【作者】 王鑫；

【导师】 李光鹏；

【作者基本信息】 内蒙古大学 ， 动物学， 2019， 硕士

【摘要】 肌肉生长抑制素(Myostatin,MSTN)基因缺失能促进肌肉发育,提高产肉性能。为了解MSTN基因编辑在肉牛杂交改良方面的作用,本试验分析了基因编辑牛F1代杂交牛的屠宰性状和不同部位肌肉的肉质特性。结果表明,试验组与对照组牛的活体重、胴体重和屠宰率分别为646.88±58.39 kg、373.70±34.90 kg、57.76±0.01%和584.41±54.76 kg、314.40±29.04 kg、53.81±0.01%,两组之间有显著性差异(P<0.05)。与对照组相比,试验组的背最长肌亮度(Lightness,L*)和红度(Redness,a*)显著高于对照组(P<0.05);其他肉质性状如黄度(Yellowness,b*)、pH、嫩度和系水力,在上脑、眼肌、米龙和腱子部位与对照组无差异(P>0.05);试验组的背最长肌组织中,肌内脂肪含量约为5.90%,显著低于对照组(6.74%)(P<0.05),但该部位的脂肪酸组成未受到明显影响,多不饱和脂肪酸的比例略有提升。利用RNA-seq及qPCR方法对牛背最长肌组织进行基因表达检测,发现MSTN表达的下调影响了ADIPOQ、FABP4、FASN、LPL、PPARγ和SCD等与脂肪合成相关基因的表达。以上结果说明,F1代MSTN基因编辑牛的产肉性显著提高,大部分肉质特性没有发生明显改变,背最长肌肌内脂肪含量的减少与MSTN基因突变及脂肪合成相关基因表达受到抑制有潜在的关系。更多还原

【Abstract】 The inactivations of the myostatin gene in cattle often promote muscle development and improve meat production.To investigate the effect of MSTN artificial mutation on crossbreeding,carcass and meat quality traits of different parts in beef from cross-breed cattle of Luxi(MSTN^-/-)×Chinese Simmental were analyzed.The live weight and carcass weights of the two groups were 646.88±58.39kg,373.70±34.90kg and 584.41±54.76,314.40±29.04kg,respectively,as well as the dressing percentage of these cross-breeds reached to 57.76±0.01%,which was significant higher than Chinese Simmental（P<0.05）.Compared with the control group,the lightness and redness of Longissimus thoracis（LT）muscle from the MSTN mutated group were significantly higher（P<0.05）.There was no significant differences in yellowness（b*）,pH value,tenderness and water holding capacity between the two groups in the parts of high rib,ribeye,topside and shinleg（P>0.05）.The intramuscular fat contents in LT from the cross-breeds（5.90%）were significantly lower than that of the control cattle（6.74%）（P<0.05）.The fatty acid composition was not significantly affected,with the exception of the polyunsaturated fatty acids（PUFA）proportion increased in the cross-breeds slightly.The gene expressions of the LT were detected by RNA-seq and varified by qPCR.It was found that the down-regulation of MSTN gene expression affected the expression of genes related to fat synthesis such as ADIPOQ,FABP4,FASN,LPL,PPARγand SCD.It could be indicated that crossbreeding by MSTN artificial mutated cattle could increase the meat production,lead to insignificant effects on the most of meat quality.The decrease in intramuscular fat content of the LT muscle has a potential relationship with the inhibition of MSTN gene mutation and gene expression related to fat synthesis.更多还原