Effect of Saccharomyces cerevisiae Supplementation to Paddy Straw Based Substrate on in Vitro Rumen Fermentation Parameters

The Saccharomyces cerevisiae was supplemented to the substrate containing paddy straw (60%) and concentrate mixture (40%) at various doses viz., 0.0 (control), 0.5 × 10⁶, 0.5 × 10⁷ and 0.5 × 10⁸ CFU. The in vitro true dry matter degradability, total gas production, volatile fatty acid production and microbial population increased proportionally to the dose of S. cerevisiae. However, methane production was not affected significantly. The ruminal pH and ammonia nitrogen levels decreased (P<0.01) in yeast supplemented groups. Increasing the level of S. cerevisiae supplementation enhanced (P<0.01) bacteria and protozoa population. These results revealed that the positive effects on in vitro ruminal fermentation were dose dependent.