Effects Of Artemisia Ordosica On Fatty Acid Composition Of Cashmere Goat Muscle Was Studied Based On Metabolomics And Transcriptomics

Pen-fattening is one of the main feeding methods for cashmere goats,but the Penfattening mode increases the content of saturated fatty acids(SFA)in lamb and reduces the content of n3-polyunsaturated fatty acids(n-3PUFA),which is beneficial to human health.Nutritional intervention is one of the main measures to regulate the fatty acid composition of mutton.The addition of flavonoids,polyphenols and their extracts to the diet significantly reduced the content of SFA and n-6 PUFA in animal muscle and increased the content of C18:3n3 and n-3 long-chain polyunsaturated fatty acids(n-3LCPUFA).This thesis used Albass white cashmere goat as a test animal to study the effect of adding Artemisia ordosica to the diet on the composition of fatty acids(FA)in muscle tissues,and used metabolomics and transcriptomics to explore the mechanism of its influence from the gene expression profile of the longest dorsal muscle,combined with the activities of transcription factors and enzymes related to blood and muscle fat metabolism,so as to provide a theoretical basis for the scientific application of Artemisia ordosica,improving the FA composition of mutton and improving the nutritional value of mutton in the production of cashmere goats.This thesis included four experiments.The single-factor completely randomized trial design was used.Fourty healthy Albass white cashmere goat(lambs)with similar age were divided into two groups,the control group(CON)and the Artemisia ordosica(ARI).The control group was fed a basal diet without Artemisia ordosica,and the experimental group was feed 3% Artemisia ordosica instead of equal fully mixed roughage of the basal diet.The prefeed period was 14 days and the experimental period was 90 days.Blood was collected at the end of the fattening test,samples of the Longissimus,biceps,gluteal and brachial triceps muscles were taken for the determination of FA composition and lipid metabolismrelated enzyme activity after goat were slaughtered.Samples of the Longissimus muscle were also snap-frozen in liquid nitrogen for transcriptomic analysis.It was to investigate the effect of dietary addition of Artemisia ordosica on the composition of FA in cashmere goat plasma and longis,biceps,glutes and brachial triceps in experiment 1.The results showed that compared with the CON group,the content of n-3LCPUFA and P/S in the muscle and plasma of cashmere goats in the ARI group were significantly increased.The content of SFA,C18:0 in the longest dorsal muscle,and C16:0in gluteus,triceps brachius and biceps femoris decreased in the four muscles;The contents of n-6 PUFA/n-3 PUFA in the longest dorsi,triceps brachia and plasma were significantly reduced(P<0.05),and the contents of C18:3n3 and C22:6n3 in the other three muscles and plasma except the biceps femoris were significantly increased(P <0.05).Experiment 2: The regulatory mechanism of Artemisia ordosica on FA synthesis in the blood of cashmere goats was studied by metabolomics.The results showed that compared with CON,there were 27 differential metabolites in blood of ARI,among which Glu,phenylalanine,asparagine,and putrescine were key differential metabolites that promoted the increase of n-3PUFA such as C18:3n3 in the blood.Artemisia ordosica promoted glutathione synthesis and reduced lipid peroxidation through significantly enriched key metabolic pathways such as glutathione and phenylalanine metabolism.Promote lipolysis through pathways such as leucine and isoleucine degradation,and reduce the content of SFA such as C16:0 and C18:0 in the blood through pathways such as unsaturated fatty acid biosynthesis,fatty acid biosynthesis and degradation,and promote the deposition of C18:3n3and C20:5n3 in blood and muscle.Experiment 3 studied the regulatory mechanism of dietary addition of Artemisia ordosica on the synthesis of FA in the longest dorsal tissue of cashmere goats by transcriptomics.The results showed that compared with CON,ARI caused a total of 2433 gene changes and enriched into 324 pathways,among which Fox O signaling pathway,AMPK signaling pathway,longevity regulatory pathway,MAPK signaling pathway,adipocycykine signaling pathway,phosphatidylinositol signaling system,insulin signaling pathway,insulin resistance signaling pathway and PI3K-Akt and other pathways related to lipid metabolism were significantly enriched.CD36,AKT3,PPARGC1 A,PRKKA1 and PRKAA2 were significantly enriched into AMPK,PI3K/Akt and insulin resistance signaling pathways in DEGs with significant upregulation of Artemisia ordosica.ACSL3,ACSL4,CD36 and PPARGC1 A were significantly enriched into adipocytokine signaling pathways and insulin resistance pathways.CD36,SCP2 and other genes were enriched into the PPAR signaling pathway,and ELOVL6 and ELOVL7 were enriched into unsaturated fatty acid(UFA)biosynthesis and FA extension pathway.The significantly downregulated FASN was mainly enriched into FA biosynthesis and AMPK signaling pathways.Artemisia ordosica regulates the deposition of C18:3n3,C22:6n3 and n-3PUFA in the longest dorsal muscle through AMPK,PPAR,longevity regulatory pathway,insulin pathway and adipocycline signaling pathway.On the basis of experiment 3,Experiment 4 studied the effect of Artemisia ordosica on the activities of enzymes related to fat metabolism in albas white cashmere goat longissimus dorsi muscle.The results showed that compared with the CON group,the activities of SCD,HSL,CD36 and ELOVL5 in the longest dorsal muscle of cashmere goats were significantly increased(P<0.05)and the activity of FAS enzyme was significantly reduced(P<0.05).The activity of HSL,LPL,MDH,and blood was significantly increased(P<0.05).In summary,the addition of Artemisia ordosica to cashmere goat diets increased the contents of C18:3n3,C20:5n3,C22:6n3,PUFA,n-3LCPUFA,P/S,U/S and reduced n-6PUFA/n-3 PUFA and SFA content in muscle tissue;Key metabolic pathways,such as Glutathione and L-Phenylalanine,promoted Glutathione,reduced Lipid peroxidation,and reduced SFA levels in the blood through pathways such as fatty acid biosynthesis and degradation,promoted n-3 PUFA deposition into the muscle.The expression of CD36,SCP2 and PRKAA2 genes in the longest dorsal muscle was up-regulated by AMPK,PPAR,longevity regulatory pathway,and other pathways,and the expression of FASN gene was down-regulated.It increased the activity of lipolysis and FA uptake,transport,desaturation related enzymes and PUFA synthesis-related enzymes,reduced the activity of fatty synthesis-related enzymes,and then decreased the content of SFA,promoted the deposition of C18:3n3,C22:6n3 and n-3PUFA in the longest dorsal muscle,and improved the quality of lamb.