Effect of rhubarb (Rheum spp.) root on in vitro and in vivo ruminal methane production and a bacterial community analysis based on 16S rRNA sequence

Abstract

The objective of this study was to evaluate the anti-methanogenic effect of rhubarb (Rheum spp.) on in vitro, in vivo, and bacterial community composition using Quantitative Insights into Microbial Ecology sequencing. Rhubarb root powder was tested at different concentrations (0, 0.33, 0.67, and 1.33 g/L) in vitro, and all incubations were carried out in triplicate two runs on separate days. Concentrations of 0.67 and 1.33 g/L rhubarb significantly (P < 0.05) reduced methane production and the acetate : propionate ratio compared with those of the Control, without adverse effects on total volatile fatty acids and total gas production. In the second in vivo trial, four Hanwoo (Korean native) steers (live bodyweight, 556 ± 46 kg) with a ruminal cannula were housed individually in metabolic stalls and fed a basal diet twice daily in equal amounts at 0900 hours and 2100 hours. The before rhubarb treatment (before treatment) duration was 24 days for all steers; 14 days were used for diet adaptation and 10 days were used for gas samples collected 1, 2, and 3 h after the morning feeding on Days 3, 5, 7, and 9. We used three syringe needles passed through the ruminal cannula stopper at different time points as a simple and rapid method to sample rumen gas. Thereafter, three mesh bags containing 30 g of sliced rhubarb root each were placed at different depths in the rumen of each steer for 14 days (after treatment), and gas samples were collected on Days 4, 7, 10, 12, and 13. The results showed a significant (P < 0.05) decrease in methane concentration from the rhubarb-treated steers and provide the evidence that this method would be useful for in vivo screening of anti-methanogenic feed additives or plant material. Furthermore, 16s RNA sequencing after treatment showed increases in the numbers of Prevotella, and Lactobacillus, but decreases in Methanobrevibacter. In conclusion, rhubarb had an anti-methanogenic effect in vitro and in vivo, and the increase in the number of Prevotella shifted ruminal fermentation towards propionate production.

Investigation and manipulation of metabolically active methanogen community composition during rumen development in black goats

“…In contrast, Kim et al . 26 found no significant difference in the relative abundance of Methanobrevibacter between the samples before and after the inclusion of rhubarb in the rumen of steers. This inconsistency might be ascribed to the differences between the species of rhubarb and/or the hosts used in the two studies and needs further investigations to be explained.…”

“…is commonly used as a herb in traditional Chinese medicine that contains anti-microbial ingredients, such as such as emodin, aloe-emodin and rhein 25 , and may be a potential CH 4 mitigation agent. Previous in vitro and in vivo investigations found that rhubarb could inhibit ruminal methanognesis, and alter rumen fermentation through propionate production 26 , 27 . However, these studies were aimed at regulating rumen fermentation in mature ruminants.…”

Changes in Metabolically Active Bacterial Community during Rumen Development, and Their Alteration by Rhubarb Root Powder Revealed by 16S rRNA Amplicon Sequencing

“…Effects of rhubarb treatment on rumen fermentation have been examined in a few investigations in vitro and in vivo , indicating that rhubarb might manipulate rumen fermentation by reducing methane production and the acetate: propionate ratio without negative side effects, such as suppressing feed intake or digestibility (Bodas et al, 2008 ; García-González et al, 2010 , 2012 ). Recently, it was found that the relative abundances of Prevotella and Lactobacillus were improved after the treatment of rhubarb (Kim et al, 2016 ). By contrast, result of the present study shows no difference in the abundances of Lactobacillus between the control diet and the rhubarb treatment, and there were only numerical increases in the proportions of Prevotella in rhubarb treatment compared to the control.…”

“…is a commonly used herb in traditional Chinese medicine to cure indigestion, constipation, and other diseases since ancient times, and it has been characterized with antimicrobial and antitumor properties in previous research (Kang et al, 2008 ; Kosikowska et al, 2010 ). Previous in vitro and in vivo studies reported that rhubarb could modify rumen fermentation by lowering methane production and the acetate: propionate ratio without inhibiting feed intake or the degradation of substrates (Bodas et al, 2008 ; García-González et al, 2010 , 2012 ; Kim et al, 2016 ). As all these investigations were focused on mature ruminants and rumen fermentation, it would be promising to explore the effects of rhubarb as feed additive in shaping the rumen bacteria community in early life during rumen development.…”

Anti-methanogenic effect of rhubarb (Rheum spp.) – An in silico docking studies on methyl-coenzyme M reductase (MCR)

“…According to our previous study, rhubarb decreased ruminal methane emission in vivo by reducing Methano brevibacter population but the mode of mechanism not reported (Kim et al, 2016) and in another study, the chemical composition (35 compounds) of rhubarb was reported (Arokiyaraj et al, 2017). To extend our research in methane mitigation strategies, we made a new approach to find the interaction between the phytochemical compounds and MCR for its anti-methanogenic mechanism using molecular docking techniques.…”