| The objectives of this study were to investigate the effects of dietary supplementation of SCD inhibitor(phoenix tree seed oil)and accelerator(rosiglitazone)on the fat metabolism,and the composition and content of functional fatty acids such as oleic acid(CLA)in sheep tissues.The results will provide a theoretical basis for revealing the endogenous production pathway of CLA in sheep tissues.Eighteen crossbreed ram(Merino sheep? × thin-tail Han sheep?),similar in body weight(27.71±2.64)kg and body condition,were randomly divided into 3 groups with 6 sheep per group for single-pen(2.0 m long ×1.2 m width)feeding.The dietary design corresponding to each group is as follows:1)sheep in control group(C group)were fed a basal diet +4.8% linseeds;2)those in phoenix tree seed oil group(W group)were fed the C group diets supplemented with 15 g/d phoenix tree seed oil;those in rosiglitazone group(L group)were fed the C group diets supplemented with 8 mg/d rosiglitazone.The trial period lasted for 50 d consisting 10 d of transition period,5 d of pretrial period and 35 d of trial period.The present study consists of four trials:Trial I: Effect of dietary supplementation of phoenix tree seed oil and rosiglitazone on the performance and slaughter performance of sheep.The results showed as follows: the addition of phoenix tree seed oil and rosiglitazone in diets had no significant effects on production performance,slaughter performance and meat productivity(P>0.05);about adipose deposition,backfat thickness in W group was significantly higher than that in C group and L group by 12.55% and 17.23%,respectively(P<0.05).Trial II: Effect of dietary supplementation of phoenix tree seed oil and rosiglitazone on lipid metabolism related hormone,biochemical index and enzyme activity of sheep.The results showed as follows:1)for serum hormone indexes,serum contents of growth hormone(GH),glucagon(GC)and leptin(LEP)in W group were significantly higher than those in C group(P<0.05),and serum GC content in L group was significantly higher than that in C group(P<0.05);2)for serum biochemical indexes,compared with C group,serum contents of high density lipoprotein cholesferol(HDL-C),low density lipoprotein cholesferol(LDL-C),total cholesterol(TC)and triglyceride(TG)were significantly increased in W group(P<0.05),but only serum TG content was significantly increased in L group(P<0.05);3)for serum activity indexes,compared with C group,the activity of fatty acid synthase(FAS),lipoprotein esterase(LPL)and acetyl-CoA carboxylase(ACC)in W group were significantly increased(P<0.05),and the activity of stearyl-Co A desaturase(SCD)was significantly decreased(P<0.05),the activity of FAS,LPL,ACC and SCD in L group were significantly increased(P<0.05).Trial III: Effect of dietary supplementation of phoenix tree seed oil and rosiglitazone on lipid metabolism related enzyme activity and gene expression of sheep tissues.The results showed as follows:1)for enzyme activity of tissues,compared with C group,the W group inhibited the activities of longissimus muscle ACC and SCD in sheep(P<0.05),but had no effect on the activities of ACC,FAS,LPL and SCD in subcutaneous fat;compared with C group,the L group significantly increased the enzyme activity of longissimus muscle LPL,SCD and subcutaneous fat FAS(P<0.05)in sheep while had no effect on the activity of ACC enzymes in the longissimus muscle and subcutaneous fat;2)for enzyme gene relative expression of tissues,compared with C group,the expression of PPAR-? mRNA in the longissimus muscle and subcutaneous adipose of animals in W group were increased by 42% and 28%,respectively;the expression of SREBP-1 and SCD mRNA in the longissimus muscle were decreased by 20% and 24% respectively(P<0.05);compared with C group,the mRNA expression levels of PPAR-? and SREBP-1 in the longissimus muscle of animals in L group were significantly increased by 93% and 35%,respectively(P<0.05),the expression of FAS,LPL and SCD mRNA were increased 36%,56% and 22%,respectively(P<0.05),and the expression of PPAR-? and FAS mRNA in subcutaneous adipose of animals in L group were significantly increased by 25% and 32%,respectively(P<0.05).Trial IV: Effect of dietary supplementation of phoenix tree seed oil and rosiglitazone on meat quality and fatty acid composition and content in tissues of longissimus muscle of sheep.The results showed as follows:1)for meat quality indexes,the addition of phoenix tree seed oil and rosiglitazone in diets had no significant effects on meat quality of longissimus muscle in sheep(P>0.05);2)for fatty acid composition and content indexes,compared to animals in C group,the contents of trans-11 C18:1 and trans-9,12 C18:2 were significantly increased for animals in W group,and the contents of C18:3(n-6)in the longissimus muscle was decreased(P<0.05),the contents of C20:1 in subcutaneous adipose was increased(P<0.05)for animals in W group,while had no significant effects on other fatty acids;compared to animals in C group,animals in L group had significantly higher contents of trans-11 C18:1,trans-9,12 C18:2,cis-9,trans-11 CLA,PUFA and PUFA/SFA,and had lower contents of C18:3(n-6)and SFA in the longissimus muscle(P<0.05),and had significantly higher contents of C10:0,cis-9 C18:1 and C20:3(n-3)in subcutaneous adipose(P<0.05). |
PDF Full Text Request