Kim Yo-Han, Kimura Atsushi, Sugino Toshihisa, Sato Shigeru
Department of Large Animal Internal Medicine, College of Veterinary Medicine, Kangwon National University, Chuncheon, South Korea.
Veterinary Teaching Hospital, Faculty of Agriculture, Iwate University, Morioka, Japan.
Front Vet Sci. 2022 Aug 26;9:948545. doi: 10.3389/fvets.2022.948545. eCollection 2022.
We investigated the temporal dynamics of ruminal pH and the composition and predicted functions of the rumen bacterial community in Holstein cows during the periparturient period. Eight multiparous Holstein cows (body weight; 707.4 ± 29.9 kg, parity; 3.6 ± 0.6) were used for continuous reticulo-ruminal pH measurement, among which five were also used for bacterial community analysis. Rumen fluid samples were collected at 3 weeks before and 2 and 6 weeks after parturition, and blood samples were collected 3 weeks before and 0, 2, 4, and 6 weeks after parturition. After the parturition, reduction in the 1-h mean reticulo-ruminal pH was associated with a significant ( < 0.05) increase in total volatile fatty acid concentration. However, with the exception of a significant change in an unclassified genus of ( < 0.05), we detected no significant changes in the compositions of major bacterial phyla or genera or diversity indices during the periparturient period. On the basis of predicted functional analysis, we identified a total of 53 MetaCyc pathways (45 upregulated), 200 enzyme commissions (184 upregulated), and 714 Kyoto Encyclopedia of Genes and Genomes orthologs (667 upregulated) at 6 weeks postpartum that were significantly ( < 0.05) different to those at 3 weeks prepartum. Among the 14 MetaCyc pathways ( < 0.05) in which pyruvate is an end product, PWY-3661 [log2-fold change (FC) = 5.49, false discovery rate (FDR) corrected < 0.001] was the most highly upregulated pyruvate-producing pathway. In addition, P381-PWY [adenosylcobalamin biosynthesis II (aerobic); FC = 5.48, FDR corrected < 0.001] was the second most upregulated adenosylcobalamin (Vitamin B12)-producing pathway. In contrast, PWY-2221 (FC = -4.54, FDR corrected = 0.003), predominantly found in pectinolytic bacteria, was the most downregulated pathway. Our findings indicate that changes in rumen bacterial community structure are not strictly associated with transitions in parturition or diet; however, we did observe changes in reticulo-ruminal pH and the metabolic adaptation of predicted functional pathways. Consequently, predictive analysis of postpartum functional pathways may enable us to gain insights into the underlying functional adaptations of bacterial communities in Holstein cows during the periparturient period.
我们研究了围产期荷斯坦奶牛瘤胃pH值的时间动态变化以及瘤胃细菌群落的组成和预测功能。选用8头经产荷斯坦奶牛（体重707.4±29.9 kg，胎次3.6±0.6）进行连续的瘤网胃pH值测量，其中5头还用于细菌群落分析。在分娩前3周、分娩后2周和6周采集瘤胃液样本，在分娩前3周、分娩后0、2、4和6周采集血样。分娩后，1小时平均瘤网胃pH值的降低与总挥发性脂肪酸浓度的显著升高（P<0.05）相关。然而，除了一个未分类属的显著变化（P<0.05）外，我们在围产期未检测到主要细菌门或属的组成或多样性指数有显著变化。基于预测功能分析，我们发现在产后6周共有53条MetaCyc途径（45条上调）、200个酶委员会（184个上调）和714个京都基因与基因组百科全书直系同源物（667个上调）与产前3周有显著差异（P<0.05）。在以丙酮酸为终产物的14条MetaCyc途径（P<0.05）中，PWY-3661[log2倍变化（FC）=5.49，错误发现率（FDR）校正P<0.001]是上调幅度最大的丙酮酸生成途径。此外，P381-PWY[有氧条件下腺苷钴胺素生物合成II；FC = 5.48，FDR校正P<0.001]是上调幅度第二大的腺苷钴胺素（维生素B12）生成途径。相反，主要存在于果胶分解细菌中的PWY-2221（FC = -4.54，FDR校正P = 0.003）是下调幅度最大的途径。我们的研究结果表明，瘤胃细菌群落结构的变化与分娩或饮食的转变并不严格相关；然而，我们确实观察到瘤网胃pH值的变化以及预测功能途径的代谢适应性变化。因此，对产后功能途径的预测分析可能使我们深入了解围产期荷斯坦奶牛细菌群落的潜在功能适应性。
