HMBi对肉牛肉品质、血清生化指标和肌肉组织H-FABP基因mRNA表达水平的影响

The effect of HMBi on carcass characteristics,serum biochemical indexes,intramuscular fat content and the H-FABP gene mRNA expression in beef cattle

选择平均年龄4-5岁、体重相近的徐州黄牛16头进行配对,随机分为对照组和试验组,每组8头,在相同的条件下饲养.试验组分别在每头肉牛的精料中添加8 g·d-1蛋氨酸羟基类似物异丙醇酯(HMBi),对照组的精料不添加HMBi.试验结束后统一屠宰,并测定相关指标,研究HMBi对肉牛胴体品质、血清生化指标、肌内脂肪含量以及心脏型脂肪酸结合蛋白(H-FABP)基因mRNA表达水平的影响.结果表明:在肉牛胴体品质方面,与对照组相比,试验组肉牛的肌肉色、脂肪色、剪切力和蒸煮损失均无显著差异(P>0.05);但大理石花纹等级高于对照组(P>0.05).在血清生化指标方面,试验组肉牛血清的甘油三酯含量在试验后极显著低于对照组(P<0.01);尿素氮浓度在试验后较试验前极显著降低(P<0.01),且试验期间试验组低于对照组(P>0.05);试验组葡萄糖浓度高于对照组(P>0.05),而脂肪酶活性,高密度脂蛋白胆固醇、低密度脂蛋白胆固醇和总胆固醇浓度则无显著变化(P>0.05).试验组肉牛背最长肌和臀中肌的肌内脂肪含量高于对照组(P>0.05).试验组肉牛背最长肌H-FABP基因mRNA的表达量高于对照组(P>0.05).可见,在日粮精料中添加8 g·d-1HMBi能降低肉血清甘油三酯水平,有提高大理石花纹等级的趋势,对肌内脂肪含量以及背最长肌H-FABP基因mRNA的表达量无显著影响.

Sixteen Xuzhou cattle （average age 4-5 year old） were selected and randomly divided into control group and treatment group with eight head in each group,according to the principles of same age and body weight.Control group were fed with a based diet [0 g 2-hydroxy-4-（methylthio） butanoic acid isopropyl ester （HMBi）] while treatment group were supplemented with 8 g · d^-1 HMBi per head.Related indicators were tested after slaughter,to evaluate the effects of HMBi on carcass characteristics,serum biochemical indexes,intramuscular fat content and the heart fat acid binding protein （H-FABP） gene expression in finishing cattle.Result showed that compared with control group,the meat color,fat color,shearing-force and cooking-loss had no significant change （P 〉 0.05） ; but marbling scores were higher than that in control group （P 〉 0.05）.The concentrations of serum triglycerides were significantly lower than that of control group （P 〈 0.05）.The concentrations of blood urea nitrogen in the two groups significantly decreased after the experiment （P 〈 0.05）,and the treatment group were higher than the control group （P 〉 0.05）.The serum glucose in treatment group was also higher than that in control group （P 〉0.05）.HMBi supplementation in finishing cattle had no significant effects on lipase,high-density lipoprotein cholesterol,low-density lipoprotein cholesterol and total cholesterol （P 〉 0.05）.The intramuscular fat and the H-FABP gene expression in longissimus dorsi and gluteus medius were higher than that in control （P 〉 0.05）.It is concluded that HMBi supplementation in finishing cattle can decrease the content of serum triglycerides,has a tendency to improve the marbling score of beef,has no significant effects on the intramuscular fat and H-FABP mRNA gene expression.