ATP measurments in sheep rumen digesta using dimethyl sulfoxyde as an extraction reagent

Dimethyl sulfoxide (DMSO) has been used to extract adenosine 5’ triphosphate (ATP) from the rumen contents of sheep fed with three different diets : beet pulp, semipurified and grass-hay.After having determined the conditions for the utilization of DMSO (extraction within 15 min after sampling, storage of extracts at 0 °C and immediate assay or deep-freezing liquid nitrogen and storage at - 80 °C), this extractant was compared to cold H,S0 40.6N ; NRB (Lumac) and Nucleoline (CLV lnterbio). DMSO proved to be more efficient than the other three extractants. The relative effectiveness of sulfuric acid, compared to DMSO, was a mean of about 80 %, while that of NRB was 30 % and that of Nucleoline 8 % with wide inter-dietary variations. The new method developed can be applied to the study of ATP in vitro systems.Le diméthyl sulfoxyde (DMSO) a été utilisé comme agent d’extraction de l’ATP dansles contenus de rumen de moutons nourris avec 3 régimes différents (pulpes de betterave,semi-synthétique et foin).Après avoir précisé les conditions d’utilisation de ce réactif (extraction dans les 15 minsuivant le prélèvement, conservation des extraits à 0 °C et dosages dès la première heure, ou congélation dans l’azote liquide et conservation à - 80 °C) nous l’avons comparé auxagents d’extraction suivants : H2SO, 0,6N à froid, NRB (Lumac) et Nucléoline (CLVInterbio). Le DMSO s’est révélé plus efficace que ces trois autres agents. Par rapport auDMSO, l’efficacité relative de l’acide sulfurique est en moyenne d’environ 80 %, celle duNRB de 30 %, celle de la nucléoline de 8 % avec de grandes variations inter-régimes. Laméthode mise au point peut dès à présent être appliquée à l’étude de la production d’ATPdans les fermenteurs in vitro

Effect of different levels of phosphorous on rumen microbial fermentation and synthesis determined using a continuous culture technique

1. A continuous culture technique was used to study the phosphorus requirements of rumen micro-organisms. Solutions of artificial saliva containing 120, 80, 40 and 0 mg inorganic phosphorus (Pi)/1 were infused into the reaction vessels previously inoculated with rumen contents, resulting in Pi concentrations in the vessel contents of 48, 28, 4 and < 1 mg/l respectively. Various fermentative and synthetic characteristics were examined.2. In the vessel contents, concentrations of protozoa (about 0.9 x 105/ml) were not significantly affected by pi concentration. Total volatile fatty acids (VFA) produced averaged about 6.83 mmol/h with Pi levels of 48 and 28 mg/l. Reduction in Pi concentrations to 4 and < 1 mg/l resulted in significant reductions in total VFA to approximately 6.25 and 3.75 mmol/h respectively, accompanied by a rise in pH from 6.5 to 7.3. Ammonia-nitrogen values, which averaged about 131 mg/l at the higher Pi concentrations, also increased with the lowest level of Pi to about 240 mg/l. ATP concentrations averaged about 14 μmol/l at the highest Pi concentration and fell progressively with each reduction in Pi concentration to a final value of 2.5μmol/1 with the Pi level < 1 mg/1.3. At Pi concentrations of 48 and 28 mg/l, the digestibilities of xylose, arabinose and cellulose-glucose were maintained at about 0.90, 0.62 and 0.70 g/g input respectively. At lower Pi, concentrations these digestibilities fell significantly and corresponding values at Pi < 1 mg/l were 0.73, 0.41 and 0.31 respectively. Starch digestion was unaffected by Pi concentrations and remained at about 0.90 g/g input.4. The amount of microbial-N synthesized averaged 0.48 g/d and was maintained with Pi concentrations down to 4 mg/l. There was, however, a significant reduction to 0.26 g/d with Pi concentrations of < l mg/l. The effiency of microbial protein synthesis was variable but averaged approximately 25 g N/kg total carbothdrate fermented.5. It was estimated that the minimum Pi concentrations required in rumen fluid in vivo to maintain maximum degradative and synthetic microbial activities was in the range 75–100 mg/l and that the over-all P requirement of the microbes was of the order of 5.1 g/kg apparently digested organic matter intake

Effects of phosphorus deficiency on rumen microbial activity associated with the solid and liquid phases of a fermentor (Rusitec)

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Influence du niveau d'apport de phosphore sur les teneurs en adénosine 5' triphosphate et en acides gras volatils du milieu de rumen dans un système de fermentation continu

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Effet de quelques facteurs physico-chimiques sur l'adhésion à la cellulose de deux espèces bactériennes cellulolytiques du rumen

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Utilisation de l'azote 15 pour la mesure de la protéosynthèse microbienne dans les phases solide et liquide d'un fermenteur semi-continu (Rusitec)

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Influence de l'addition de phosphore sur la digestion d'une paille traitée à l'ammoniac par les microorganismes du rumen en fermenteur semi-continu

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Effets d'une sub-carence en phosphore sur divers paramètres de l'activité cellulolytique de Bacteroides succinogenes

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