580 g DM/kg. At a given DM content pH was on average 0·6 units higher in baled than in clamped silages. The ash content of baled silages was similar to that of clamped silages. There was an increase in the mean CP content of clamped silages between 1961–63 and 1992–93 and a reduction in the proportion of CP which was volatile. The relationship between DM and volatile N as a proportion of total N was a curve rather than a straight line, with the steepest part of the curve at the lower end of the DM range. The wet silages harvested in 1961–63 were particularly high in volatile N. At a given DM content in the range 170–320 g/kg, volatile N was rather higher in baled than in clamped silages in both 1982–88 and 1992–93. Clamped silages with a DM content of at least 250 g/kg and baled silages with a DM content of at least 310 g/kg were typically well preserved in the sense of having <100 g volatile N/kg total N.

Reducing rumen methane emissions through elimination of rumen protozoa

1999 ◽  
Vol 50 (8) ◽  
pp. 1321 ◽  
Author(s):  
R. S. Hegarty
Keyword(s):  
Dry Matter ◽  
Methane Emissions ◽  
Commercial Application ◽  
Partial Pressure Of Oxygen ◽  
Host Animal ◽  
Fatty Acid Production ◽  
Fermenting Bacteria ◽  
Methanogen Population ◽  
Hydrogen Availability ◽  
Ciliate Protozoa

Methanogens living on and within rumen ciliate protozoa may be responsible for up to 37% of the rumen methane emissions. In the absence of protozoa, rumen methane emissions are reduced by an average of 13% but this varies with diet. Decreased methane emissions from the protozoa-free rumen may be a consequence of: (1) reduced ruminal dry matter digestion; (2) a decreased methanogen population; (3) an altered pattern of volatile fatty acid production and hydrogen availability; or (4) increased partial pressure of oxygen in the rumen. The decline in methanogenesis associated with removal of protozoa is greatest on high concentrate diets and this is in keeping with protozoa being relatively more important sources of hydrogen on starch diets, because many starch-fermenting bacteria do not produce H2. Because protozoa also decrease the supply of protein available to the host animal, their elimination offers benefits in both decreasing greenhouse gas emissions and potentially increasing livestock production. Strategies for eliminating protozoa are reviewed. None of the available techniques is considered practical for commercial application and this should be addressed.

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