Identification and characterization of hypothalamic circular RNAs associated with bovine residual feed intake.

Residual feed intake (RFI) is crucial economic indicator used for calculating the feed efficiency of growing beef cattle. circRNA plays an important biological role in gene transcriptional regulation, but little is known about its potential functional regulation underlying RFI phenotypic variation. As the core center of regulation of animal feeding, the hypothalamus is closely associated with RFI. Therefore, the present study aimed to identify the key genes and functional pathways contributing to variance in cattle RFI phenotypes using RNA sequencing from hypothalamic tissue samples, in order to gain insight into the potential regulatory role of circRNAs in bovine RFI phenotypic variation. Differentially expressed genes were detected by RNA sequencing for beef cattle in the high and low RFI groups, followed by GO, KEGG enrichment, and circRNA-miRNA co-expression network analysis. A total of 257 circRNAs were differentially expressed between the two groups, with 128 significantly upregulated and 129 significantly downregulated genes in H group compared to L group. Among them, 9 unique circRNAs were present in group L and 4 unique circRNAs were present in group H. GO and KEGG enrichment analysis of the source genes of the differentially expressed circRNAs revealed that they were mainly involved in metabolic processes, such as cellular metabolic processes, cellular macromolecular metabolic processes, and regulatory pathways related to nutrient metabolism, including protein and amino acid metabolism, as well as vitamin metabolism and pancreatic secretion associated with the animal feeding behavior. The circRNAs detected in this study were mostly novel, and have not been investigated directly to be associated with the RFI phenotype. Interestingly, most miRNAs of differentially expressed circRNAs predicted based on the circRNA-miRNA co-expression network analysis by using top 50 differentially expressed circRNAs and 13 unique circRNAs, have been reported to be related to animal RFIs, implying that circRNAs in bovine hypothalamic tissue may regulate phenotypic variation in RFI through miRNAs. The study results illustrate the complex biological functions of the hypothalamus in regulating feed efficiency and showing the potential role of circRNAs in the feeding behavior regulation of livestock, which would contributing to expanding the understanding of circRNA.

Effects of soya oligosaccharides and soya oligopeptides on lipid metabolism in hyperlipidaemic rats.

In the present study, we aimed to examine the effects of soya oligosaccharides (SOS) and soya oligopeptides (SOP) on blood lipid levels, release of vasoactive substances, antioxidant activity and faecal bile acid (FBA) excretion in rats fed a high-fat diet (HFD). Male Sprague-Dawley rats were evenly divided into five groups according to diets as follows: regular diet (control), HFD, HFD enriched with 2 % of SOS (SOS), HFD enriched with 3 % of SOP (SOP) and HFD enriched with 2 % SOS and 3 % SOP (SOSP). The results showed that SOS and SOP significantly reduced plasma total cholesterol, LDL-cholesterol and TAG, whereas HDL-cholesterol concentration was significantly increased. Furthermore, SOS and SOP reduced plasma apoB, apoE and the apoB:apoAI ratio, whereas apoAI was significantly increased. Moreover, SOS and SOP also reduced plasma thromboxane A2 (TXA2) and the TXA2:prostacyclin (PGI2) ratio, whereas plasma PGI2 and nitric oxide were significantly increased. In addition, SOS and SOP significantly reduced serum and liver malondialdehyde concentrations and increased FBA excretion. However, we did not observe obvious influences of SOS and SOP on superoxide dismutase activities in the liver of HFD-fed rats. The combination of 2 % SOS and 3 % SOP showed a more marked effect than SOS or SOP alone in improving the lipid profile, release of vasoactive substances and increasing FBA excretion (P < 0.05). In summary, SOS and SOP might help prevent atherosclerosis through improving abnormal blood lipid levels, regulating vasoactive substances and protecting against oxidative stress.