| The purpose of this experiment was to study the effects of SCD1 and SREBP-1 gene expression in muscle and blood of pure Simmental cattle raised in alpine grassland on their fatty acid composition,and to provide basic data for the preservation of excellent genetic genes in future breeding.In this experiment,the blood and muscles of pure Simmental male cows raised in alpine grassland were taken as the research objects.the composition and content of fatty acids were determined by high performance gas chromatography-mass spectrometry(GC-MS),the relative m RNA expression of SCD1 and SREBP-1 genes was determined by real-time fluorescence quantitative PCR,and the polymorphism of SCD1 and SREBP-1 genes was detected by first-generation sequencing and agarose gel electrophoresis,respectively,and the effects of SCD1 and SREBP-1 genes on blood and intramuscular fatty acids of Simmental cows raised in alpine grassland were further analyzed Test results are as follows:Simmental cattle raised in alpine grassland have high contents of palmitic acid,stearic acid,oleic acid and linoleic acid in both blood and intramuscular fatty acids,and their composition rules are similar.The outer ridges of Simmental male cows have high content of palmitic acid(30.68% and 30.85%)and stearic acid(18.12% and 16.74%),and low content of myristic acid(2.01% and 2.02%).Ox’s plate tendon and cow’s cucumber strip have high oleic acid content(43.19% and 42.64%),while male cow’s anterior tendon has high PUFA content(14.12% and 11.29%).The ratio of PUFA/SFA in blood of Simmental cattle was higher than WHO recommended standard(≥ 0.4),but lower than IMF recommended standard.The n-6/n-3 ratio of Simmental cows is within the range of FAO recommended standard(5～10),while bulls are higher than the recommended standard.The mean expression levels of SREBP-1 m RNA and SCD1 m RNA in blood of simmental male cows raised in alpine grassland were 0.20 and 0.02,and 0.01 and 0.14,respectively.The mean expression of SCD1 m RNA in longissimus dorsi muscle was 0.05,and the percentage of MUFA contained in it was 36%,showing consistency.SCD1 gene has significant effects on C16:0,C18:0,C18:1,SFA and MUFA percentage,MUFA/SFA ratio,C14 index,C18 index and total unsaturated index.SREBP-1 gene has significant effects on C16:0,SFA,MUFA/SFA ratio,C14 index,C16 index,C18 index and total unsaturated index.SCD1 gene was positively correlated with C16:1,C18:1 and MUFA in blood and muscle of Simmental cattle,while SREBP-1 gene was positively correlated with C16:0,C16:1,C18:0,C18:1 and MUFA in blood,C16:0 and C18:0 in muscle of Simmental cattle SCD1 and SREBP-1 genes have great genetic effects on fatty acids,and can be used as important candidate genes for breeding and evaluating Simmental cattle breeds raised in alpine steppe.SCD1 of Simmental cattle raised in alpine grassland is polymorphic at 878,showing three genotypes: CC,TT and CT.SREBP-1 has a length polymorphism of 84 bp,and two genotypes,LL and LS,are detected.SCD1 gene polymorphism has significant difference only in stearic acid and SFA of cow blood,showing that CC type has high content of stearic acid(27.11%)and SFA(52.96%),which is significantly higher than the same fatty acid content of CT type(p < 0.05),while SCD1 genotype has no significant difference between longissimus dorsi and bull blood.There is no significant difference between LL and LS genotypes of SREBP-1 gene and fatty acid composition. |
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