Comparison of two commercial yeast cultures (Saccharomyces cerevisiae) on ruminal fermentation and digestion in sheep fed on corn-stover diet

A metabolism trial was conducted to evaluate the effect of two direct-fed microbial cultures containing Saccharomyces cerevisiae on ruminal fermentation, digestibility and duodenal amino acid flow. Nine Suffolk ewes with ruminal and duodenal cannula (29 kg BW) were assigned to a completely randomized design, where treatments were: (1) control group (CG); (2) 3 g/day of Yea-Sacc(1026) (YS, 1x10(8) CFU/g); and (3) 1 g/day of Levucell (LC, 20x10(9) CFU/g). The diet consisted of corn stover (66.5%), sorghum grain (23.5%), molasses (8.6%) and urea (1.4%). Ruminal pH was lower (p<.01) with yeast culture (CG 6.81(a), YS 6.51(b), LC 6.61(b)). No effects were detected in VFA concentration, molar proportion, ammonia-N, and protozoa population. Total tract digestibility of DM, OM, NDE and ADF were not affected by treatments. Duodenal amino acid flow was not affected by the inclusion of yeast cultures. None of the direct-fed microbial cultures with Saccharomyces cerevisiae improved either fermentation, digestion or amino acid flow to the duodenum in sheep fed on corn-stover diet. (C) 1998 Elsevier Science B.V. All rights reserved.