The Effects of a Probiotic Yeast on the Bacterial Diversity and Population Structure in the Rumen of Cattle

Abstract

It has been suggested that the ability of live yeast to improve milk yield and weight gain in cattle is because the yeast stimulates bacterial activity within the rumen. However it remains unclear if this is a general stimulation of all species or a specific stimulation of certain species. Here we characterised the change in the bacterial population within the rumen of cattle fed supplemental live yeast. Three cannulated lactating cows received a daily ration (24 kg/d) of corn silage (61% of DM), concentrates (30% of DM), dehydrated alfalfa (9% of DM) and a minerals and vitamins mix (1% of DM). The effect of yeast (BIOSAF SC 47, Lesaffre Feed Additives, France; 0.5 or 5 g/d) was compared to a control (no additive) in a 3×3 Latin square design. The variation in the rumen bacterial community between treatments was assessed using Serial Analysis of V1 Ribosomal Sequence Tag (SARST-V1) and 454 pyrosequencing based on analysis of the 16S rRNA gene. Compared to the control diet supplementation of probiotic yeast maintained a healthy fermentation in the rumen of lactating cattle (higher VFA concentration [high yeast dose only], higher rumen pH, and lower Eh and lactate). These improvements were accompanied with a shift in the main fibrolytic group (Fibrobacter and Ruminococcus) and lactate utilising bacteria (Megasphaera and Selenomonas). In addition we have shown that the analysis of short V1 region of 16s rRNA gene (50–60 bp) could give as much phylogenetic information as a longer read (454 pyrosequencing of 250 bp). This study also highlights the difficulty of drawing conclusions on composition and diversity of complex microbiota because of the variation caused by the use of different methods (sequencing technology and/or analysis).

The Effect of Live Yeast Supplementation on Beef Cattle Performance: A Systematic Review and Meta-Analysis

“…This may be due to an increase in lactate-utilizing bacteria, Selenomonas ruminantium and Megasphaera elsdenii. These bacteria convert lactate to propionate (Lettat, Martin, Berger, & Nozière, 2012;Silberberg et al, 2013) and have their growth stimulated by the supplementation of yeast (Pinloche et al, 2013).…”

“…This yeast can stimulate microbial growth-mainly lactic acid-utilizing bacteria-and then reduce the likelihood of acidosis (Lila et al, 2004;Pinloche et al, 2013;Ding et al, 2014). Moreover, S. cerevisiae decreases the redox potential of the rumen and promotes a more favorable environment for the development of microorganisms-mainly cellulose consumers-which maximize the fibre degradation rates (McAllister et al, 2011).…”

Effects ofSaccharomyces Cerevisiaeat Direct Addition or Pre-incubation onin VitroGas Production Kinetics and Degradability of Four Fibrous Feeds

“…S. cerevisiae have the ability to increase dry matter (DM) and neutral detergent fibre (NDF) digestion (Carro et al, 1992), increase initial rates of fibre digestion (Williams et al, 1991). Numerous studies (Kumar et al, 2013;Pinloche et al, 2013) documented positive effects of yeast, not only on the rumen environment, but also on the improvement of microbial activities. S. cerevisiae supplementation leads to increase in the number of total anaerobic and cellulolytic bacteria (Newbold et al, 1996;Jouany, 2001).…”

Modulation of the rumen microbiome

“…In addition, a further 11 registered products are available that are exclusively based on the yeast Saccharomyces cerevisiae. While the survival and proliferation of these organisms in the rumen and the effect of these probiotic bacteria on rumen digestive processes has been largely under-represented in the scientific literature, the probiotic effects of yeasts (S. cerevisiae) has been more extensively assessed 33,34 . Results can be highly variable between studies, however several investigations have established that the provision of these commercially available probiotics is most useful when applied to young ruminants to accelerate the establishment of a healthy gastrointestinal microflora 35,36 .…”