Effect of the Microbial Feed Additive Saccharomyces cerevisiae CNCM I-1077 on Protein and Peptide Degrading Activities of Rumen Bacteria Grown In Vitro

Abstract

We investigated the potential of the ruminant feed additive Saccharomyces cerevisiae CNCM I-1077 on protein and peptide degrading activities of the rumen bacterial species Prevotella albensis M384, Streptococcus bovis 20480, and Butyrivibrio fibrisolvens 3071 grown in vitro. Alive or heat-killed yeast cells were added to bacterial cultures in a complex casein-glucose medium. After incubation of the cultures at 39 degrees C under O(2)-free CO(2), peptidase activities were determined in the absence or in the presence of yeasts. Protease activities were detected after PAGE in gelatin-copolymerized gels. In co-incubations of bacteria and live S. cerevisiae I-1077, proteinase activities were reduced compared to the activities in the bacterial monocultures. Measurement of peptidase activities and microbial enumerations in the co-incubations suggested that live yeasts and bacteria interacted in a competitive way, leading to a decrease in peptidase activities. The mechanism responsible for such an effect could be mainly a competition for substrate utilization, but the release of small competitive peptides by the yeast cells is also likely to be implicated.

The effect of body condition score at calving and supplementation with Saccharomyces cerevisiae on milk production, metabolic status, and rumen fermentation of dairy cows in early lactation

“…The reduced rumen NH 3 -N concentration in the supplemented group may have been due to increased ammonia incorporation into microbial protein (Erasmus et al, 1992), which may be the result of enhanced microbial activity (Wiedmeier et al, 1987;Williams et al, 1991). One other possible reason for the reduced NH 3 -N in the Y group is that the LY may have reduced the activity of proteolytic rumen bacteria, as was reported in the in vitro study of Chaucheyras-Durand et al (2005). The increased protozoal population in the Y group had been previously observed in vitro (Carro et al, 1992), in sheep (Mathieu et al, 1996), in Holstein steers (Plata et al, 1994), and in Holstein dairy cows (Dolezal et al, 2005).…”

Diet digestibility and performance of dairy cows supplemented with live yeast

“…The proposed mechanism for a decrease in rumen ammonia concentration induced by yeast is related to the increased microbial growth and bacterial assimilation of nitrogen (Harrison et al, 1988). Alternatively, another explanation would be the decrease of certain bacterial peptidase activities due to the presence of yeast in the ruminal fluid (Chaucheyras-Durand et al, 2005;Putnam et al, 1997).…”

The effect of feeding live yeast cultures on ruminal pH and redox potential in dry cows as continuously measured by a new wireless device

“…by Erasmus et al (1992), Chaucheyras-Durand and Fonty (2001) or Moallem et al (2009). Based on their in vitro study, Chaucheyras-Durand et al (2005) supposed that yeast supplementation decreased the activity of ruminal proteolytic bacteria resulting in lower ammonia production. On the other hand, Erasmus et al (1992) suggested that a lower ammonia concentration found in yeast-fed cows was associated with the increased incorporation of ammonia into microbial protein.…”