The dairy cow’s postpartum period is characterized by dramatic physiological changes, therefore imposing severe challenges on the animal for maintaining health and milk output. The dynamics of the ruminal microbiota are also tremendous and may play a crucial role in lactation launch. We aim to investigate the potential benefits of early microbial intervention by fresh rumen microbiota transplantation (RMT) and sterile RMT in postpartum dairy cows. Twelve fistulated peak-lactation dairy cows were selected to be the donors for rumen fluid collection. Thirty postpartum cows were divided into 3 groups as the transplantation receptors respectively receiving 10 L fresh rumen fluid (FR), 10 L sterile rumen fluid (SR), or 10 L saline (CON) during 3 d after calving. Production performance, plasma indices, plasma lipidome, ruminal microbiome, and liver transcriptome were recorded. After fresh and sterile RMT, we found that the molar proportion of propionic acid was increased on d 7 in the FR and SR groups and the bacterial composition was also significantly changed when compared with the CON group. A similarity analysis showed that the similarities between the CON group and FR or SR group on d 7 were 48.40% or 47.85%, whereas the similarities between microbiota on d 7 and 21 in the FR and SR groups were 68.34% or 66.85%. Dry matter intake and feed efficiency were not affected by treatments. Plasma β-hydroxybutyrate concentration in the FR group was decreased and significantly different lipids mainly included phosphatidylcholine and lysophosphatidylcholine containing polyunsaturated fatty acids. Hepatic transcriptomics analysis indicated acute-phase response pathways were upregulated in the SR group. Our study suggests that RMT can shorten the transition process of the ruminal microbiota of postpartum dairy cows with no benefit on dry matter intake or feed efficiency. Inoculation with rumen fluid may not be a useful approach to promote the recovery of postpartum dairy cows.

中文翻译：

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反复接种瘤胃液会加速瘤胃细菌的转变，但对产后荷斯坦奶牛的生产性能没有好处

奶牛产后的生理变化非常剧烈，对奶牛的健康和产奶量提出了严峻的挑战。瘤胃微生物群的动态也很大，可能在泌乳启动中发挥至关重要的作用。我们的目的是研究通过新鲜瘤胃微生物移植 (RMT) 和无菌 RMT 进行早期微生物干预对产后奶牛的潜在益处。选择12头有瘘管的泌乳高峰奶牛作为瘤胃液采集的供体。将30头产后奶牛分为3组作为移植受体，分别在产犊后3 d内接受10 L新鲜瘤胃液（FR）、10 L无菌瘤胃液（SR）或10 L生理盐水（CON）。记录生产性能、血浆指数、血浆脂质组、瘤胃微生物组和肝脏转录组。经过新鲜无菌RMT后，我们发现与CON组相比，FR组和SR组在第7天丙酸的摩尔比例有所增加，并且细菌组成也发生了显着变化。相似性分析显示，第7天CON组与FR或SR组的相似度分别为48.40%或47.85%，而FR和SR组第7天和第21天微生物群的相似度分别为68.34%或66.85%。干物质摄入量和饲料效率不受处理的影响。 FR组血浆β-羟基丁酸浓度降低，脂质差异显着，主要为含有多不饱和脂肪酸的磷脂酰胆碱和溶血磷脂酰胆碱。肝脏转录组学分析表明 SR 组的急性期反应途径上调。我们的研究表明，RMT 可以缩短产后奶牛瘤胃微生物群的转变过程，但对干物质采食量或饲料效率没有好处。接种瘤胃液可能不是促进产后奶牛恢复的有效方法。