Effect of two commercial yeast cultures with Saccharomyces cerevisiae on ruminal fermentation and digestion in sheep fed sugar cane tops

A feeding trial was conducted to evaluate the effect of two direct-fed microbial cultures containing Saccharomyces cerevisiae, on ruminal fermentation and digestibility of diets based on sugar cane tops. Three Suffolk ewes (30 kg BW) with ruminal cannula were used in a latin square design, where treatments were control group (CG); 3 g/day of Yea-Sacc(1026) (YS, 1 x 10(8) CFU/g) and 1 g/day of Levucell (LC, 20 x 10(9) CFU/g). The cultures were added to the rumen. Diet was based on sugar cane tops (50%), sorghum grain (21%), wheat bran (15%), molasses (12%) and urea (2%). Ruminal pH was highest (P < 0.05) in CG (6.05), and lower (P < 0.05) with YS than with LC (5.85 vs. 5.96). Total VFA concentration was greater (P < 0.05) with yeast cultures (LC, 107.6 mM; YS 105.5 mM) than in CG (97.3 mM). However, no effects were detected in VFA molar proportion, protozoa population, or total tract digestibility. In situ DM and NDF degradation was not affected by treatments. Neither direct-fed microbial culture with Saccharomyces cerevisiae improved either fermentation or digestion in sheep fed sugar cane tops. (C) 2000 Elsevier Science B.V. All rights reserved.