Effect of addition cattle feed supplement on in vitro fermentation, synthesis of microbial biomass, and methane production of rice straw fermentation basal diets

Abstract

The objective of this study was to evaluate the influence of supplementation of cattle feed supplement (CFS) and concentrate in ruminant diets based on rice straw fermented (R) on in vitro rumen fermentation, microbial biomass synthesis, and enteric methane production. Five experimental diets were evaluated, consist of R = rice straw fermented 100%, RS = R + CFS 10%, RSC1, 2 and 3 = RS + Concentrate levels 10, 20 and 30 (%DM). Supplementation of CFS increased the gas production (P < 0.05) and highest in treatments RSC1 and 2 (44.09 and 44.87 ml/g substrate, respectively) and was decreased proportions of methane by inhibition rate until 49.80%. Ruminal protozoa population increased by CFS dan concentrate supplementation (P<0,05) and was dominated (>80%) of Entodinium genus. The treatments RS dan RSC1 promoted greater (P < 0.01) microbial biomass synthesis (386.32 and 312.39 mg/g substrate, respectively). In conclusion, the supplementation of CFS and concentrate in ruminant diets based on rice straw fermented can promote a greater synthesis of microbial biomass and mitigation of methane production.