Study On The Effects Of Exercise On Meat Quality And Genetic Basis Of Captivity Sunit Sheep

Sunit sheep is a local breed sheep in Inner Mongolia.It is famous for its tender meat.In this study,the exercise and captivity Sunit sheep were used as the test objects.The growth performance,slaughter performance and mutton quality of Sunit sheep under two conditions were measured.Transcriptome sequencing(RNAseq)technology was used to sequence the longissimus dorsi muscles of the two groups.The differentially expressed genes were screened.The physiological functions and metabolic pathways of the differential genes were analyzed.The fatty acid composition was determined by gas chromatography-mass spectrometry,and the differential gene was verified by q RT-PCR.The results are as follows:(1)In terms of growth performance,slaughter performance and meat quality:the body length,carcass depth,slaughter rate and shear force of the exercise group were significantly higher than those of the captivity group(P < 0.05);the back fat thickness,p H24,IMF content,redness value,yellowness value and brightness value of the exercise group were significantly lower than those of the captivity group(P< 0.05);in terms of fatty acid types,in the longissimus dorsi muscle of the exercise group,saturated fatty acids(lauric acid,myristic acid,palmitic acid and stearic acid)were significantly higher than the captivity group(P <0.05);the content of monounsaturated fatty acids and polyunsaturated fatty acids was significantly lower than the captivity group(P <0.05)(myristic acid,oleic acid,trans-linoleic acid,arachidic acid,γ-Linolenic acid,α-linolenic acid,arachidonic acid,arachidonic acid,eicosapentaenoic acid and arachidonic acid).The results showed that exercise changed the fatty acid composition of Sunite sheep,and the color and tenderness of mutton in the captivity group were better than those in the exercise group.(2)621 differentially expressed genes were screened by RNA-seq technology of longissimus dorsi muscle in exercise and captivity Sunit sheep,385 genes are up-regulated genes and 236 are down regulated genes.Through GO functional annotation and KEGG pathway analysis,it is found that those genes were involved in biological processes and metabolic pathways such as lipid metabolism,glycolytic metabolism and energy metabolism.Thirteen candidate genes related to meat quality traits were obtained,including HK2,HKDC1,TPI1,PKM,PGK1,ACSF3,ACSL3,AKR1B1,GK,SCP2,PLIN1,LPIN1,DGAT2.(3)Twelve genes(PLIN1,ACSL3,SCP2,EIF4EBP1,SYNJ2,TPI1,PKM,SETD7,DHDH,AKR1B1,SDS,GOT1)were randomly selected for real-time PCR verification.The results of gene expression were consistent with RNA-seq,indicating that the results of RNA-seq were accurate,reliable and effective.In this experiment,the differentially expressed genes in longissimus dorsi muscle of exercise and captivity Sunit sheep were screened,and the functional and metabolic pathways involved in the differentially expressed genes were obtained.Lipid metabolism,glycolysis metabolism and energy metabolism were all related to meat quality.This study can provide some reference for further research on meat quality of Sunit sheep.