Subclinical infection with bovine leukemia virus (BLV) in cows can cause economic losses in milk and meat production in many countries, as BLV-related negative effects. The volatile fatty acids (VFAs) and microbiota present in the digestive tracts of cows can contribute to cow health. Here, we exploratorily investigated the VFAs and microbiota in the rumen and gut with respect to subclinical BLV infection using cows housed at a single farm. We analyzed a herd of 38 cows kept at one farm, which included 15 uninfected and 23 BLV-infected cows. First, the analysis of the VFAs in the rumen, gut, and blood revealed an absence of statistically significant differences between the uninfected and BLV-infected groups. Thus, BLV infection did not cause major changes in VFA levels in all tested specimens. Next, we analyzed the rumen and gut microbiota. The analysis of the microbial diversity revealed a modest difference between the uninfected and BLV-infected groups in the gut; by contrast, no differences were observed in the rumen. In addition, the investigation of the bacteria that were predominant in the uninfected and BLV-infected groups via a differential abundance analysis showed that no significant bacteria were present in either of the microbiota. Thus, BLV infection possibly affected the gut microbiota to a small extent. Moreover, bacterial associations were compared between the uninfected and BLV-infected groups. The results of this analysis suggested that BLV infection affected the equilibrium of the bacterial associations in both microbiota, which might be related to the BLV-related negative effects. Thus, BLV infection may negatively affect the equilibrium of bacterial associations in both microbiota. Subclinical BLV infection is likely to affect the rumen and gut microbiota, which may partly explain the BLV-related negative effects.

中文翻译：

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单一农场奶牛挥发性脂肪酸和瘤胃和肠道微生物群与牛白血病病毒亚临床感染的探索性研究

奶牛亚临床感染牛白血病病毒 (BLV) 可能会造成许多国家牛奶和肉类生产的经济损失，这是与 BLV 相关的负面影响。奶牛消化道中存在的挥发性脂肪酸 (VFA) 和微生物群有助于奶牛健康。在这里，我们使用单个农场饲养的奶牛，探索性地研究了瘤胃和肠道中与亚临床 BLV 感染相关的 VFA 和微生物群。我们分析了一个农场饲养的 38 头牛群，其中包括 15 头未感染 BLV 的牛和 23 头感染 BLV 的牛。首先，对瘤胃、肠道和血液中 VFA 的分析表明，未感染组和 BLV 感染组之间不存在统计学上的显着差异。因此，BLV 感染并未导致所有测试样本中 VFA 水平发生重大变化。接下来，我们分析了瘤胃和肠道微生物群。对微生物多样性的分析显示，肠道中未感染组和 BLV 感染组之间存在适度差异。相比之下，在瘤胃中没有观察到差异。此外，通过差异丰度分析对未感染组和 BLV 感染组中占主导地位的细菌进行的调查表明，这两个微生物群中均不存在明显的细菌。因此，BLV感染可能在一定程度上影响了肠道微生物群。此外，还比较了未感染组和 BLV 感染组之间的细菌关联性。该分析结果表明，BLV 感染影响了两种微生物群中细菌关联的平衡，这可能与 BLV 相关的负面影响有关。因此，BLV 感染可能会对两个微生物群中细菌关联的平衡产生负面影响。亚临床 BLV 感染可能会影响瘤胃和肠道微生物群，这可能部分解释了 BLV 相关的负面影响。