This study evaluated the effects of bran fiber levels on carcass traits, meat quality and expression of myosin heavy chain isoform genes in muscles in Erhualian (Er-HL) and Large White pig (LW). Our results showed that fiber level did not affect carcass weight of Er-HL, while carcass weight of LW decreased with the increase of fiber level. Fiber level did not influence meat quality traits of LW, whereas increased fiber level led to an increase in pH_{45 min} of Er-HL, and Er-HL fed 7% bran fiber (BRC) increased redness of meat compared with control diet (CON). We observed a decreased MyHCIIb and MyHCIIx mRNAs and protein levels in Er-HL fed 7% BRC compared with those in other groups, accompanying with a tendency for increased mRNA abundance of MyHCI. The slow-twitch oxidative fiber (MyHCI) is rich in myoglobin and mitochondrial oxidative metabolic enzymes, and the increased expression of MyHCI fiber in pork has resulted in higher redness value. In summary, bran fiber had no adverse effect on the meat quality of LW and appropriate fiber level addition in diets could improve meat quality of Er-HL through regulation the expression of myofiber types.

这项研究评估了麸皮纤维水平对二化lian（Er-HL）和大型白猪（LW）的car体性状，肉品质和肌球蛋白重链同工型基因表达的影响。我们的结果表明，纤维水平不影响Er-HL的car体重量，而LW的car体重量随纤维水平的增加而降低。纤维水平不影响LW的肉质特性，而增加纤维水平导致Er-HL的pH _{45 min}升高，与对照饮食相比，添加7％麸皮纤维（BRC）的Er-HL增加了肉的发红）。我们观察到饲喂7％BRC的Er-HL的MyHCIIb和MyHCIIx mRNA和蛋白水平与其他组相比有所降低，并伴有MyHCI mRNA丰度增加的趋势。慢抽动氧化纤维（MyHCI）富含肌红蛋白和线粒体氧化代谢酶，猪肉中MyHCI纤维表达的增加导致较高的发红值。综上所述，麸皮纤维对LW的肉质没有不良影响，日粮中添加适当的纤维水平可以通过调节肌纤维类型的表达来改善Er-HL的肉质。