This study aimed to investigate the effect of resveratrol on methane production, rumen fermentation and microbial composition under high‐concentrate (HC) and high‐forage (HF) diets using the in vitro fermentation system. A total of 25 mg of resveratrol was supplemented into 300 mg of either HC or HF diet. Methane production, total volatile fatty acid (VFA) concentration, molar proportion of VFA, metabolites of resveratrol and prokaryotic community composition were measured after 12 and 24 h of in vitro fermentation. Resveratrol reduced methane production (ml per mg of dry matter degraded) by 41% and 60% under both HC and HF diets (P < 0.001), respectively, and this result could be associated with the lower abundance of Methanobrevibacter (P < 0.001) in response to resveratrol. The molar proportion of propionate was significantly higher in the resveratrol group only under the HC diet (P = 0.045). The relative abundance of 10 bacterial genera was affected by the three‐way interaction of treatment, diet and time (P < 0.05). Resveratrol was partly converted to dihydroresveratrol after 24 h of fermentation, and its degradation could be associated with microbes belonging to the order Coriobacteriales. Our results suggest that multiple factors (e.g. diet and time) should be considered in animal experiments to test the effect of polyphenol or other plant extracts on rumen fermentation, methane emission and microbial composition.

中文翻译：

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白藜芦醇以时间和饮食特异性方式影响体外瘤胃发酵，甲烷生成和原核生物群落组成。

这项研究旨在研究白藜芦醇对使用体外发酵系统在高浓度（HC）和高饲草（HF）日粮下甲烷产生，瘤胃发酵和微生物组成的影响。在300毫克的HC或HF饮食中总共补充了25毫克白藜芦醇。在体外发酵12和24小时后，测量甲烷的产生，总挥发性脂肪酸（VFA）的浓度，VFA的摩尔比，白藜芦醇的代谢产物和原核生物群落组成。在HC和HF饮食下，白藜芦醇可使甲烷生成量（每毫克降解的干物质中的毫升数）分别减少41％和60％（P  <0.001），并且该结果可能与甲基短杆菌含量较低有关（P  <0.001）对白藜芦醇的反应。仅在HC饮食下，白藜芦醇组中丙酸酯的摩尔比例显着更高（P  = 0.045）。10种细菌的相对丰度受治疗，饮食和时间的三者相互作用的影响（P  <0.05）。发酵24小时后，白藜芦醇部分转化为二氢白藜芦醇，其降解可能与属于Coriobacteriales的微生物有关。我们的结果表明，在动物实验中应考虑多种因素（例如饮食和时间），以测试多酚或其他植物提取物对瘤胃发酵，甲烷排放和微生物组成的影响。