Effect of Concentrate Supplementation on the Expression Profile of miRNA in the Ovaries of Yak during Non-Breeding Season.

Yak (Bos grunniens) is an important and remarkable livestock species that survives in the challenging environment of the Qinghai-Tibetan Plateau. However, its growth rate is slower and reproductive potential is generally lower than cattle. Meanwhile, it has been reported that enhanced nutrition improves the reproductive efficiency of animals. The purpose of this study was to investigate the effect of concentrate supplementation on the miRNA expression profile in the ovaries of yak during the non-breeding season. The study displayed that non-breeding season supplementation significantly improved growth performance, serum biochemical indicators, and reproductive hormone concentrations in yaks. In this study, we also examined the differential expression analysis of miRNA in the ovaries of yak during non-breeding seasons using Illumina Hiseq sequencing technology. As a result, 51 differentially expressed miRNAs were found in the experimental group (CS) and control group (CON). Gene Ontology (go) and Kyoto Genome Encyclopedia (KEGG) analysis of target genes showed that beta-alanine metabolism; tryptophan metabolism; sphingolipid metabolism; alanine, aspartate and glutamate metabolism; and the inositol phosphate metabolism pathway attracted our attention. Based on qRT-PCR, seven miRNAs were assessed to verify the accuracy of the library database. We predicted and identified potential miRNA target genes, including LEP, KLF7, VEGFA, GNAQ, GTAT6, and CCND2. miRNA and corresponding target genes may regulate yaks' seasonal reproduction through their nutritional status. This study will provide an experimental basis for improving the reproductive efficiency of yaks by supplementation in the non-breeding season.