Screening Of Residual Feeding Intake Related RNA Molecular Based On Next-Generation Sequencing In Qinchuan Cattle

In the beef cattle industry,feed investment accounts for more than 70%of the total cost of production,which is the main factor limiting the production of beef cattle.Therefore,it is one of the current breeding hotspots to improve the utilization efficiency of beef cattle feed from the genetic point of view and reduce the feeding cost.The residual feed intake(residual feed Intake,RFI)is an index to measure the efficiency of animal feed utilization,which is independent of the average daily gain,belongs to the medium heritability,and the breeding of individuals with low residual intake can accelerate the genetic progress and improve the efficiency of feed utilization.In order to explore the molecular genetic mechanism affecting the feed utilization efficiency of Qinchuan cattle,three experiments were carried out in this study,1)Differential and correlation analysis of growth traits between high and low RFI Qinchuan cattleIt is of great economic value to explore the correlation between traits easy to get and such traits which are not easy to measure.In this study,the growth traits,collected from 16 high and 13 low RFI Qinchuan cattle,were analyzed by using the TTEST for differential and CORR for correlation process in SAS 9.2,which aim is to explore the differential of growth traits and the correlation with RFI in different RFI groups.The results showed that the waist width and feed intake of the high RFI group were significantly higher than that of the low RFI Group(P<0.01),and the chest depth significantly higher than that of the low RFI group.And there is a significant correlation between RFI and FI in High RFI group(r=0.61,P<0.01).In the low RFI group,there was a significant negative correlation between RFI and Rump width(R==-0.66,P<0.05),and strongly significant correlation with FI(r=0.9,P<0.01).2)Identifying key genes related to residual feed intake of Qinchuan cattle based on RNA-seqAnalyzing the feed utilization efficiency of animal from molecular level has high economic and scientific significance.In this study,bovine duodenal tissue,which collected from 4 high RFI and 4 low RFI Qinchuan,were used as test materials to carry out 6G transcriptome sequence,and 43 differential expression genes were obtained(P,FDR,q<0.05).The results of GO analysis and pathway analysis of differential expression gene showed that differential genes were enriched in biological processes such as fatty acid metabolism,amino acid metabolism,feeding behavior,inflammatory response and immune response.After integration analysis,8 candidate genes related to RFI were detected(TFF2,LOC509961,RARRES1,PRDX4,CCK,CCL5,ACOT2 and HPD).3)Identifying candidate miRNAs related to RFI using small RNA sequencing technologyExcavating the miRNAs associated with RFI and predicting its regulatory relationship with the target gene is a key method for analyzing the expression and regulation of RFI-related genes.Small RNA sequencing was carried out using the same tissue samples in test 2.Results shown that 34 differential expression miRNA were detected(P<0.05,FDR,q<0.05),in which 3 miRNAs were up-regulation in the high RFI group and the rest down-regulation.Through bioinformatics analysis,8 key miRNAs related to RFI were obtained(bta-miR-146b,bta-miR-148b,bta-miR-615,bta-miR-363,bta-miR-2890,bta-miR-2892,bta-miR-11972,bta-miR-11985),and predicted that the bta-miR-11972 target gene was HPD,TH,ASCL1,miR-146 was GRP and miR-615 was HPD.