scholarly journals Simulation of the effects of diet on the contribution of rumen protozoa to degradation of fibre in the rumen

1995 ◽  
Vol 74 (5) ◽  
pp. 617-634 ◽  
Author(s):  
Jan Dijkstra ◽  
Seerp Tamminga
Keyword(s):  
Mathematical Model ◽  
Feed Intake ◽  
Rumen Bacteria ◽  
Neutral Detergent Fibre ◽  
Rumen Protozoa ◽  
Intake Level ◽  
Metabolic Activities ◽  
Sugar Levels

A previously described mathematical model, that simulates the metabolic activities of rumen bacteria and protozoa, was used to examine the contribution of protozoa to neutral-detergent fibre (NDF) degradation in the rumen of cattle. Comparisons between predicted and experimentally observed NDF degradation showed general agreement. Further simulations were performed with diets containing variable proportions of concentrate (between 0 and 1 kg/kg diet DM) and at intake levels ranging between 5·3 and 21·0 kg DM/d. The simulated protozoal contribution to NDF degradation was 17–21% at the lowest intake level. Except for the all-concentrate diets, raising the feed intake level reduced this contribution to 5–3% at the highest intake level. The changes in contribution of protozoa to NDF degradation were related to variations in the fibrolytic bacteria: protozoa value and the NDF-degrading activities of protozoa predicted by the model. In simulations where dietary NDF levels were reduced and starch and sugar levels were increased independently, protozoal contribution to NDF degradation generally increased. These differences were reflected also in the generally increased protozoal contribution to NDF degradation predicted in response to a decreased roughage:concentrate value. The contribution of protozoa also generally declined in response to added N. These changes in predicted protozoal contribution to NDF degradation resulting from dietary variations provided possible explanations for the differences in rumen NDF degradation observed when animals are defaunated.

Measurement of protozoa, using phosphatidyl choline, and of bacteria, using nucleic acids, in the duodenal digesta of sheep fed chaffed lucerne hay (Medicago sativaL.) diets

1984 ◽  
Vol 102 (1) ◽  
pp. 33-44 ◽  
Author(s):  
A. John ◽  
M. J. Ulyatt
Keyword(s):  
Organic Matter ◽  
Dietary Intake ◽  
Feed Intake ◽  
Phosphatidyl Choline ◽  
Close Agreement ◽  
Rumen Bacteria ◽  
Once Daily ◽  
Rumen Protozoa ◽  
N Yield ◽  
Microbial N

SummaryThe use of phosphatidyl choline (PC) as a marker of protozoa in duodenal digesta was examined in sheep fed chaffed lucerne hay (Medicago sativaL.; 330–950 g organic matter/day) either once daily or hourly.PC was present in rumen protozoa (N:PC-P = 185±6·4) but was not detected in rumen bacteria. Dietary intake of PC was less than 5% of the daily passage of PC from the stomach (7·49 mg PC-P/day). A comparison of the SA of PC-P in protozoa and in duodenal digesta of sheep given a continuous intraruminal infusion of32P-orthophosphate showed that the proportion of dietary PC-P in duodenal digesta was negligible.The limitations and validity of PC as a marker of protozoa in duodenal digesta are discussed. The daily passage of protozoal N from the stomach (1·38 ± 0·125 g/day) estimated with PC was not affected by frequency of feeding but protozoal N yield (4·96 ± 0·509 g/kg organic matter apparently digested) declined with increasing feed intake.The SA of DNA-32P, RNA-32P and readily extractable phospholipid-32P (REPL-32P) in rumen protozoa, bacteria and duodenal digesta were similar, showing that the DNA, RNA and REPL-P in duodenal digesta were of microbial origin. A method is described for the estimation of bacterial REPL-P and bacterial N in duodenal digesta using DNA, RNA or DAPA as markers.The calculated total microbial REPL-P (bacterial plus protozoal) in digesta using DNA or RNA as markers was in close agreement with values obtained by direct measurement. It was estimated that protozoa contributed 22 and 14% of microbial REPL-P and microbial N, respectively. Bacterial REPL-P and bacterial N values estimated with DAPA as the marker were higher than values obtained with DNA or RNA. These results are discussed with regard to the use of these markers.

scholarly journals 172 Feed intake level and ambient temperature affect the body temperature of pigs exposed to heat stress.

2018 ◽  
Vol 96 (suppl_3) ◽  
pp. 295-296
Author(s):  
A Morales Trejo ◽  
D Antoine ◽  
A Valle-Fimbres ◽  
H Bernal Barragán ◽  
L Camacho ◽  
...  
Keyword(s):  
Heat Stress ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Feed Intake ◽  
The Body ◽  
Intake Level

METABOLISM OF RADIOMANGANESE AND RADIOZINC IN SHEEP — EFFECTS OF INTRARUMINAL DOSING WITH NITRILOTRIACETIC ACID

1979 ◽  
Vol 59 (2) ◽  
pp. 283-289 ◽  
Author(s):  
M. IVAN
Keyword(s):  
Urinary Excretion ◽  
Soft Tissues ◽  
Nitrilotriacetic Acid ◽  
Fecal Excretion ◽  
Rumen Bacteria ◽  
Tissue Samples ◽  
Rumen Protozoa

Two experiments were carried out with rams fed a concentrate diet containing 17 and 27 ppm (air dry basic) of manganese and zinc, respectively. In the first, fistulated rams were dosed intraruminally with 54Mn and samples of rumen contents were taken at different times after dosing. A peak uptake of radiomanganese by mixed rumen bacteria was obtained within 2 h after dosing. The uptake by rumen protozoa was almost unchanged during the first 7 h after dosing. In the second experiment, eight fistulated rams were divided into two groups. One group was dosed intraruminally with 180 mg of nitrilotriacetic acid (NTA) twice daily (before each feeding) for 1 mo and then both groups were dosed intraruminally with 54Mn and 65Zn and total 96-h fecal and urinary collection was commenced. Samples of rumen contents were taken at 2 h. Ninety-six hours after the administration of the radioisotopes the sheep were killed and tissue samples removed. Significantly lower uptakes of 54Mn and 65Zn by the rumen bacteria and protozoa were obtained in the NTA-treated sheep than in control sheep. The uptake of 54Mn by the rumen tissue was significantly higher in the NTA-treated sheep. There were no differences between treatments in the urinary excretion of radioisotopes, while fecal excretion of 54Mn and 65Zn tended to be lower in the NTA-treated sheep. It was apparent that the absorption of 54Mn and 65Zn was slightly increased by intraruminal dosing of sheep with NTA but the rate of uptake of radiomanganese by soft tissues tended to be lower in the NTA-treated sheep.

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.

The effects of fresh forages and feed intake level on digesta kinetics and enteric methane emissions from sheep

2014 ◽  
Vol 193 ◽  
pp. 32-43 ◽  
Author(s):  
K.J. Hammond ◽  
D. Pacheco ◽  
J.L. Burke ◽  
J.P. Koolaard ◽  
S. Muetzel ◽  
...  
Keyword(s):  
Feed Intake ◽  
Methane Emissions ◽  
Intake Level ◽  
Enteric Methane ◽  
Enteric Methane Emissions

Effects of feed intake level on efficiency of microbial protein synthesis and nitrogen balance in Boran steers consuming tropical poor-quality forage

2019 ◽  
Vol 73 (2) ◽  
pp. 140-157 ◽  
Author(s):  
Shimels Eshete Wassie ◽  
Asep Indra Munawar Ali ◽  
Daniel Korir ◽  
Klaus Butterbach-Bahl ◽  
John Goopy ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Feed Intake ◽  
Nitrogen Balance ◽  
Poor Quality ◽  
Microbial Protein ◽  
Microbial Protein Synthesis ◽  
Intake Level
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