Effects of hydrolysed yeasts on ruminal fermentation in the rumen simulation technique (Rusitec)

Abstract

ABSTRACT:The objective of the present study was to investigate the effects of three different hydrolysed yeast products derived from Saccharomyces cerevisiae [hydrolysed whole yeast (HWY), less hydrolysed whole yeast (LHWY), and yeast cell wall (YCW)] on microbial fermentation characteristics using the rumen simulation technique (Rusitec) with three consecutive experiments. The Rusitec system consisted of six fermentation vessels. Each vessel received 5 g chopped meadow hay and 4 g concentrate (as-fed basis) daily for up to 22 days. Yeast products were added to the fermentation vessels at a concentration of 0.25 or 0.75 g/day. In most cases, ruminal microbial activity was stimulated by HWY and YCW, particularly at the 0.75 g/day level. HWY resulted in a decrease (P < 0.05) in ruminal pH and an increase (P < 0.05) in total short-chain fatty acid (SCFA), acetate, propionate and methane productions, and an increase in NH 3 -N concentration when compared with the control values. Ruminal pH was not altered, but total SCFA, acetate, propionate, butyrate, and methane productions as well as NH 3 -N concentration increased (P < 0.05) in response to YCW treatment. Digestibility of organic matter was not significantly affected by either HWY or YCW. The effects of LHWY on ruminal fermentation characteristics were negligible. These results indicate that degree of hydrolysation (low or high) and composition of yeasts (whole cell or cell wall) have remarkable effects on ruminal microbial activity in the Rusitec system.

Influence of increasing doses of a yeast hydrolyzate obtained from sugarcane processing on in vitro rumen fermentation of two different diets and bacterial diversity in batch cultures and Rusitec fermenters

“…Supplementation with YHS shifted VFA profile from acetate to propionate, reducing the acetate:propionate ratio. Similar results have been recently reported by supplementing different YH to batch cultures (Kettunen et al, 2016) and Rusitec fermenters (Oeztuerk et al, 2016). The trend to reduced CH 4 production observed in YHS-fermenters in our study is consistent with the increased propionate proportions, as production of propionate serves as a competitive pathway for hydrogen.…”

“…Rossi et al (2004) reported that the peptidic fractions of S. cerevisiae stimulated the growth of Megasphaera ehdenii, the major lactate utilizer in the rumen, and Meissner et al (2014) observed that a S. cerevisiae YH increased the growth of Megasphaera ehdenii and enhanced the in vitro ruminal fermentation of a high-fermentable substrate. More recently, Kettunen et al (2016) and Oeztuerk et al (2016) have reported the efficacy of a patented S. cerevisiae YH product to stimulate the in vitro fermentation of different diets in batch cultures and Rusitec fermenters, respectively.…”

Inclusion of live yeast and mannan-oligosaccharides in high grain-based diets for sheep: Ruminal parameters, inflammatory response and rumen morphology

“…Similar results were reported by Li et al [ 8 ], who also found increased production of SCFA using increasing levels of oligosaccharides (0.2 to 0.8%) in the basal diet of sheep. According to Pinloche et al [ 25 ], a rise in SCFA concentration may be related to increased metabolic activity by ruminal microorganisms, and stimulation of microbial growth, which is beneficial for the maintenance and production of the ruminant [ 26 ]. However, the accumulation and dissociation of SCFA in ruminal fluid lowers the pH, as observed in this experiment, which may cause morphological and histological changes in the ruminal papillae and thus impair the barrier function of the ruminal epithelium [ 27 , 28 , 29 ].…”

Effect of post-fermentative yeast biomass as a substitute for soybean meal on feed utilization and rumen ecology in Thai native beef cattle

“…Total VFA at 0 and 4 h post feeding ranged from 118.4 to 118.6 mmol/l and from 118.5 to 118.7 mmol/l, respectively. However, some studies revealed that supplementation with yeast hydrolysate shifted the VFA profile from C2 to C3 and reduced the C2:C3 ratio in batch cultures (Kettunen et al, 2016) and Rusitec fermenters (Oeztuerk et al, 2016;Díaz et al, 2017).…”