Background: Thiamine supplementation in high-concentrate diets (HC) was confirmed to attenuate ruminal subacute acidosis through promoting carbohydrate metabolism, however, whether thiamine supplementation in HC impacts methane metabolism is still unclear. Therefore, in the present study, thiamine was supplemented in the high-concentrate diets to investigate its effects on ruminal methanogens and methanogenesis process. Methods: an in vitro fermentation experiment which included three treatments: control diet (CON, concentrate/forage = 4:6; DM basis), high-concentrate diet (HC, concentrate/forage = 6:4; DM basis) and high-concentrate diet supplemented with thiamine (HCT, concentrate/forage = 6:4, DM basis; thiamine supplementation content = 180 mg/kg DM) was conducted. Each treatment concluded with four repeats, with three bottles in each repeat. The in vitro fermentation was sustained for 48h each time and repeated three times. At the end of fermentation, fermentable parameters, ruminal bacteria and methanogens community were measured. Results: HC significantly decreased ruminal pH, thiamine and acetate content, while significantly increasing propionate content compared with CON (p < 0.05). Conversely, thiamine supplementation significantly increased ruminal pH, acetate while significantly decreasing propionate content compared with HC treatment (p < 0.05). No significant difference of ruminal methanogens abundances among three treatments was observed. Thiamine supplementation significantly decreased methane production compared with CON, while no significant change was found in HCT compared with HC. Conclusion: thiamine supplementation in the high-concentrate diet (HC) could efficiently reduce CH₄ emissions compared with high-forage diets while without causing ruminal metabolic disorders compared with HC treatment. This study demonstrated that supplementation of proper thiamine in concentrate diets could be an effective nutritional strategy to decrease CH₄ production in dairy cows.

中文翻译：

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高浓度饮食中补充硫胺素的瘤胃产甲烷反应。


背景：高浓度日粮（HC）中补充硫胺素已被证实可通过促进碳水化合物代谢来减轻瘤胃亚急性酸中毒，然而，高浓度日粮中补充硫胺素是否影响甲烷代谢仍不清楚。因此，本研究在高浓度日粮中添加硫胺素，探讨其对瘤胃产甲烷菌及产甲烷过程的影响。方法：体外发酵实验，包括三种处理：对照日粮（CON，浓缩物/草料= 4：6；以DM为基础）、高浓缩日粮（HC，浓缩物/草料= 6：4；以DM为基础）和高浓度日粮（HC，浓缩物/草料= 6：4；DM基础）。进行补充硫胺素的浓缩日粮（HCT，浓缩物/饲料= 6:4，以DM为基础；硫胺素补充含量= 180 mg/kg DM）。每个治疗以四次重复结束，每次重复使用三瓶。体外发酵每次持续48h，重复3次。发酵结束时，测量可发酵参数、瘤胃细菌和产甲烷菌群落。结果：与 CON 相比，HC 显着降低瘤胃 pH 值、硫胺素和乙酸含量，同时显着增加丙酸盐含量 ( p < 0.05)。相反，与 HC 处理相比，补充硫胺素显着增加瘤胃 pH 值和乙酸盐，同时显着降低丙酸盐含量 ( p < 0.05)。三种处理之间瘤胃产甲烷菌丰度没有观察到显着差异。与 CON 相比，补充硫胺素显着降低了甲烷产量，而与 HC 相比，HCT 没有发现显着变化。 结论：与高精饲料相比，在高精日粮中添加硫胺素可有效减少CH ₄排放，且与HC处理相比不会引起瘤胃代谢紊乱。这项研究表明，在浓缩日粮中补充适当的硫胺素可能是减少奶牛 CH ₄产量的有效营养策略。