Exploring the role of immune-related microRNAs in newborn calves’ circulation 2259711

Abstract

Abstract Introduction Bovine colostrum provides nutrients and bioactive factors including antibodies, microRNAs (miRNAs), among others that are essential for newborn calves. We aimed to assess immune miRNAs in bovine colostrum and to evaluate the role of circulatory miRNAs in neonatal calf health. Methods Beef-on-dairy calves were randomly assigned to a colostrum-fed (CF) or colostrum-deprived (CD) group after birth (n = 10/group). Calves in the CF were tube-fed pooled colostrum (10% BW/calf) ∼4 hours after birth, while calves in the CD were fed 2.8L of a commercial milk replacer (MR) as their first feeding. Whole blood was collected from all calves prior to and after their first feeding. Colostrum, MR, and blood samples were subjected to RNA extraction, small RNA sequencing using Illumina platform, and differential expressed miRNAs were analyzed using DESeq2 in R. Significance was declared at P-adj ≤ 0.05. Results MicroRNAs miR-22-3p and miR-2285 were upregulated in bovine colostrum and in blood of calves that were CF vs CD post-first feeding. In contrast, circulatory miR-6775 and miR-21-5p were downregulated post-feeding in CF relative to CD. miR-22-3p is involved in T cell differentiation while miR-2285 has been linked to milk fat metabolism in mammary epithelial cells. Conclusion Our findings highlight functional miRNAs that may modulate immune pathways in calves. However, the ability to intestinal absorption of microRNAs from colostrum remains unclear. Funding Source Agriculture and Food Research Initiative Competitive Grant no. 2023-67015-39081 from the United States Department of Agriculture (USDA) — National Institute of Food and Agriculture (NIFA) Topic Categories Veterinary and Comparative Immunology (VET)