日粮添加乳酸菌对苏尼特羊脂质代谢及肉品质的影响

Effect of Adding Lactic Acid Bacteria in Diet on Lipid Metabolism and Meat Quality of Sunit Sheep

为探究日粮添加乳酸菌对苏尼特羊脂质代谢和肉品质的影响,选取12只3月龄苏尼特羊[体重(18.70±2.69)kg],随机均分为对照组(基础饲粮)和乳酸菌组(基础饲粮添加复合乳酸菌,复合乳酸菌活菌数为1.5×10^(9) CFU/g),进行90 d的饲养实验,对宰后苏尼特羊肉品质、血脂指标、脂肪酸组成以及脂质代谢相关调控基因的表达量进行测定。结果表明:乳酸菌组苏尼特羊背最长肌肌内脂肪含量和24 h的pH值显著高于对照组(P<0.05),L*值和蒸煮损失显著低于对照组(P<0.05)。乳酸菌组苏尼特羊血液中低密度脂蛋白胆固醇、甘油三酯含量均显著低于对照组(P<0.05);背最长肌中γ-亚麻酸、花生三烯酸、花生四烯酸、二十碳五烯酸、二十四碳烯酸含量均显著高于对照组(P<0.05)。日粮添加乳酸菌可能影响苏尼特羊血脂代谢和脂肪酸组成。与对照组相比,日粮添加乳酸菌促进了苏尼特羊脂质代谢水平,使乳酸菌组苏尼特羊背最长肌中腺苷酸活化蛋白激酶α2基因表达量显著降低(P<0.05),乙酰辅酶A羧化酶、过氧化物酶体增殖物激活受体γ、固醇调节元件结合蛋白1C的基因表达量均显著升高(P<0.05)。因此,日粮添加乳酸菌能够通过抑制腺苷酸活化蛋白激酶α2—乙酰辅酶A羧化酶信号通路,调节苏尼特羊脂质代谢。

In order to investigate the effect of adding lactic acid bacteria(LAB)in the diet on lipid metabolism and meat quality of Sunit sheep,twelve Sunit sheep aged 3 months with good body condition[body weight(18.70±2.69)kg]were selected,and then randomly divided into two groups with six sheep each.The control group was fed a basic diet,and the LAB group was supplemented with compound LAB at 1.5×10^(9) CFU/g based on the diet of the control group.The feeding period lasted for 90 d.Meat quality,blood lipid indexes,fatty acid composition and the expression of lipid metabolism genes were measured after slaughter.The results showed that compared with the control group,the addition of LAB significantly increased the content of intramuscular fat and the value of pH in 24 h(P<0.05),while significantly reduced L*and cooking loss(P<0.05)of longissimus dorsi muscle.The analysis of serum lipid metabolism showed that the dietary supplementation with the LAB decreased the low-density lipoprotein cholesterol and triglyceride of Sunit sheep(P<0.05).The contents ofγ-linolenic acid,eicosatrienoic acid,arachidonic acid,eicosapentaenoic acid and eicosatetraenoic acid in the LAB group were significantly higher than the control group(P<0.05).Dietary supplementation of LAB could affect lipid-related indexes and fatty acid composition of Sunit sheep.Furthermore,the addition of LAB to the diet significantly inhibited the expression of AMP-activated protein kinaseα2 gene in the longissimus dorsi muscle of Sunit sheep(P<0.05),and promoted the expression of acetyl-coa carboxylase,peroxisome proliferator-activated receptorγand sterol regulatory element binding protein-1C(P<0.05).Therefore,dietary supplementation of LAB could regulate lipid metabolism in Sunit sheep through inhibiting AMP-activated protein kinaseα2-acetyl-coa carboxylase signaling pathway.