Differing effects of 2 active dried yeast (Saccharomyces cerevisiae) strains on ruminal acidosis and methane production in nonlactating dairy cows

Abstract

Fifteen ruminally cannulated, nonlactating Holstein cows were used to measure the effects of 2 strains of Saccharomyces cerevisiae, fed as active dried yeasts, on ruminal pH and fermentation and enteric methane (CH(4)) emissions. Nonlactating cows were blocked by total duration (h) that their ruminal pH was below 5.8 during a 6-d pre-experimental period. Within each block, cows were randomly assigned to control (no yeast), yeast strain 1 (Levucell SC), or yeast strain 2 (a novel strain selected for enhanced in vitro fiber degradation), with both strains (Lallemand Animal Nutrition, Montréal, QC, Canada) providing 1 × 10(10) cfu/head per day. Cows were fed once daily a total mixed ration consisting of a 50:50 forage to concentrate ratio (dry matter basis). The yeast strains were dosed via the rumen cannula daily at the time of feeding. During the 35-d experiment, ruminal pH was measured continuously for 7 d (d 22 to 28) by using an indwelling system, and CH(4) gas was measured for 4 d (d 32 to 35) using the sulfur hexafluoride tracer gas technique (with halters and yokes). Rumen contents were sampled on 2 d (d 22 and 26) at 0, 3, and 6h after feeding. Dry matter intake, body weight, and apparent total-tract digestibility of nutrients were not affected by yeast feeding. Strain 2 decreased the average daily minimum (5.35 vs. 5.65 or 5.66), mean (5.98 vs. 6.24 or 6.34), and maximum ruminal pH (6.71 vs. 6.86 or 6.86), and prolonged the time that ruminal pH was below 5.8 (7.5 vs. 3.3 or 1.0 h/d) compared with the control or strain 1, respectively. The molar percentage of acetate was lower and that of propionate was greater in the ruminal fluid of cows receiving strain 2 compared with cows receiving no yeast or strain 1. Enteric CH(4) production adjusted for intake of dry matter or gross energy, however, did not differ between either yeast strain compared with the control but it tended to be reduced by 10% when strain 2 was compared with strain 1. The study shows that different strains of S. cerevisiae fed as active dried yeasts vary in their ability to modify the rumen fermentative pattern in nonlactating dairy cows. Because strain 2 tended (when compared with strain 1) to lower CH(4) emissions but increase the risk of acidosis, it may be prudent to further evaluate this strain in cattle fed high-forage diets, for which the risk of acidosis is low but CH(4) emissions are high.

Modification of the feeding behavior of dairy cows through live yeast supplementation

“…Similar to the temperature results, Thrune et al (2009) reported greater mean ruminal pH and less time spent under a pH threshold of 5.6 with live yeast supplementation. Similarly, Chung et al (2011) reported that time spent below pH of 5.8 was numerically reduced using the same live yeast strain as used in the present study. Saccharomyces cerevisiae has been shown to create a more anaerobic environment through oxygen scavenging (Newbold et al, 1996), as well as provide growth factors (including organic acids, B vitamins, and AA) that stimulate microbial growth, particularly lactate utilizers (Chaucheyras-Durand et al, 2008).…”

<italic>Saccharomyces cerevisiae</italic> Live Cells Decreased <italic>In vitro</italic> Methane Production in Intestinal Content of Pigs

“…This result is in agreement with a previous study that Saccharomyces cerevisiae reduces ruminal CH 4 production (Lynch and Martin, 2002), but others found no effect (Lila et al, 2004) or an increase (Martin et al, 1989) in batch cultures with mixed rumen microflora. The discrepancies among studies could be associated with the characteristics of the strain (Chuang et al, 2011), diet composition (Sullivan and Martin, 1999) and dose (Lila et al, 2006). …”

Invited review: Large-scale indirect measurements for enteric methane emissions in dairy cattle: A review of proxies and their potential for use in management and breeding decisions

“…Although this relationship holds in some studies (e.g., Chung et al, 2011;Van Zijderveld et al, 2010), treatment effects on CH 4 emissions and VFA proportions did not correspond in about half of the studies (e.g., Beauchemin et al, 2009;Brask et al, 2015;Supplementary Table S1; https://doi.org/10.3168/jds.2016-12030). Overall, the relations between CH 4 emission and both VFA and pH are variable in the literature and not as straightforward as expected from theory.…”