Evaluation of key miRNAs during early pregnancy in Kazakh horse using RNA sequencing

Background miRNA has an important role in cell differentiation, biological development, and physiology. Milk production is an important quantitative trait in livestock and miRNA plays a role in the amount of milk produced. Methods The role of regulatory miRNAs involved in equine milk production is not fully understood. We constructed two miRNA libraries for Kazakh horse milk production from higher-producing (H group) and lower-producing (L group) individuals, and used RNA-Seq technology to identify the differentially expressed miRNAs between the two milk phenotypes of Kazakh horses. Results A total of 341 known and 333 novel miRNAs were detected from the H and L groups, respectively. Eighty-three differentially expressed miRNAs were identified between the H and L group s, of which 32 were known miRNAs (27 were up-regulated, five were down-regulated) and 51 were novel miRNAs (nine were up-regulated, 42 were down-regulated). A total of 2,415 genes were identified. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that these genes were annotated to mammary gland development, mammary gland morphogenesis, tissue development and PI3K-Akt signaling pathways, insulin signaling pathway and TGF-beta signaling pathway, among others. Five miRNAs (miR-199a-3p, miR143, miR145, miR221, miR486-5p) were identified as affecting horse milk production and these five miRNAs were validated using qRT-PCR. Conclusions We described a methodology for the transcriptome-wide profiling of miRNAs in milk, which may help the design of new intervention strategies to improve the milk yield of Kazakh horses.

Equine Milk Production and Valorization of Marginal Areas—A Review

The equine dairy chain is renewing the interest toward horse and donkey breeding for the production of milk with potential health promoting properties. The dairy equine chain for human consumption could contribute to the rural eco-sustainable development for the micro-economies of those areas threatened by marginalization. As a part of the whole equine industry, and its possible impact in the modern and future society, the main traits of the equine dairy enterprise are reviewed with a special focus on management of animals and milk. Equine milk compositional and nutritional peculiarities are described as also related to milk hygiene and health issues. Scientific and technical aspects of the feeding management are considered in the frame of the emerging dairy equine enterprise, where pasture is an essential element that allows to match production goals for horses and donkeys, biodiversity preservation, as well as landscape safeguard.

Comparison of the principal proteins in bovine, caprine, buffalo, equine and camel milk

Proteomic analysis of bovine, caprine, buffalo, equine and camel milk highlighted significant interspecies differences. Camel milk was found to be devoid of β-lactoglobulin, whereas β-lactoglobulin was the major whey protein in bovine, buffalo, caprine, and equine milk. Five different isoforms of κ-casein were found in camel milk, analogous to the micro-heterogeneity observed for bovine κ-casein. Several spots observed in 2D-electrophoretograms of milk of all species could tentatively be identified as polypeptides arising from the enzymatic hydrolysis of caseins. The understanding gained from the proteomic comparison of these milks may be of relevance both in terms of identifying sources of hypoallergenic alternatives to bovine milk and detection of adulteration of milk samples and products.