Moeller S J, Baas T J, Leeds T D, Emnett R S, Irvin K M
The Ohio State University, Columbus 43210, USA.
J Anim Sci. 2003 Feb;81(2):402-10. doi: 10.2527/2003.812402x.
The purpose of the present study was to compare Rendement Napole (RN) classification from glycolytic potential (GP) and DNA techniques, and to study the effect of the RN gene on performance, carcass, muscle quality, and sensory traits. Progeny (N = 118) from the mating of 15 purebred Hampshire sires to York x Landrace females were classified for RN gene status using the GP of the loin and polymerase chain reaction-restriction fragment length polymorphism sequence methodology. Females mated in the study (N = 32) were considered normal (rn+/rn+) based on a loin GP measurement taken on samples collected by live press biopsy. Progeny were randomly selected for harvest within a litter for each sire. Observed mean, standard deviation, and range of progeny loin GP values were 132.2, 30.7, and 70.0 to 193.0 micromol/g, respectively. The GP data were not normally distributed. Peak numbers of observations occurred between 120 and 129 micromol/g and 160 to 169 micromol/g. Pigs with a loin GP of > 150 micromol/g were classified RN-/rn+ based on the observed valley between the peak values, resulting in 37 pigs classified as RN-/rn+ and 81 pigs classified as rn+/rn+. Using DNA procedures, 81 RN-/rn+ and 37 rn+/rn+ pigs were observed. All classification errors occurred when GP values were < or = 150 micromol/g, with 30 of 44 and 14 of 44 classification errors occurring when loin GP values were between 121 and 150 micromol/g and 70 and 120 micromol/g, respectively. Gene effects, based on DNA results, were evaluated using mixed-model procedures with fixed effects of DNA genotype and gender, and random sire and litter effects. No RN genotype differences for growth rate,10th-rib backfat, or loin muscle area were observed. Loins from the RN-/rn+ pigs had significantly (P < 0.05) lower ultimate pH (0.16 units), greater GP (50.3 micromol/g), greater drip loss (0.93%), paler objective color (L*, 1.66 units), paler visual color (0.31 units), and lower firmness (0.61 units) scores. Additionally, loins from RN-/rn+ pigs had significantly (P < 0.05) lower marbling scores (0.68 units) and intramuscular fat content (0.25%) and greater cooking loss (2.51%). Cooked moisture, juiciness score, and mechanical and sensory tenderness measures did not differ between genotypes. The GP-based classification did not correctly classify RN genotype in the present study, emphasizing the importance of the direct DNA analysis for estimation of gene frequency and effects. The DNA-based genotype results clearly indicate the RN- allele has negative effects on muscle quality measures.
本研究的目的是比较基于糖酵解潜力（GP）和DNA技术的拿破仑效率（RN）分类，并研究RN基因对生产性能、胴体、肌肉品质和感官特性的影响。使用腰部的GP和聚合酶链反应-限制性片段长度多态性序列方法，对15头纯种汉普夏种公猪与约克夏×长白母猪交配产生的后代（N = 118）进行RN基因状态分类。根据通过活体按压活检采集的样本测量的腰部GP，本研究中交配的母猪（N = 32）被认为是正常的（rn+/rn+）。在每个父系的一窝仔猪中随机选择后代进行屠宰。观察到的后代腰部GP值的平均、标准差和范围分别为132.2、30.7以及70.0至193.0微摩尔/克。GP数据不呈正态分布。观察值的峰值出现在120至129微摩尔/克和160至169微摩尔/克之间。根据观察到的峰值之间的谷值，腰部GP>150微摩尔/克的猪被分类为RN-/rn+，结果37头猪被分类为RN-/rn+，81头猪被分类为rn+/rn+。使用DNA程序，观察到81头RN-/rn+猪和37头rn+/rn+猪。所有分类错误都发生在GP值≤150微摩尔/克时，当腰部GP值分别在121至150微摩尔/克和70至120微摩尔/克之间时，44个分类错误中有30个和14个发生。基于DNA结果，使用混合模型程序评估基因效应，固定效应为DNA基因型和性别，随机效应为父系和窝效应。未观察到RN基因型在生长速度、第10肋背膘厚或腰部肌肉面积方面的差异。RN-/rn+猪的腰部最终pH值显著更低（P < 0.05，低0.16个单位），GP更高（高50.3微摩尔/克），滴水损失更大（0.93%），客观颜色更浅（L*，浅1.66个单位），视觉颜色更浅（浅0.31个单位），硬度得分更低（低0.61个单位）。此外，RN-/rn+猪的腰部大理石花纹得分显著更低（P < 0.05，低0.68个单位），肌内脂肪含量更低（低0.25%），烹饪损失更大（2.51%）。不同基因型之间的熟肉水分、多汁性得分以及机械和感官嫩度指标没有差异。在本研究中，基于GP的分类未能正确分类RN基因型，强调了直接DNA分析在估计基因频率和效应方面的重要性。基于DNA的基因型结果清楚地表明RN-等位基因对肌肉品质指标有负面影响。
