AUTHOR=Mao Yongxia , Wang Feifei , Kong Weiyi , Wang Ruiling , Liu Xin , Ding Hui , Ma Yun , Guo Yansheng 

TITLE=Dynamic changes of rumen bacteria and their fermentative ability in high-producing dairy cows during the late perinatal period

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1269123

DOI=10.3389/fmicb.2023.1269123

ISSN=1664-302X

ABSTRACT=<sec><title>Background</title><p>High-producing dairy cows face varying degrees of metabolic stress and challenges during the late perinatal period, resulting in ruminal bacteria abundance and their fermentative ability occurring as a series of changes. However, the dynamic changes are still not clear.</p></sec><sec><title>Aims/methods</title><p>Ten healthy, high-producing Holstein dairy cows with similar body conditions and the same parity were selected, and ruminal fluid from the dairy cows at postpartum 0, 7, 14, and 21 d was collected before morning feeding. 16S rRNA high-throughput sequencing, GC-MS/MS targeted metabolomics, and UPLC-MS/MS untargeted metabolomics were applied in the study to investigate the dynamic changes within 21 d postpartum.</p></sec><sec><title>Results</title><p>The results displayed that the structures of ruminal bacteria were significantly altered from 0 to 7 d postpartum (<italic>R</italic> = 0.486, <italic>P</italic> = 0.002), reflecting the significantly declining abundances of Euryarchaeota and Chloroflexi phyla and <italic>Christensenellaceae, Methanobrevibacter</italic>, and <italic>Flexilinea</italic> genera (<italic>P</italic> &lt; 0.05) and the obviously ascending abundances of <italic>Ruminococcaceae, Moryella, Pseudobutyrivibrio</italic>, and <italic>Prevotellaceae</italic> genera at 7 d postpartum (<italic>P</italic> &lt; 0.05). The structures of ruminal bacteria also varied significantly from 7 to 14 d postpartum (<italic>R</italic> = 0.125, <italic>P</italic> = 0.022), reflecting the reducing abundances of <italic>Christensenellaceae, Ruminococcaceae</italic>, and <italic>Moryella</italic> genera (<italic>P</italic> &lt; 0.05), and the elevating abundances of <italic>Sharpea</italic> and <italic>Olsenella</italic> genera at 14 d postpartum (<italic>P</italic> &lt; 0.05). The metabolic profiles of ruminal SCFAs were obviously varied from 0 to 7 d postpartum, resulting in higher levels of propionic acid, butyric acid, and valeric acid at 7 d postpartum (<italic>P</italic> &lt; 0.05); the metabolic profiles of other ruminal metabolites were significantly shifted from 0 to 7 d postpartum, with 27 significantly elevated metabolites and 35 apparently reduced metabolites (<italic>P</italic> &lt; 0.05). The correlation analysis indicated that propionic acid was positively correlated with <italic>Prevotellaceae</italic> and <italic>Ruminococcaceae</italic> (<italic>P</italic> &lt; 0.05), negatively correlated with <italic>Methanobrevibacter</italic> (<italic>P</italic> &lt; 0.01); butyric acid was positively associated with <italic>Prevotellaceae, Ruminococcaceae</italic>, and <italic>Pseudobutyrivibrio</italic> (<italic>P</italic> &lt; 0.05), negatively associated with <italic>Christensenellaceae</italic> (<italic>P</italic> &lt; 0.01); valeric acid was positively linked with <italic>Prevotellaceae</italic> and <italic>Ruminococcaceae</italic> (<italic>P</italic> &lt; 0.05); pyridoxal was positively correlated with <italic>Flexilinea</italic> and <italic>Methanobrevibacter</italic> (<italic>P</italic> &lt; 0.05) and negatively correlated with <italic>Ruminococcaceae</italic> (<italic>P</italic> &lt; 0.01); tyramine was negatively linked with <italic>Ruminococcaceae</italic> (<italic>P</italic> &lt; 0.01).</p></sec><sec><title>Conclusion</title><p>The findings contribute to the decision of nutritional management and prevention of metabolic diseases in high-producing dairy cows during the late perinatal period.</p></sec>