【作者】 黄金秀； 杨飞云； 刘作华； 周晓容； 宋凡； 刘雪芹； 叶婷；

【Author】 Huang-jinxiu,Yang-feiyun,Liu-zuohua,Zhou-xiaorong, Song-fan,Liu-xueqin,Ye-ting (Chongqing Academy of Animal Sciences,Chongqing 402460,China)

【机构】 重庆市畜牧科学院；

【摘要】 旨在研究共轭亚油酸(conjugated linoleic acid,CLA)对猪骨骼肌肌纤维类型组成的影响规律。以体外培养的原代猪骨骼肌卫星细胞为材料,在卫星细胞向肌纤维转化时添加不同水平CLA(0、50、100、150、200μg/mL),处理后第4、8和12d,分别采用相对定量RT-PCR测定肌纤维中MyHCⅠ、MyHC 2a、MyHC 2b和MyHC 2x四种MyHC的基因表达。结果表明,肌纤维类型的组成随培养时间的延长发生显著变化,从第4到12d,MyHC 2b型肌纤维比例显著上升,而其余3种类型的肌纤维比例均显著下降。添加50μg/mLCLA对肌纤维类型组成无显著影响。添加100μg/mLCLA主要影响第12d的肌纤维类型组成,而添加150～200μg/ml CLA则可显著改变第4～12d的肌纤维类型组成,即显著提高MyHCⅠ和MyHC 2a型肌纤维比例,显著降低MyHC 2x和MyHC 2b型肌纤维比例。以上结果提示,添加CLA可使肌纤维类型组成发生变化,且该作用与添加水平和处理时间密切相关。CLA对肌纤维类型组成的影响主要表现为提高MyHCⅠ和MyHC 2a型肌纤维比例,而降低MyHC 2b和MyHC 2x型肌纤维比例,这在一定程度上可解释CLA提高猪肉品质的原因。更多还原

【Abstract】 This experiment was conducted to investigate the effect of CLA on the composi- tion of myofiber types in skeletal muscle cells.The primary skeletal muscle satellite cells were used,and when the satellite cells were transformed into muscle cells,different CLA levels (0,50,100,150,200μg/mL) were added into the cells.After D4,D8 and D12 of culture, the ratios of mRNA abundance of four isoforms of myosin heavy chain(MyHC I,MyHC 2a, MyHC 2b and MyHC 2x) were determined by semi-quantitative RT-PCR.The results showed that the composition of myofiber types in skeletal muscle cells changed markedly with culture time.From D4 to D12,MyHC 2b type fiber was increased markedly,but the other three types of muscle fibers were decreased significantly.The addition of 50μg/mL CLA had no effects on the composition of myofiber types.The effects of 100μg/mL CLA on the composition of myofiber types appeared mainly on D12,while 150～200μg/mL CLA affected significantly the composition of myofiber types from D4 to D12,with an up-regulation of MyHC I and MyHC 2a type fibers,and a down-regulation of MyHC 2x and MyHC 2b type fibers.The results suggested that the composition of myofiber types in skeletal muscle cells was influenced by CLA, which depended on its dose and culture time.The effect of CLA on the composition of myofiber mainly was represented by increasing the proportions of MyHC I and MyHC 2a type fibers but decreasing the ratios of MyH 2b and MyHC 2x fibers,which could explain partially why CLA improved pork quality.更多还原