猪背最长肌肌纤维类型的发育性变化及品种与营养影响特点  

Developmental Changes of Myofiber Types in Longissimus Dorsi Muscle of Rongchang and DLY Pigs under Different Nutrient Condition

作　　者：杨飞云[1,2] 陈代文[1] 黄金秀[2] 刘作华[2] 

机构地区：[1]四川农业大学动物营养研究所,雅安625014 [2]重庆市畜牧科学院,重庆402460

出　　处：《畜牧兽医学报》2008年第12期1701-1708,共8页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：国家973项目(2004CB117503);重庆市自然科学基金重点项目(2005BA10122008BA1013)

摘　　要：选用荣昌（RC）猪和杜×长×大（DLY）杂交猪为试验动物，采用相对定量RTPCR测定10～120kg体质量时背最长肌中I、2a、2x和2b4种MyHC的基因表达，以探讨猪背最长肌肌纤维类型的发育性变化，并分析品种及营养对它的影响特点。结果表明：（1）10～20始，2个品种的背最长肌肌纤维类型的百分组成发生显著改变，MyHCI和2x型纤维比例显著降低，而2b型纤维比例显著提高；（2）20～120kg，背最长肌肌纤维的变化规律因品种和纤维类型而异，除MyHC2b外，2个品种的MyHCI、2a和2x型肌纤维的发育规律存在一定差异；（3）背最长肌肌纤维类型的百分组成在10～50kg阶段未见品种间显著差异，但在80kg，RC猪的MyHC2b型纤维比例显著低于DLY猪，而2a型纤维比例则正好相反；（4）饲粮营养水平对2个品种猪背最长肌肌纤维类型的百分组成均无显著影响。以上结果提示，2个品种的背最长肌肌纤维类型的发育性规律及组成存在差异，且纤维组成差异主要表现在80kg，RC猪的MyHC2b型纤维比例显著低于DLY猪，可能与其优良肉质相关。This experiment was conducted to study the developmental changes of myofiber types in longissimus dorsi （LD） muscle of Rongchang （RC） and Duroc× Landrace×Yorkshire （DLY） pigs under different dietary nutrient condition, by determining the proportion of mRNA abundance of four isoforms of myosin heavy chain （MyHC I, 2b, 2b and 2x） with semi-quantitative RT-PCR. The results showed that： （1）From 10 to 20 kg BW, the composition of myofiber types in LD muscle of both breeds changed dramatically with significantly decreased MyHC I and 2x fibers but ramarkably increased MyHC 2b fiber. （2） From 20 to 120 kg BW, the developmental changes of myofibers in LD muscle varied in breed and myofiber type. Except MyHC 2b fiber, the developmental patterns of the other three myofiber types were different between the two breeds. （3）There was no difference in the proportion of four myofiber types in LD muscle during 10-50 kg BW between the two breeds, but at 80 kg BW, RC pigs showed significantly lower proportion of MyHC 2b fiber and higher proportion of MyHC 2a fiber compared with DLY pigs. （4）Dietary nutitional levels had no significant effect on the composition of myofiber types in LD muscle of both breeds. The results suggested that the developmental changes and composition of myofiber types in LD muscle varied in breed. The breed difference of the composition appeared at 80 kg, and RC pigs showed significantly lower proportion of MyHC 2b fiber, which might correspond to their better meat quality.

关 键 词：猪 背最长肌 MYHC I MYHC 2a MYHC 2b MYHC 2x 

分 类 号：S828[农业科学—畜牧学] S852.16[农业科学—畜牧兽医]