Institute of Feed Science, Zhejiang University, The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, No. 164 Qiutao North Road, Hangzhou 310029, PR China.
J Anim Sci. 2011 Jan;89(1):185-91. doi: 10.2527/jas.2010-2983. Epub 2010 Oct 1.
Western and indigenous Chinese pig breeds show obvious differences in muscle growth and meat quality, however, the underlying molecular mechanism remains unclear. The main objective of this study was to evaluate the breed-specific mechanisms controlling meat quality and postmortem muscle metabolism. The specific purpose was to investigate the variations in meat quality, muscle fiber type, and enzyme activity between local Jinhua and exotic Landrace pigs at the same age (180 d of age), as well as the same BW of 64 kg, respectively. We compared differentially expressed muscle fiber types such as types I and IIa (oxidative), type IIb (glycolytic), as well as type IIx (intermediate) fibers in LM and soleus muscles of Jinhua and Landrace pigs using real-time reverse-transcription PCR. Furthermore, the metabolic enzyme activities of lactate dehydrogenase, as well as succinic dehydrogenase and malate dehydrogenase, were used as markers of glycolytic and oxidative capacities, respectively. Results showed that Jinhua pigs exhibited greater intramuscular fat content and less drip loss compared with the Landrace (P < 0.01). Meanwhile, the mRNA abundance of oxidative and intermediate fibers was increased in Jinhua pigs, whereas the glycolytic fibers were more highly expressed in the Landrace (P < 0.01). In addition, Jinhua pigs possessed greater oxidative capacity than that of the Landrace (P < 0.05). These results suggested that the increased expression of the oxidative and intermediate fibers and greater activities of oxidative enzymes in Jinhua pigs were related to meat quality as indicated by a greater intramuscular fat and reduced drip loss. Based on these results, we conclude that muscle fiber composition and postmortem muscle metabolism can explain, in part, the variation of meat quality in Jinhua and Landrace pigs. These results may provide valuable information for understanding the molecular mechanism responsible for breed specific differences in growth performance and meat quality.
西方和中国本土猪种在肌肉生长和肉质方面表现出明显差异，但潜在的分子机制尚不清楚。本研究的主要目的是评估控制肉质和死后肌肉代谢的品种特异性机制。具体目的是分别研究年龄（180 天）相同和体重（64 公斤）相同的本地金华猪和外来长白猪的肉质、肌肉纤维类型和酶活性的品种特异性差异。我们使用实时逆转录 PCR 比较了金华猪和长白猪的 LM 和比目鱼肌中差异表达的肌肉纤维类型，如 I 型和 IIa 型（氧化型）、IIb 型（糖酵解型）和 IIx 型（中间型）纤维。此外，还将乳酸脱氢酶和琥珀酸脱氢酶以及苹果酸脱氢酶的代谢酶活性分别用作糖酵解和氧化能力的标志物。结果表明，与长白猪相比，金华猪的肌内脂肪含量更高，滴水损失更少（P<0.01）。同时，金华猪的氧化和中间纤维的 mRNA 丰度增加，而长白猪的糖酵解纤维表达更高（P<0.01）。此外，金华猪的氧化能力大于长白猪（P<0.05）。这些结果表明，金华猪的氧化和中间纤维表达增加以及氧化酶活性增强与肉质有关，表现为肌内脂肪增加和滴水损失减少。基于这些结果，我们得出结论，肌肉纤维组成和死后肌肉代谢可以部分解释金华猪和长白猪肉质的变化。这些结果可能为理解生长性能和肉质品种特异性差异的分子机制提供有价值的信息。
