Detection and profiling of microRNAs in butter

Milk is the body fluid richest in microRNAs (miRNAs), which are small (18-25nt) non-coding RNAs, regulating many biological processes and thus influencing human health. With the objective of determining their bioavailability in processed dairy products, we studied three commercial butters. To examine the presence or not of miRNAs in butter, we first investigated six miRNAs by RT-qPCR. Following the affirmative result, we established butter miRNomes using small-RNA-Seq, which identified 526 miRNAs, including 50% in common with a milk and milk fat miRNome. The three butters did not have exactly the same TOP 30 miRNAs and were not the exact mirror of the TOP 30 of the miRNAs already reported in Holstein milk and milk fat miRNomes, suggesting differences during the butter production process or storage. Prediction of the influence of the TOP 30 butter miRNAs showed potential effects on cell life and regulation of gene expression that could affect consumer health. In the future, the effects of miRNAs bioavailability on the health of human consuming dairy products will need to be considered. Our results highlight the importance of expanding our understanding of the bioavailability of food miRNAs, including in various processed dairy foods. microRNA profiles of 3 commercial butter samples, generated by deep sequencing using Illumina HISeq 4000