Effects of Thymol Supplementation on Goat Rumen Fermentation and Rumen Microbiota In Vitro

Abstract

This study was performed to explore the predominant responses of rumen microbiota with thymol supplementation as well as effective dose of thymol on rumen fermentation. Thymol at different concentrations, i.e., 0, 100 mg/L, 200 mg/L, and 400 mg/L (four groups × five replications) was applied for 24 h of fermentation in a rumen fluid incubation system. Illumina MiSeq sequencing was applied to investigate the ruminal microbes in addition to the examination of rumen fermentation. Thymol doses reached 200 mg/L and significantly decreased (p < 0.05) total gas production (TGP) and methane production; the production of total volatile fatty acids (VFA), propionate, and ammonia nitrogen, and the digestibility of dry matter and organic matter were apparently decreased (p < 0.05) when the thymol dose reached 400 mg/L. A thymol dose of 200 mg/L significantly affected (p < 0.05) the relative abundance of 14 genera of bacteria, three species of archaea, and two genera of protozoa. Network analysis showed that bacteria, archaea, and protozoa significantly correlated with methane production and VFA production. This study indicates an optimal dose of thymol at 200 mg/L to facilitate rumen fermentation, the critical roles of bacteria in rumen fermentation, and their interactions with the archaea and protozoa.

Specific inhibition of Streptococcus bovis by endolysin LyJH307 supplementation shifts the rumen microbiota and metabolic pathways related to carbohydrate metabolism

“…Shen, Liu, Yu (39) reported that monensin and nisin supplementation decreased the absolute abundance of total bacteria and overall rumen fermentation (gas and VFA production) with a concomitant change in the major rumen microbiota. The supplementation of plant secondary metabolites such as thymol and oregano oil has recently shown to change the major microbiota with a concomitant reduction in feed digestion and rumen fermentation [38,40]. In the present study, endolysin LyJH307 did not affect the absolute abundance of total bacteria, ciliate protozoa (Table 3) and major microbiota from phylum to genus levels (having relative proportions > 1%) ( Figure 4).…”

Dose-response effects of the Savory (Satureja khuzistanica) essential oil and extract on rumen fermentation characteristics, microbial protein synthesis and methane production in vitro

“…The results of IVTDMD and IVTOMD revealed that EO has a depressive effect on the rumen microbial activity and in consequence on ruminal digestibility at 450 and 600 mg/L levels. Earlier studies have shown that essential oils have a typically dose-dependent effect on rumen fermentation with a specific selective effect at low and moderate, and a general inhibitory effect at high doses that generally varies depending on the type of the essential oil (Hart et al, 2008;Yadeghari et al, 2015;Yu et al, 2020). In this connection, Benchaar et al (2007) found that carvacrol reduces ruminal digestibility at doses higher than 400 mg/L in vitro.…”

“…Among a vast array of phytochemicals tested in vitro, including essential oils, plant extracts or their individual bioactive compounds, many of them have reduced ruminal methane production (El-Zaiat and Abdalla, 2019;Joch et al, 2019;Yu et al, 2020). However, it is important to notice that in many cases, methane inhibition by phytochemicals has been accompanied with a concomitant decrease in ruminal DM and OM digestibility (Oskoueian et al, 2013;Joch et al, 2019;Garcia et al, 2020).…”

Identification of Micro-Organisms that Tolerant to Anti-Nutritional Factors in the Rumen of Camel

“…Pyramidobacter was found in nonextracted acacia only. Fretibacterium has the adaptability to phenolic compounds that might explain the prevalence of this genus in non-extracted acacia (Evans and Martin, 2000;Yu et al, 2020). Additionally, genus Pyramidobacter detoxifies toxic compounds found in many plant species including acacia.…”