【摘要】 旨在研究低蛋白日粮对山羊胴体品质和肌肉氨基酸与脂肪酸组成以及肌源性调节因子基因表达的影响。选取24头生长期湘东黑山羊母羊，随机分为正常蛋白日粮组(CON组，CP:10.77%,n=12)与低蛋白日粮组(LP组，CP:5.52%,n=12),预试期25 d,正试期45 d。结果表明，LP组肌肉屠宰后24 h的肉色L~*值显著升高，而肌肉pH值和失水率等无显著差异；骨骼肌Ⅰ型、Ⅱ型肌纤维比例无显著差异，仅LP组半腱肌肌纤维总平均横截面积呈现降低的趋势；LP组股外侧肌中缬氨酸、亮氨酸、赖氨酸、苯丙氨酸、谷氨酸及总必需氨基酸的含量显著降低，异亮氨酸、蛋氨酸、天冬氨酸、精氨酸和总氨基酸含量呈现下降趋势；半腱肌中谷氨酸的含量显著降低，苏氨酸和丝氨酸的含量呈现下降趋势；LP组半腱肌中二十碳二烯酸和二十二烯酸的含量显著降低；外侧肌中总多不饱和脂肪酸、油酸、花生四烯酸的含量显著降低；背最长肌中油酸的含量显著降低；LP组半腱肌MYOD基因表达显著下调。综上表明，饲喂低蛋白日粮不影响肌纤维类型的转化与横截面积；日粮蛋白质缺乏会降低骨骼肌中氨基酸的沉积，同时减少肌肉多不饱和脂肪酸的沉积，影响山羊肌肉风味。更多还原

【Abstract】 The aim of this study was to investigate the effects of low protein diet on meat quality, amino acid and fatty acid composition of skeletal muscle and blood, and mRNA expression of myogenic regulatary factor genes of black goat.A total of 24 female Xiangdong black goats were randomly divided into control group(CON,10.77% CP,n=12)and low protein group(LP,5.52% CP,n=12).The pre and post-trial lasted for 25 d and 45 d, respectively.The results were as follows: Low protein diet increased L~* 24 h of meat color, but had no difference on pH value and water loss rate.The percentage of type Ⅰ muscle fiber and type Ⅱ muscle fiber had no difference between two groups, only the average fiber cross sectional areas of semitendinosus had a tendency to reduce.Valine, leucine, lysine, phenylalanine, glutamate and total essential amino acids of vastus lateralis significantly reduced, isoleucine, methionine, aspartate, arginine and total amino acid tended to decrease.Glutamate of semitendinosus in the LP group significantly reduced, threonine and serine tended to decrease.Compared with the control group, C20∶2 and C22∶1 n9 of semitendinosus in the LP group significantly decreased.Total PUFA,C18∶1 n9 c, and C20∶4 n6 of vastus lateralis in the LP group significantly decreased; C18∶1 n9 c of longissimus dorsi in the LP group significantly decreased.Compared with the control group, the mRNA expression of MYOD in semitendinosus were significantly down-regulated in the CON group.In conclusion, low protein diet didn′t affect type conversion and cross sectional area of muscle fiber.Dietary protein deficiency reduced the deposition of amino acid in muscle, while reduced the deposition of polyunsaturated fatty acids in muscle, which affected on muscle flavor of goat.更多还原