| Popis: |
Summary Adenosine nucleotides (AN) (AMP, A DP and ATP) were assayed in the rumen fluid, at once, to quantify the ruminal biomass and to estimate the physiological state of the microbial populations during digestion. Several extractants were tested The most effective was DMSO, which does not inhibit enzymic transformation AMP→ADP→ATP, and allows to determine the adenylate energy charge of the ecosystem. No “dissolved” AN were found in the rumen contents. Several in vivo and in vitro experimental situations were studied; the amount of AN was comparatively quantified during digestion after the meal in holoxenic lambs, mature defaunated sheep, mature sheep with conventional flora and complex fauna, and in an artificial fermentation system (RUSITEC) alter “feeding”. The levels of AN contents in the rumen fluid are related to the complexity of the situations studied. The maximum values of AN are reached just after the meal in lambs and defaunated sheep; this is the reflection of a fast bacterial biomass production. In faunated sheep the initial decrease in AN content is in agreement with the ciliate behaviour (sequestration in plant particles). In RUSITEC the increase in AN amount after “feeding” in the liquid phase of reactors can be partly interpreted as a “redistribution” of the bacterial populations among the different compartments. These results are discussed in relation to the main fermentative parameters concurrently produced (VFA, N-NH 3 ). |
