| This study was conducted to investigate the effects of Allium Mongolicum Regel(AMR)and its extracts on the lipid metabolism and composition of volatile flavor compounds and its relevant mechanism in Mutton Sheep,to provide a scientific basis for the production of high-quality mutton using AMR and its extracts as a natural feed additive.Forty healthy wether Small-tail han sheep with 5 to 6 month old and weight about 35 kg were randomly divided into four groups with 10 sheep per group,namely the control group and three experimental groups(polysaccharide group,AMR group and filter residue group).Sheep in the control group were fed with basal diet,and sheep in the polysaccharide group,AMR group and filter residue group were fed with 0.1%AMR polysaccharide,10 g AMR daily per sheep and 10 g filter residue daily per sheep based on basic diet,respectively.The experiment lasted for 75 days,which included 15 days for preliminary experiment and 60 days for the formal experiment.At the beginning and end of the formal experiment,all the sheep were weighed and blood samples were collected on an empty stomach.At the end of the experiment,six sheep from each group were randomly slaughtered,and longissimus dorsi muscle,gluteus muscle and subcutaneous fat were collected.In the first experiment,the effects of AMR and its extracts on the growth performance and lipid metabolism related blood indices of mutton sheep were studied.The results showed that compared with the control group,the average daily feed intake(ADFI)and average daily gain(ADG)showed an increasing trend and feed to gain ratio(F/G)had a decreasing trend in three experimental groups;the contents of triglyceride(TG),low-density lipoprotein cholesterol(LDL-C)and glucose(GLU)of serum in three experimental groups were not changed(P>0.05),while the contents of total cholesterol(TC)and high-density lipoprotein cholesterol(HDL-C)of serum in polysaccharide group were significantly increased(P?0.05),the serum contents of growth hormone(GH)were increased in three experimental groups,among which that in filter residue group was increased significantly(P?0.05),in addition,the serum contents of leptin(LEP)were significantly increased in three experimental groups(P?0.05).In the second experiment,the effects of AMR and its extracts on the composition and content of fatty acids in mutton sheep were determined.The results showed that on the basis of total fatty acids,compared with the control group,the contents of midchain mutton odour fatty acid(MCMOFA),C14:1,C16:1 and C17:1 of longissimus dorsi muscle in AMR group,the contents of C22:6n3 of gluteus muscle in three experimental groups,the content of C20:2 of gluteus muscle in polysaccharide group,the content of C18:1n9c of subcutaneous fat in AMR group,the content of C18:3n3 of subcutaneous fat in filter residue group and the contents of C18:3n6 of subcutaneous fat in AMR and polysaccharide group were significantly decreased(P<0.05),the contents of C10:0,C23:0 and MCMOFA of gluteus muscle in filter residue group,the contents of C20:0 of the gluteus muscle in AMR group and filter residue group,the contents of C20:1 and C18:3n6 of gluteus muscle in AMR group,the contents of C17:0 of subcutaneous fat in AMR and filter residue group,the contents of C18:0 and C18:1n9t of the subcutaneous fat in AMR group and C15:1 of subcutaneous fat in three groups were significantly increased(P?0.05);On the basis of fresh meat,compared with the control group,the contents of most fatty acids of diffrent parts in three experimental groups were reduced to varying degrees,the contents of saturated fatty acid(SFA),MCMOFA,C8:0,C10:0,C12:0,C13:0,C14:0,C15:0,C16:0,C18:0,C22:0,C14:1,C17:1,C22:1n9,C18:2n6c and C18:3n6 of longissimus dorsi muscle in AMR group,the contents of C13:0,C18:2n6c and C20:2 of longissimus dorsi muscle in polysaccharide group,the contents of C18:0 of longissimus dorsi muscle in filter residue group,the contents of polyunsaturated fatty acid(PUFA),C20:3n3,C20:4n6 and C20:5n3 of longissimus dorsi muscle in three experimental groups,the contents of C21:0,C20:2,C20:4n6 and C22:6n3 of gluteus muscle in polysaccharide group,the contents of C20:3n3,C20:4n6 and C22:6n3 of gluteus muscle in AMR group,the contents of PUFA,C18:2n6c,C20:2,C20:3n3,C20:4n6 and C22:6n3 of gluteus muscle in filter residue group,the contents of SFA,C14:0,C16:0,MUFA,C18:ln9c,unsaturated fatty acid(UFA)and total fatty acid(TFA)of subcutaneous fat in AMR group,the contents of C18:3n3 of subcutaneous fat in AMR and filter residue group and the contents of C18:3n6 of subcutaneous fat in polysaccharide and AMR group were significantly decreased(P?0.05),the contents of C15:1 of subcutaneous fat in three experimental group were significantly increased(P?0.05);compared with the control group,the PUFA to SFA ratio(P/S)of longissimus dorsi muscle and gluteus muscle in polysaccharide group and that of gluteus muscle in filter residue group were significantly decreased(P?0.05),besides,the atherogenic index(AI)of gluteus muscle in filter residue group was significantly increased(P?0.05),while the AI of longissimus dorsi muscle,gluteus muscle and subcutaneous fat in polysaccharide and AMR groups,and the thrombosis index(TI)of longissimus dorsi muscle in polysaccharide and filter residue groups were decreased(P>0.05).In the third experiment,the effects of AMR and its extracts on the composition of volatile flavor compounds were examined.The results showed that most of the volatile flavor compounds of the longissimus dorsi muscle and gluteus muscle in mutton sheep were aldehydes,acids and alcohols,of which the varieties and contents of aldehydes are the most;compared with the control group,The composition of volatile flavor of the longissimus dorsi muscle and gluteus muscle in three experimental groups was changed,the varieties of volatile flavor compounds and aldehydes were reduced in treatment groups,the contents of aldehydes of the longissimus dorsi muscle and gluteus muscle in three experimental groups were reduced to some extent,and the contents of aldehydes of longissimus dorsi muscle in AMR group and of gluteus muscle in three experimental groups were decreased significantly(P?0.05),and the changes in the varieties of the total volatile flavors compounds and aldehydes as well as the contents of aldehydes were consistent with changes in PUFA contents.In the forth experiment,the effects of AMR and its extracts on genes related to lipid metabolism were detected.The results showed that the mRNA expression of DGAT1,FADS2,FABP4,CEBPA and SREBF1 of longissimus dorsi muscle in polysaccharide group,the mRNA expression of ACACA,SCD,FABP4 and CEBPA of longissimus dorsi muscle in AMR group,the mRNA expression of DGATI,ACACA,FAS,SCD,FADS2,ELOVL5,FABP4,FABP3,PPARG,CEBPA and SREBF1 of longissimus dorsi muscle in filter residue group,the mRNA expression of LPL and FABP3 of gluteus muscle in filter residue group,the mRNA expression of DGAT1,ACACA,FADS1,FADS2,LPL,FABP4,PPARG,CEBPA,CEBPB,HSL and PPARA of subcutaneous fat in polysaccharide group,the mRNA expression of DGAT1,FADS1,FADS2,CEBPB and PRKAA2 of subcutaneous fat in AMR group and the mRNA expression of FABP3 of subcutaneous fat in filter residue group were significantly decreased(P?0.05),while the mRNA expression of HSL of longissimus dorsi muscle in polysaccharide group,the mRNA expression of CPT1B of longissimus dorsi muscle and ELOVL6 and PPARG of gluteus muscle in AMR were significantly up-regulated(P<0.05).In summary,the AMR and its extracts could regulate the fatty acid composition and content,composition of volatile flavor compounds and genes related to lipid metabolism in different parts of mutton sheep to affect the nutritional value and flavor of mutton.The reduction of PUFA contents lead to reduced types of total volatile flavor compounds as well as tpes and contents of aldehydes.Moreover,the expression of genes related to lipid metabolism and serum hormones jointly regulated the lipid metabolism of mutton sheep. |
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