Rumen fermentation and acetogen population changes in response to an exogenous acetogen TWA4 strain and Saccharomyces cerevisiae fermentation product

Abstract

Abstract:The presence of yeast cells could stimulate hydrogen utilization of acetogens and enhance acetogenesis. To understand the roles of acetogens in rumen fermentation, an in vitro rumen fermentation experiment was conducted with addition of acetogen strain (TWA4) and/or Saccharomyces cerevisiae fermentation product (XP). A 2×2 factorial design with two levels of TWA4 (0 or 2×10 7 cells/ml) and XP (0 or 2 g/L) was performed. Volatile fatty acids (VFAs) were increased (P<0.05) in XP and TWA4XP, while methane was increased only in TWA4XP (P<0.05). The increase rate of microorganisms with formyltetrahydrofolate synthetase, especially acetogens, was higher than that of methanogens under all treatments. Lachnospiraceae was predominant in all acetogen communities, but without close acetyl-CoA synthase (ACS) amino acid sequences from cultured isolates. Low-Acetitomaculum ruminis-like ACS was predominant in all acetogen communities, while four unique phylotypes in XP treatment were all amino acid identified low-Eubacterium limosum-like acetogens. It differs to XP treatment that more low-A. ruminis-like and less low-E. limosum-like sequences were identified in TWA4 and TWA4XP treatments. Enhancing acetogenesis by supplementation with an acetogen strain and/or yeast cells may be an approach to mitigate methane, by targeting proper acetogens such as uncultured low-E. limosum-like acetogens.

Effects of reductive acetogenic bacteria and lauric acid on in vivo ruminal fermentation, microbial populations, and methane mitigation in Hanwoo steers in South Korea

“…LA-supplemented and control groups in the study by Dohme et al (2001) had comparable concentrations during rumen fermentation using the rumen simulation technique. In addition, VFA concentrations were not affected by exogenous acetogens (Yang et al, 2015) or by 6 reductive acetogenic bacteria from a variety of ruminal and nonruminal environments (Lopez et al, 1999) when added in in vitro rumen fermentation, which corroborates the findings of this study when acetogen was independently provided to the animals. Meanwhile, the H-NMR spectroscopy results revealed no significant difference among treatments and no correlation between the LA and Con groups.…”

Microbiological Surveillance of Biogas Plants: Targeting Acetogenic Community

“…The species Acetitomaculum ruminis was only observed (RA >3%) in the manure-supplemented reactors C3-K1/2 and C4-VS1/2. It is a known acetogen present in the rumen and performs reductive acetogenesis (Greening and Leedle, 1989; Le Van et al, 1998;Yang et al, 2015). An increase in RA of this species and decrease in RA of Cloacimonetes_HGW3 was observed prior to VFA accumulation (~day 175-217) in reactor C4-VS2, indicating a role in acetogenesis and syntrophic acid oxidation, respectively.…”

Effects of a Saccharomyces cerevisiae fermentation product on liver abscesses, fecal microbiome, and resistome in feedlot cattle raised without antibiotics

“…Saccharomyces cerevisiae fermentation products (SCFP) have also been evaluated for use as feed additives in dairy and beef production. Some studies have shown that SCFP can positively impact gastrointestinal health for cattle exposed to high-concentrate diets, by providing components including amino acids, peptides, organic acids, and oligosaccharides 18–20 . In some studies, inclusion of SCFP in cattle diets improved performance characteristics, including increased milk production 21 , increased volatile fatty acid concentration, decreased rumen pH 22 , efficient feed conversion, and improved carcass traits 23 .…”