Influence of Rhaponticum carthamoides Wild on the growth of ruminal bacteria in vitro and on fermentation in an artificial rumen (Rusitec).

The fermentation of a basal diet composed of hay and barley (80:20%) was compared with fermentation of three rations in which 5 and 10% of hay and 10% of basal diet were replaced with the above-ground part of Rhaponticum carthamoides Wild in an artificial rumen (Rusitec). Results of 14 days experiments indicated that the digestibility of dry matter, organic matter, detergent fibre, production of CO2 and methane, NH3-N in effluent and total and individual VFA (mmol/day) were not affected in the process of fermentation of experimental diets in comparison with the basal diet. Addition of Rhaponticum carthamoides did not modify the production, utilization and recovery of metabolic hydrogen, glucose utilization, ATP production, YATP and effectiveness of microbial biomass synthesis expressed in g of microbial N/kg of organic fermented biomass. Water extracts of Rhaponticum carthamoides had no influence on growth parameters of a mixed culture of rumen bacteria. Overall results of this experiment indicated that the above-ground part of Rhaponticum carthomoides fully replaced the 5 and 10% portions of hay or 10% portion of the whole diet.