Large numbers of miRNAs are found in biofluid exosomes. We isolated~50-200 nm diameter exosomes from four types of porcine biofluid (urine, plasma, semen, and bile) using serial centrifugation and ultracentrifugation procedures. A total of 42.15 M raw data were generated from four small RNA libraries. This produced 40.17 M map-able sequences, of which we identified 204 conserved miRNAs, and 190 novel candidate miRNAs. Furthermore, we identified 34 miRNAs specifically expressed in only one library, all with well-characterized immunerelated functions. A set of five universally abundant miRNAs (miR-148a-3p, miR-21-5p, let-7f-5p, let-7i-5p, and miR-99a-5p) across all four biofluids was also found. Function enrichment analysis revealed that the target genes of the five ubiquitous miRNAs are primarily involved in immune and RNA metabolic processes. In summary, our findings suggest that porcine biofluid exosomes contain a large number of miRNAs, many of which may be crucial regulators of the immune system.

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BackgroundOne of the most extensively applied animal feed additives is yeast culture (YC), which can increase production efficiency by altering gastrointestinal tract (GIT) microbiota. However, its use is still limited in waterfowl. Geese are the ideal model to study the interaction between dietary and GIT, due to their adaptation to consume different roughage sources. Therefore, the effect of YC supplementation at different concentrations (0%, 0.5%,1.0%,2.0% and 4.0%) on the GIT microbiota of geese was investigated in the present study. ResultsThree hundred Sichuan white geese with healthy and similar body weight (BW: 95.57 ± 2.42 g) were randomly divided into five groups: i) basal diet (control), ii) basal diet+0.5%YC (treat1), iii) basal diet+1.0% YC (treat2), iv) basal diet+2.0% YC (treat3), and v) basal diet+4.0% YC (treat4). After 10 weeks, slaughter and collected the cecum contents, then analysis GIT microbiota by high-throughput sequencing. The results showed that YC supplementation did not significantly affect α-diversity (P ＞0.05). Principal coordinates analysis showed an obvious separation between control and treat4. The dominant phyla were Firmicutes and Bacteroidetes whereas the predominant genera were Alistipes and Desulfovibrionaceae. The relative abundance of Firmicutes significantly increased in the treat1 group, whereas that of Bacteroidetes significantly decreased in the treat4 group. Dietary YC increased the proportion of beneficial bacteria, such as Parabacteroides, Enterococcus, Streptococcus and Pseudomonas, particularly in group treat2. Furthermore, treat3 significantly improved the body weight and feed utilization of geese.ConclusionCollectively, these findings demonstrate that dietary YC supplementation tends to increase species diversity and richness of GIT microbiota in geese. This increases the proportion of beneficial bacteria which improves amino acid and carbohydrate metabolism. Moreover, YC increases the relative abundance of Firmicutes that promote energy utilization and nutrition absorption, thereby improving the growth performance of geese. This dietary strategy based on feed additives is an effective method to maintain the health of the geese GIT and to improve growth efficiency.