Cassava pulp can be nutritionally improved by yeast and various crude protein levels fed to cattle

Context Dietary supplementation especially feed residues improve by yeast affected rumen fermentation. Aims The aim of the present experiment was to determine the nutritive value, fermentation efficiency and rumen ecology of yeast-fermented cassava pulp, under the use of two levels of protein in concentrate mixtures, in beef cattle. Methods Four beef cattle, 2–3 years of age, were randomly assigned to the following treatments according to a 2 × 2 factorial arrangement in a 4 × 4 Latin square design: cassava pulp fermented either with baker’s yeast or LDD 6 (Factor A), with 16% or 18% CP in concentrate (Factor B). Key results CP digestibility and blood urea nitrogen were higher in animals fed both baker’s yeast-fermented and LDD 6-fermented cassava pulp with 18% CP than in those fed baker’s yeast-fermented cassava pulp with 16% CP and LDD 6-fermented cassava pulp with 16% CP. The highest total volatile fatty acid (TVFA) and butyrate (C4) concentrations were in animals fed baker’s yeast-fermented cassava pulp with 16% CP. Moreover, CH4 production was at its lowest when animals were fed with baker’s yeast-fermented cassava pulp together with a concentrate with 16% CP. Animal’s fed baker’s yeast-fermented and LDD 6-fermented cassava pulp with 18% CP had higher concentrations of purine derivatives, higher microbial nitrogen supply and efficiency of microbial protein synthesis than did those fed either baker’s yeast-fermented or LDD 6-fermented cassava pulp with 16% CP. In addition, protozoa population in animals fed baker’s yeast-fermented cassava pulp was lower than in those fed LDD 6-fermented cassava pulp, and baker’s yeast-fermented cassava pulp with 16% CP had the lowest protozoa population. However, F. succinogenes was the highest in animals fed yeast-fermented and LDD 6-fermented cassava pulp with 18% CP. Conclusions It is concluded that yeast-fermented cassava pulp can be nutritionally improved, especially when used in combination with a concentrate of 16% CP to achieve the highest level of TVFA and C3 and to reduce rumen protozoal population and CH4 production. Implications The present study suggests that feeding animals with yeast-fermented cassava pulp with a concentrate of 16% CP could improve feed quality and, hence, beef animal performance in Thailand.