Study On The Quality Characteristics And Mechanism Of Yak Meat From Different Parts

Yak(Bos grunniens)is mainly distributed in the qinghai-tibet Plateau and its adjacent areas,which can adapt to the low temperature,lack of oxygen and high solar radiation in the qinghai-tibet Plateau.In order to understand the quality characteristics and difference mechanism of different parts of Yak meat,three different parts of Yak meat were selected to analyze the quality characteristics of muscle such as shearing force,TPA and color.The Illumina RNA-seq high throughput sequencing technology platform was used to sequence,establish the transformed Green Group Library,analyze the GO functional annotation and KEGG pathway of differentially expressed genes.TMT proteomics was used to analyze the differential proteins,the GO functional annotation analysis,KEGG pathway analysis,PPI(protein-protein interaction)network analysis and correlation analysis with meat quality traits were performed.The differentially expressed genes and differentially expressed proteins were analyzed by combined transcriptome-proteomic analysis.The main research conclusions are as follows:1)The results showed that the color quality,tenderness quality and nutritional quality of Yak meat from different parts were different.The tenderness of JR was better than that of WJR and HGT,and that HGT was the worst.The shear force and elasticity of JR are significantly smaller than those of WJR and HGT(P<0.05),the cooking loss was significantly higher than WJR and HGT(P<0.05).The cooking loss of HGT was significantly lower than WJR and JR(P<0.05).There are significantly differences in L*,a*,b*and E color parameters(P<0.05).The L*and b*Values of HGT are significantly differences with JR and HGT(P<0.05).The a*Values of WJR is significantly differences with JR and HGT(P<0.05).The a*Values of WJR is significantly differences with JR and HGT(P<0.05).The highest amino acids in different parts of Yak meat were Met and Tyr,and the lower amino acids were Ser and Gly.Thr,Met,Gly,Ala,Cys,Tyr were significantly different differences among the three parts.2)The results showed that the difference express genes(DEGs)had an important effect on meat quality of Yak in different parts.There were 28.84GB total bases,1261 DEGs and 411 new genes in the three parts.There were total 295,713 and 603 DEGs in JR/HGT,WJR/HGT and WJR/JR comparison groups respectively,and which were 132,445,419 up-regulated DEGs,and 163,268,188 down-regulated DEGs respectively.The significantly difference GO function annotation for the DEGs mainly include growth factor activity,metalloexopeptidase activity,carboxypeptidase activity,cytokine activity,anion transmembrane transporter activity,receptor binding,metallopeptidase activity,chemokine activity and chemokine receptor binding.These annotations are mainly related to the functions of Cytokines,protein transporters and metabolic enzymes.The significantly difference KEGG pathway for the DEGs mainly include Oxidative phosphorylation,MAPK signaling pathway and Nitrogen metabolism.These pathways are mainly related to muscle oxidative phosphorylation,signal transduction of kinase and Nitrogen Metabolism.These studies of the DEGs revealed the internal regulation mechanism of yak meat in different parts.3)This study was designed to investigate the differences in the proteomes of yak muscles at different anatomical locations.In total,88 differentially expressed proteins(DEPs)were identified among striplon(WJR),slivsid(HGT)and chuck(JR).The number of DEPs was 34 in the WJR/JR comparison group,40 in the WJR/HGT comparison group,and 25 in the JR/HGT comparison group.13,28 and 23 DAPs among the DEPS were up-regulated,where as 21,12 and 3 DAPs were down-regulated.The quality analysis of DEPs showed heat shock proteins(HSPs)and structural proteins could be used as tenderness marker proteins for different parts of yak meat.The bioinformatics analysis revealed that DEPs are involved in glycolysis,protein structure and phosphorylation.PPI analysis revealed that myosin,HSPs and metabolic enzymes may have the potential to be biological markers.Correlation analysis between DAPs and quality traits of yak meat showed that there were 12 DEPs with significant correlation were correlated closely with quality traits.The expression of these proteins was down-regulated and up-regulated in different sites,and was closely related to the cell growth and death,carbohydrate metabolism,amino acid metabolism,protein binding,motility activity and unfolded protein binding.The significant difference of the expression of these key proteins in different parts is the internal reason of the difference of quality characteristics among WJR,JR and HGT.This study highlights that the DEPs were responsible for meat quality different.4)The Association analysis between Transcriptomics and Proteomics showed that the key DEGs and DEPs affecting meat quality were different in different parts of Yak meat.The number of DEGs and DEPs were 211 and 32 in the WJR/JR comparison group,585 and 40 in the WJR/HGT comparison group,510 and 25 in the JR/HGT comparison group,respectively.The number of association DEGs with DEPs is 4 in the WJR/JR comparison group,5 in the WJR/HGT comparison group,7 in the JR/HGT comparison group,respectively.The significantly difference GO function annotation for the DEGs and DEPs mainly include binding,carbohydrate metabolic process,cellular protein modification process,oxidoreductase activity,biological regulationand structural molecule activity.The significantly difference KEGG pathway for the DEGs and DEPs mainly include PPAR signaling pathway(map03320),Longevity regulating pathway-multiple species(map04213),Oxytocin signaling pathway(map04921),Jak-STAT signaling pathway(map04630)and Protein processing in endoplasmic reticulum(map04141).These studies highlights that the ssociation DEGs with DEPs were responsible for meat quality different.There were significantly differences in shearing force,TPA and color of Yak meat from different parts(P<0.05).A total of 1261 DEGs and 88 DEPs were identified from the three parts of yak meat.These DEGs and DEPs were mainly related to the functions of cytokines,protein transporters and metabolic enzymes,and the metabolic pathways involved are mainly related to Muscle Oxidative phosphorylation,glucose metabolism,Amino acid metabolism,kinase signal transduction and nitrogen metabolism.The significantly differences in the functions and metabolic pathways of these DEGs and DEPs are the internal factors that cause the differences in quality traits.We can understand the internal regulation mechanism of the difference of quality characteristics in different parts of Yak meat from the molecular level.