Abstract:

As an essential nutrient, maternal milk also encompasses various bioactive components such as microribonucleic acids (microRNA). microRNA in milk exists in extracellular vesicles (EVs) and can be absorbed into the host's enterocytes, modulating the growth and development of small ruminants, the latter has a membrane structure enclosed by a kind of lipid bilayer with some resistance. Extracellular vesicles derived from milk are often isolated before the analysis of microRNA profiles. Currently, extracellular vesicles are mainly extracted by differential centrifugation, density gradient centrifugation, and precipitation. Each method has specific advantages and disadvantages, an appropriate extraction method should be selected according to sample characteristics and experimental conditions, and extracellular vesicles isolated still need to be identified by electron microscopy, flow cytometry, or nanoparticle tracking analysis. The analysis of microRNA profiles is mainly divided into two parts: Sequencing and data analysis, The former needs to select a suitable sequencing platform according to the requirement, and the latter includes multiple steps such as data quality control, alignment with the database, differential expression microRNA analysis and microRNA function prediction. For each step, there are various types of analysis software to choose from, analysis methods should be reasonably combined according to the characteristics of sequencing data and software to carry out more accurate and effective information mining on sequencing data. this paper reviewed the research advances in the ruminants' microRNA, aiming to use corresponding technology to research the profiles and function of microRNA derived from milk, providing references for modulating the growth and development of small ruminants.

Key words: ruminant, milk, microRNA, small RNA sequencing