摘要:
[Objective] This study aimed to investigate the effects of mulberry on blood lipid and expression of lipoprotein lipase (LPL),fatty acid synthase (FASN),and Leptin genes in Cashmere goat.[Method] Sixty healthy Cashmere goats (with average weight of (28± 1.05) kg) were randomly divided into six groups with ten goats in each group.The goats in the six groups were fed with basal diet (control group),basal diet containing 10% and 15% dried mulberry (dry mulberry groups Ⅰ and Ⅱ),and basal diet containing 10%,15% and 20% silage mulberry (silage mulberry groups Ⅰ,Ⅱ and Ⅲ).The experiment las ted for 70 days.At the end of feeding experiment,three goats were randomly selected and slaughtered in each group.Blood samples were collected through neck vein and serum was separated before slaughter.The samples of subcutaneous fat,perirenal fat,tail fat,liver and longissimus muscle were also collected after slaughter for analyzing expression of LPL,FASN and Leptin by real-time quantitative PCR.[Result]Compared with control group,the serum LDL-C concentrations in dry mulberry group Ⅱ and silage mulberry group Ⅱ were significantly decreased by 36.4% and 30%,respectively (P<0.05).The concentrations of Leptin in dry mulberry groups were significantly decreased (P<0.05) and the concentrations of FASN were significantly decreased in dry mulberry group Ⅱ (P<0.05) and silage mulberry group Ⅲ (P< 0.05).The expressions of LPL,FASN and Leptin had tissue expression specificity.The effect of supple mentation mulberry on gene expression of Cashmere goat was different.In liver,the expression of FASN significantly was decreased in dry mulberry group Ⅱ and silage mulberry group Ⅱ (P<0.05).In subcutaneous fat,the expression of LPL and Leptin in silage mulberry group Ⅲ was significantly higher than in the control group (P<0.05).In perirenal fat,the expression of LPL increased significantly in silage mulberry group Ⅱ (P<0.05).In tail fat,the expression of LPL in dry mulberry group Ⅱ and silage mulberry group Ⅱ was significantly increased (P<0.05),and the expression of Leptin in dry mulberry group Ⅱ and silage mulberry group Ⅲ were significantly increased (P<0.05).In longissimus muscle,the expression of LPL and Leptin was significantly increased in silage mulberry group Ⅱ (P<0.05).[Conclusion] The supplementation of dry mulberry or silage mulberry had regulation effect on fat metabolism of Cashmere goats,and the effect of silage mulberry was more significant in the whole.The supplementation of 15% silage mulberry had good effect of lowering blood fat,lowering blood TC,TG and LDL-C concentrations,promoting expression of LPL and Leptin in adipose tissue,and inhibiting the expression of FASN in liver.%[目的]探讨日粮中桑叶添加方式和添加量对绒山羊血脂代谢及组织中脂蛋白酯酶(LPL)、脂肪酸合成酶(FASN)、瘦素(Leptin)基因表达量的影响.[方法]选用体况良好(平均体质量(28±1.05) kg/只)的陕北白绒山羊羯羊60只,随机均分为对照组、干桑叶组Ⅰ、干桑叶组Ⅱ、青贮桑叶组Ⅰ、青贮桑叶组Ⅱ、青贮桑叶组Ⅲ6组,其中对照组日粮中不添加桑叶;干桑叶组Ⅰ、Ⅱ日粮中分别添加质量分数10%,15%的自然风干桑叶,青贮桑叶组Ⅰ、Ⅱ、Ⅲ组日粮中分别添加质量分数10%,15%,20%的青贮桑叶.饲养试验持续70 d.饲养试验结束后,每组随机挑选3只羊进行屠宰,宰前颈静脉采血并分离血清,宰后采集腹部皮下脂肪、肾周脂肪、尾部脂肪、肝脏、背最长肌组织样.测定血清中血脂代谢相关指标;通过实时荧光定量PCR检测各组织中LPL、FASN、Leptin基因表达量.[结果]干桑叶组Ⅱ和青贮桑叶组Ⅱ的血清LDL C浓度分别显著降低36.4%和30%(P<0.05);饲喂干桑叶组羊血清Leptin质量浓度显著降低(P<0.05);干桑叶组Ⅱ和青贮桑叶组Ⅲ中血清FASN质量浓度均显著降低(P<0.05).LPL、FASN、Leptin具有组织表达特异性,且日粮中添加桑叶对绒山羊各组织中基因表达的影响不同.肝脏中,干桑叶组Ⅱ和青贮桑叶组Ⅱ中FASN基因表达量显著降低(P<0.05);腹部皮下脂肪中,青贮桑叶组Ⅲ的LPL、Leptin基因表达量显著增加(P<0.05);肾周脂肪中,LPL基因表达量在青贮桑叶组Ⅱ中显著上升(P<0.05);尾部脂肪中,干桑叶组Ⅱ和青贮桑叶组Ⅱ的LPL基因表达量显著增加(P<0.05),干桑叶组Ⅱ和青贮桑叶组Ⅲ的Leptin表达量显著增加(P<0.05);背最长肌中,青贮桑叶组Ⅱ的LPL、Leptin基因表达量显著上升(P<0.05).[结论]日粮中添加干桑叶和青贮桑叶对绒山羊脂肪代谢均有调控作用,但整体上饲喂青贮桑叶效果更显著;在日粮中添加质量分数15%的青贮桑叶有更好的降血脂效果,降低血液中TC、TG、LDL-C浓度,促进脂肪组织中LPL、Leptin基因表达,抑制肝脏中FASN基因表达.