Adenosine 5′-triphosphate and adenylate energy charge in sheep digesta

Abstract

SUMMARYThe concentrations of adenosine 5′-mono-, -di-, and -triphosphate (AMP, ADP and ATP) in sheep digesta were measured by a new bioluminescence method. ATP in rumen digesta varied with time after feeding and diet, and most markedly according to the size of the population of ciliate protozoa: the ATP content of rumen digesta from ciliate-free sheep was less than a quarter of that of faunated animals receiving the same diet. The adenylate energy charge (EC) (ATP + ADP/[ATP + ADP + AMP]), an indicator of metabolic activity, was high (0·77–0·94) in all rumen samples, but did not appear to be as useful a measurement of activity as ATP alone. As digesta passed along the alimentary tract, the ATP content decreased progressively, from 0·9–2·2 μmol/g dry matter in the rumen to 0·5–1·0μmol/g in the abomasum and duodenum, 07middot;03–0·08 μmol/g in ileal digesta and 0·01–0·02 μmol/g in faeces. EC also tended to decrease, further emphasizing the large decrease in microbial activity which occurs in the hindgut.

Digestion of a dehydrated lucerne/barley diet (70:30) in defaunated, Isotricha-monoinoculated and mixed-fauna-inoculated rumen in sheep

“…The very low values of adenylic nucleotides we observed, compared to those of Wallace and West (1982) and Erfle et al (1986), could have been due to losses during sampling, although extractions were done no more than 8 min after rumen contents were removed from the rumen, or to the disturbance of rumen microbes related to large amounts of highly fermentable starch. A more plausible reason is that a large majority of microbes were eliminated from our liquid samples during the filtration of solid particles.…”

The effect of a rumen microbial fermentation on urea and nitrogen metabolism of sheep nourished by intragastric infusion

“…In these, glucose inputs to the rumen were increased weekly and the effect of reducing agents on the establishment of rumen microbial populations was examined. Cysteine hydrochloride and Na2S.9H20, both separately and together, were infused into the rumen in amounts calculated to provide final concentrations (w/v) of 0 025 % of each in rumen fluid (Marounek & Wallace, 1984) and their effects on fermentative activity at different inputs of glucose were assessed by reference to the concentrations of ATP in rumen fluid (Wallace & West, 1982 [21][22][23][24][25] and the sampling of blood and rumen contents was on days 27 and 28. Additional samples of rumen contents (usually three samples per day) were taken for the measurement of urease (EC 3.5.1.5) activity and of ATP concentrations in rumen fluid: these samples were taken on days 13, 15 and 17 in periods 1 and 3 and on days 20, 23 and 28 in period 2.…”

ATP measurement in sheep rumen digesta using dimethyl sulfoxide as an extraction reagent

“…This variation has been related to the digestibility of the diet (Wolstrup and Jensen, 1976 ;Forsberg and Lam, 1977 ;Wallace and West, 1982) (Forsberg and Lam, 1977) Accepte en juillet 1984.…”

“…This method has been used successfully in rumen fluid (Forsberg and Lam, 1977 ;Wallace and West, 1982 ;Wolstrup, Jensen and Just, 1979). However, the first step of analysis, the ATP extraction, must be very reliable and simple.…”

“…Forsberg and Lam (1977) compared six different methods of extraction and obtained the best results using cold 0.6N H 2 SO 4 as the reagent which was found to extract twice as much ATP as the boiling tris buffer recently used by Nuzback et al (1983). Wallace and West (1982) Other authors (Jakubczak and Leclerc, 1981 ;Komisarczuk et al, unpublished) (1982) was used. Five ml of ice-cold 0.6N H z S0 4 were added to 5 ml of filtered rumen fluid in a stainless steel centrifuge tube.…”