Feed ration fermentation by means of the rumen contents of fallow-deer and ram in an artifical rumen (RUSITEC)

An experiment was conducted in the RUSITEC (Rumen Simulation Technique) artificial rumen. The inoculum - solid rumen contents with the rumen fluid od fallow-deer (V1, V2) and ram (V3, V4) was put to four fermentation vessels (V1, V2, V3, V4). A basal feed ration consisting of hay and barley meal (80:20 per cent) was subjected to fermentation. An addition of 200 mg urea dissolved in 1 l McDougall buffer provided for the 13 per cent content of crude protein (CP) in the feed ration in each fermentation vessel. The experiment lasted twelve days: so called steady state period took the first six days, in the course of which the fermentation conditions in the RUSITEC artificial rumen got stabilized. The feed ration fermentation was more effective in the vessels V3 and V4, containing the ram inoculum. This was manifested by the higher dry matter digestibility of feed ration, higher production of acetic acid, n-butyric and isovaleric acids, higher acetate:propionate ratio, but also by the insignificantly higher production of CO2 and methane, glucose utilization, adenosine triphosphate production, organic matter fermentation and effectiveness of microbial matter synthesis (YATP). There was a significant decrease in the following parameters: energy yield (E) of volatile fatty acids (VFA), proportion of VFA energy with respect to the fermented hexose energy (E1) and the proportion of energy in bacterial cells with respect to the fermented hexose energy (E3), and an increase in the proportion of methane energy with respect to the fermented hexose energy (E2), in the course of the feed ration fermentation in V3 and V4. The inoculum prepared from the ram rumen contents had better effects also in the process of proteosynthesis if the course of fermentations is evaluated. These better effects resulted in the higher production of microbial protein (PM), higher protein conversion ratio (R), and especially higher effectiveness of microbial proteosynthesis (E).