Changes in exosomal circulating microRNAs in grazing cattle

To investigate the potential effect of grazing movement on miRNA circulation in cattle, here we profiled miRNA expression in centrifugally prepared exosomes from the plasma of both grazing and housed Japanese Shorthorn cattle. Microarray analysis of the c-miRNAs resulted in detection of a total of 231 bovine exosomal miRNAs in the plasma, with a constant expression level of let-7g across the duration and cattle groups. Expression of muscle-specific miRNAs such as miR-1, miR-133a, miR-206, miR-208a/b, and miR-499 were undetectable, suggesting the mildness of grazing movement as exercise. Changes in miRNA expression in plasma exosome of cattle was measured at during 0, 1, 2 and 4 months of grazing or housing. Plasma exosome samples prepared from three cattle for each treatment were collected and mixed within the treatment at each time for microarray analysis .