Folic acid supplementation regulates key immunity-associated genes and pathways during the periparturient period in dairy cows.

Objective: The current research was aimed to profile the transcriptomic picture of the peripheral blood lymphocytes (PBLs) associated with immunity in Chinese Holsteins supplemented orally with coated folic acid during the periparturient period.

Methods: The total of 123 perinatal cows were selected for this study and divided into three groups; group A (n = 41, 240mg/ 500 kg cow/day), group B (n = 40, 120mg/ 500 kg cow/day) and group C (n = 42, 0mg/cow/day) based on the quantity of folic acid fed. Three samples of PBLs were selected from each folic acid treated group (High, Low, and Control) and RNA sequencing method was carried out for transcriptomic analysis.

Results: The analysis revealed that a higher number of genes and pathways were regulated in response to high and low folic acid supplementation compared to the controls. We reported the novel pathways (TNF signaling, Antigen processing and presentation, Staphylococcus aureus infection and NF-kappa B signaling pathways) and the key genes (e.g. CXCL10, TNFRSFIA, CD4, BOLA-DQB, NFKBIA, and TNFSF13) having great importance in immunity and anti-inflammation in the periparturient cows in response to coated folic acid treatment.

Conclusion: Collectively, our study profiled first-time transcriptomic analysis of bovine lymphocytes and compared the involved cytokines, genes, and pathways between High vs. Control and Low vs. Control. Our data suggest that the low folic acid supplementation (120 mg/500 kg) could be a good choice to boost appropriate immunity and anti-inflammation as well as might being applied to the health improvement of perinatal dairy cows.