Influence of Yeast Products on Rumen Microorganisms,In vitroDegradation and Fermentation of a Diet for Steers

Cobos, M.A., Valencia, L.H., Pinos-Rodríguez, J.M., González-Muñoz, S.S., Ramírez, J. and Hernández, D. 2010. Influence of yeast products on rumen microorganisms, in vitro degradation and fermentation of a diet for steers. J. Appl. Anim. Res., 37: 129–133. The objectives of this study were to examine the influence of products of Saccharomyces cerevisiae Yea-Sacc (YS), Diamond VXP (DV) and Procreatin 7 (P7) on the rumen microorganisms, in vitro dry matter degradation (IVDMD) and fermentation of a diet with 818 g/kg of concentrate for steers. None of the yeast products modified the IVDMD of the diet and pH of fluids incubated. At some incubation times, DV and P7 increased (P<0.05) protozoa and cellulolytic bacteria versus control and YS. At 24 h, lactic acid concentrations were reduced with all of the yeast products. Ammonia nitrogen concentrations were lower with DV and P7 than YS and control. At 24 h, acetate: propionate ratio was increased by all yeast products, Rumen microorganism counts were increased by DV and P7 and fermentation efficiency by YS but none improved IVDMD.