Forty-four pure Iberian pigs were reared under four different rearing systems: i. Free range conditions and fed on acorns and pasture (AGFR), ii. Free range conditions with grass availability and fed on concentrate (CGFR), iii. Intensive system and fed on concentrate supplemented with 100 ppm of α-tocopheryl acetate (α-Tac) (CI) and iv. Intensive system and fed on concentrate supplemented with 200 ppm α-Tac (CEI). The aim was to investigate the effect of rearing system on pH values, glycogen content [GLY] and lactate content [LAC], myofibrillar and sarcoplasmic proteins solubility and metabolic rate (R-value) in muscle Longissimus dorsi (L. dorsi) at 45 min and 24 h postmortem. In addition, at 24 h postmortem, water holding capacity (WHC), cook loss (CL), drip loss (DL) and instrumental color were analysed. mRNA expression of genes related to glycogenolysis (glycogen phosphorylase, muscle associated: PYGM) and glucose metabolism, both aerobic (pyruvate dehydrogenase kinase 4: PDK4) and anaerobic pathways (lactate dehydrogenase A: LDHA) were sampled within 45 min postmortem. AGFR muscles at 45 min postmortem had a significantly higher [GLY] than CI (P < 0.05). CEI and CGFR muscle [GLY] did not differ from CI and AGFR, with intermediate values. [LAC], pH, R-value and protein solubility, both at 45 min and 24 h postmortem, did not differ among groups. Rearing system did not affect meat quality parameters, with the exception of redness (CIE a*) that was significantly higher in muscle from AGFR pigs than in those from CEI and CGFR pigs. Meanwhile, PYGM mRNA showed overexpression in AGFR, CGFR and CEI groups compared to CI. No significant differences were found for LDHA and PDK4 genes between batches. Regarding correlations, pH had significant positive correlations with WHC and negative with CL and lightness (CIEL L*). [LAC] correlated positively with CL and CIE L * and negatively with WHC; while the pH did the opposite. The expression of the LDHA gene was negatively correlated with pH and positively with [LAC]. Positive correlations were found between PDK4 gene expression and pH and negative correlations with [LAC].

在四种不同的饲养系统下饲养了四十四只伊比利亚纯种猪：自由放养条件，以橡子和牧场（AGFR）为食，ii。放牧条件良好且有草并饲喂精矿（CGFR）iii。强化系统，饲喂补充有100 ppm的α-生育酚乙酸酯（α-Tac）（CI）的浓缩液和iv。集约化系统并饲喂补充有200 ppmα-Tac（CEI）的精矿。目的是研究饲养系统对45岁的背最长肌（背最长肌）的pH值，糖原含量[GLY]和乳酸含量[LAC]，肌原纤维和肌浆蛋白溶解度和代谢率（R值）的影响。死后24小时内。此外，在死后24小时，保水量（WHC），蒸煮损失（CL），滴漏损失（DL）和仪器颜色进行了分析。在死后45分钟内取样与糖原分解相关的基因（糖原磷酸化酶，肌肉相关：PYGM）和葡萄糖代谢，有氧（丙酮酸脱氢酶激酶4：PDK4）和厌氧途径（乳酸脱氢酶A：LDHA）的mRNA表达。死后45分钟的AGFR肌肉的[GLY]明显高于CI（P <0.05）。CEI和CGFR肌肉[GLY]与CI和AGFR没有区别，中间值。死后45分钟和24小时的[LAC]，pH，R值和蛋白质溶解度，组之间没有差异。饲养系统不影响肉的质量参数，除了发红（CIE a *）明显例外，AGFR猪的肌肉发红比CEI和CGFR猪的发红高。同时，与CI相比，PYGM mRNA在AGFR，CGFR和CEI组中显示过表达。批次之间的LDHA和PDK4基因没有发现显着差异。关于相关性，pH与WHC呈显着正相关，与CL和亮度（CIEL L *）呈负相关。[LAC]与CL和CIE L *正相关，与WHC负相关；而pH值则相反。LDHA基因的表达与pH呈负相关，与[LAC]呈正相关。发现PDK4基因表达与pH呈正相关，与[LAC]呈负相关。