Can we use miRNA to certify raw milk from fresh grass-fes cows?

Abstract

MicroRNAs (miRNAs) are small, noncoding RNAs that hybridize mRNA by complementary sequences. miRNAs act as key regulators of diverse biological and developmental processes in eukaryotes, including cell proliferation and differentiation, apoptosis, immune system development, and immune responses. Their presence in all tissues and organic fluids make them good, non-invasive biomarkers for milk quality. We and others have demonstrated that miRNA profiles found in raw milk change according to the cow’s diet and/or the milk production system. Our aim here is to study miRNA differential expression in milk in order to authenticate the production system of the milk. Tank milk from dairy farms managed under different production systems in Asturias (north of Spain) was collected, milk fractions separated (fat and cells), and total RNA isolated. Differential expression of previously identified miRNAs cells was analysed and compared among different production systems. Bta-mir-2285e was identified as a possible miRNA marker of milk produced by cows fed on fresh-grass. This study sets a precedent for the use miRNAs as a certification tool for agro-food products, but also can help us to understand the functionality of milk produced under different systems.