Effects Of Allium Mongolicum Regel Extracts On Metabolism Of 4-alkyl Branched-Chain Fatty Acids Of Body Fat And Its Mechanism In Lambs

The objective of this study was to determine the effects of Allium Mongolicum Regel(AMR)extracts on metabolism of 4-alkyl branched-chain fatty acids of body fat and its mechanism in lambs.The effects of AMR extracts on the deposition of 4-alkyl branched fatty acids[4-methyloctanoic acid(MOA),4-methylnonanoic acid(MNA)and 4-ethyloctanoic acid(EOA)]were studied by animal feeding and slaughter experiments.The deposition,distribution,and candidate gene expression of 4-alkyl branched fatty acids were detected of body fat in small-tailed Han sheep,and then the samples with high and low characteristic flavor and odor level were screened out.The biological information of differentially expressed proteins was analyzed in high and low characteristic flavor and odor groups through proteomics and metabolomics,and finally the mechanism of removing characteristic flavor and odor of AMR extracts was analyzed by the joint analysis of proteomics and metabolomics.This study mainly involved in five experiments:The aim of experiment 1 was to investigate the effect of dietary supplementation of AMR extracts on deposition and distribution of 4-alkyl branched-fatty acids of types of adipose tissue in lambs.Sixty 3-monty-old male small-tailed Han sheep(average body weight,23.67±3.43 kg)were selected and randomly allocated into four groups in a randomized block design.Four feeding regimes were used:1)basal diet without supplementation as control groups(CK);2)basal diet supplemented with 10 g-lamb-1·d AMR powder as AMR group(AMR);3)basal diet supplemented with 3.4 g·lamb-1·d AMR water-soluble extract as AWE group(AWE);4)basal diet supplemented with 2.8 g-lamb-1-· AMR ethanol-soluble extract as AFE group(AFE).Experiment lasted for 75 days,including a 15-day preliminary feeding period for adaptation and a 60-day experimental feeding period.At the end of the feeding experiment,six lambs per group were harvested after an 18 hour fast.Perirenal adipose tissue(PF)weight,dorsal subcutaneous adipose tissue(DF),tail adipose tissue(TF),and greater omental adipose tissue(GF)samples were wrapped in aluminium foil,vacuum-packed in sealable polyamide bags,snap frozen in liquids N2 and stored at-80℃ until 4-alkyl branched-fatty acids analysis.The experiment results showed that:(1)Dietary supplementation with AMR and its extract could reduce the concentrations of three branched-chain fat acids of DF,PF,and GF to a different extent,and AMR ethanol-soluble extract could significantly reduce the characteristic flavor and odor,yet has no significant effect on of three branched-chain fatty acids deposition in TF.(2)The concentration of MOA in DF was closely related to the EOA concentrations,but weaker correlation existed between MOA and MNA,EOA,and MNA.The concentrations of MOA and MNA,EOA,and MNA had no significant correlation in GF,although there was a tendency correlation for concentrations of MOA and EOA.The concentrations of MOA in PF were closely related to the EOA concentrations and the MNA concentrations,but weaker correlation existed between EOA and MNA.The aim of experiment 2 was to investigate the effect of AMR and its extracts on the expression of candidate genes for the synthesis of 4-alkyl branched-fatty acids in lambs.Experiment design and sample collection are the same as experiment 1.Based on the results of experiment 1,the AMR ethanol-soluble extract group was determined to be low lamb odor and flavor(LOF)level group.The control group was the high LOF level group.The experiment results showed that:(1)The expression of candidate genes of characteristic flavor and odor substance in adipose tissue has tissue specificity.(2)The order of the expressions of candidate genes of lamb odor and flavor in types adipose tissue was TF>DF>GF>PF,which is consistent with the deposition rule of branched-chain fatty acids(MOA,MNA and EOA)in different adipose tissue.(3)In addition to TF,the expressions of JAML,SULT1C1,UDPGT2B18,and GSTM1 were positively correlated with the total deposition of branched-chain fatty acids in PF,DF and GF,while the expressions of KIF12 was negatively correlated with the total deposition of branched-chain fatty acids.The aim of experiment 3 was to investigate the effect of AMR extracts on proteomic characteristics of adipose tissue at different LOF levels.Based on the results of experiments 1 and 2,we selected the PF of AMR ethanol-soluble extract as the low LOF group,and the PF of the control group as the high LOF group.We identified the expression of different proteins in high and low LOF levels by the quantitative proteomic technology of TMT(tandem mass tag),and analyzed the biological information of different proteins.The experiment results showed that:(1)The related pathway of AMR ethanol-soluble extract reducing 4-alkyl branched fatty acids of PF in lambs is metabolism of xenobiotics by cytochrome P450,Drug metabolism-cytochrome P450,Tyrosine metabolism,Phenylalanine,tyrosine and tryptophan biosynthesis and Steroid hormone biosynthesis.(2)Maybe up-regulated(leucine and crystal aminopeptidase,membrane metalloendopeptidase,and cathepsin F)and down-regulated(serine hydroxymethyltransferase,ornithine carbamoyltransferase,glutathione S-transferase ξ1,phenylalanine hydroxylase,glucosyltransferase,corticosteroid 11β dehydrogenase isoenzyme 1 and sulfotransferase)and other related proteins regulate of 4-alkyl branched fatty acid metabolism.The aim of experiment 4 was to investigate the effect of AMR extracts on metabolomic characteristics of adipose tissue at different LOF levels.We selected the PF of AMR ethanol-soluble extract as the low LOF group,and the PF of the control group as the high LOF group.We identified the expression of different metabolites in high and low LOF levels by the quantitative proteomic technology of LC-MS non targeted metabonomics,and analyzed the biological information of different proteins.The experiment results showed that:the AMR ethanol-soluble extract can reduce the synthesis and deposition of 4-alkyl branched fatty acids of PF in lambs,mainly through the histidine metabolism pathway,glycerophospholipid metabolism pathway,arginine and proline metabolism pathway,linoleic acid metabolic pathway.The aim of experiment 5 was to investigate the mechanism of removing characteristic flavor and odor of AMR extracts by the joint analysis of proteomics and metabolomics.The experiment results showed that:proteomics and metabolomics combined analysis found that the metabolic pathways involved in differential expression of protein and differential metabolites were amino acid metabolic pathway,fatty acid metabolic pathway,exogenous material metabolic pathway,and disease-related pathway.AMR ethanol-soluble extract mainly affects the above four metabolic pathways,and then through regulating the expression of differential proteins and metabolites,it can reduce the deposition of 4-alkyl branched-chain fatty acids of perirenal adipose tissue in small-tailed Han sheep.In conclusion,AMR and its extracts have a positive effect on the reduction of characteristic flavor and odor of body fat in lambs,except for tail adipose tissue.AMR and its extracts can affect the expression of candidate genes of s characteristic flavor and odor of body fat.The results of proteomics and metabolomics combined analysis showed that AMR ethanol-soluble extract affected amino acid metabolism pathway,fatty acid metabolism pathway,exogenous substance metabolism pathway,and disease-related pathway through regulating the expression of differential proteins and metabolites,and then reduced the deposition of 4-alkyl branched fatty acids of perirenal adipose tissue in small-tailed Han sheep,to achieve the effect of eliminating characteristic flavor and odor.