In order to explore the species and functions of microRNAs (miRNAs) in donkey milk exosomes, Illumina sequencing technique was used to sequence the small non-coding RNAs (sRNAs) in donkey milk exosomes, and identify the miRNAs in them through bioinformatic analysis using human milk miRNAs as the control. After quality control, the length of the sRNAs in donkey milk exosomes was mainly distributed between 18 and 22 nt, and a total of 212 miRNAs were identified, including 16 known ones and 196 new ones. Gene Ontology (GO) enrichment analysis showed that the functions of the miRNAs in donkey milk exosomes were similar to those of human milk miRNAs, such as constituting cells, organelles and other components, binding and catalytic activity and participating in the processes of cell metabolism and biological regulation. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that the miRNAs in donkey milk exosomes participated in the synthesis and secretion of aldosterone, the Hedgehog signaling pathway, mitochondrial regulation and cancer pathways.

In this study, density-gradient centrifugation was used to extract bovine milk exosomes, and the small non-coding RNA (sRNA) in the exosomes were sequenced by Illumina sequencing technology to explore the expression profile of bovine milk microRNAs (miRNAs). Through quality control of the original sequence, a total of 3899629 pure sRNA sequences were obtained, and their length was concentrated at 28 nt. By comparison with the database, 61 known miRNAs and 346 novel miRNAs were identified. The results of gene ontology enrichment analysis showed that miRNAs from bovine milk exosomes played a critical role in various biological processes such as cell process, single organism process and metabolic process. It mainly consisted of cells and organelles and was mainly involved in molecular functions such as binding, catalytic activity and transporter activity. The results of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the known miRNAs and the new miRNA target genes were significantly enriched in pertussis (ko05133), chemokine signal pathway (ko04062), endocytosis (ko04144), lysosome (ko04142) and other pathways, and bovine milk exosome miRNAs played an important role in specific signaling pathways.