中等海拔地区育肥安格斯牛肺动脉压对宰后早期线粒体功能和零售展示期间肉色的影响。
Pulmonary arterial pressure in fattened Angus steers at moderate altitude influences early postmortem mitochondria functionality and meat color during retail display.
机构信息
Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523, USA.
Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
出版信息
J Anim Sci. 2022 Feb 1;100(2). doi: 10.1093/jas/skac002.
Pulmonary hypertension is a noninfectious disease of cattle at altitudes > 1524 m (5,000 ft). Mean pulmonary arterial pressures (PAP) are used as an indicator for pulmonary hypertension in cattle. High PAP cattle (≥50 mmHg) entering the feedlot at moderate elevations have lower feed efficiency as compared to low PAP cattle (< 50 mmHg). The impact of pulmonary arterial pressure on mitochondrial function, oxidative phosphorylation (OXPHOS) protein abundance, and meat color was examined using longissimus lumborum (LL) from high (98 ± 13 mmHg; n = 5) and low (41 ± 3 mmHg; n = 6) PAP fattened Angus steers (live weight of 588 ± 38 kg) during early postmortem period (2 and 48 h) and retail display (days 1 to 9), respectively. High PAP muscle had greater (P = 0.013) OXPHOS-linked respiration and proton leak-associated respiration than low PAP muscles at 2 h postmortem but rapidly declined to be similar (P = 0.145) to low PAP muscle by 48 h postmortem. OXPHOS protein expression was higher (P = 0.045) in low PAP than high PAP muscle. During retail display, redness, chroma, hue, ratio of reflectance at 630 and 580 nm, and metmyoglobin reducing activity decreased faster (P < 0.05) in high PAP steaks than low PAP. Lipid oxidation significantly increased (P < 0.05) in high PAP steaks but not (P > 0.05) in low PAP. The results indicated that high PAP caused a lower OXPHOS efficiency and greater fuel oxidation rates under conditions of low ATP demand in premortem beef LL muscle; this could explain the lower feed efficiency in high PAP feedlot cattle compared to low PAP counterparts. Mitochondrial integral function (membrane integrity or/and protein function) declined faster in high PAP than low PAP muscle at early postmortem. LL steaks from high PAP animals had lower color stability than those from the low PAP animals during simulated retail display, which could be partially attributed to the loss of muscle mitochondrial function at early postmortem by ROS damage in high PAP muscle.
肺动脉高压是海拔>1524 米（5000 英尺）的牛的一种非传染性疾病。平均肺动脉压（PAP）被用作牛肺动脉高压的指标。在中等海拔进入饲养场的高 PAP 牛（≥50mmHg）的饲料效率低于低 PAP 牛（<50mmHg）。使用来自高 PAP（98±13mmHg；n=5）和低 PAP（41±3mmHg；n=6）育肥安格斯牛的背最长肌（活重 588±38kg），在宰后早期（2 和 48 小时）和零售展示（1 至 9 天）期间，检查肺动脉压对线粒体功能、氧化磷酸化（OXPHOS）蛋白丰度和肉色的影响。高 PAP 肌肉的 OXPHOS 相关呼吸和质子泄漏相关呼吸大于低 PAP 肌肉（P=0.013），但在 48 小时后迅速下降到与低 PAP 肌肉相似（P=0.145）。OXPHOS 蛋白表达在低 PAP 中高于高 PAP 肌肉（P=0.045）。在零售展示期间，高 PAP 牛排的红色、色饱和度、色调、630 和 580nm 反射率比值和高铁血红蛋白还原活性下降速度快（P<0.05），低 PAP 牛排则下降速度慢。高 PAP 牛排的脂质氧化显著增加（P<0.05），而低 PAP 牛排则没有（P>0.05）。结果表明，在宰前牛肉背最长肌低 ATP 需求条件下，高 PAP 导致 OXPHOS 效率降低和燃料氧化速率增加；这可以解释高 PAP 饲养场牛的饲料效率低于低 PAP 牛的原因。在宰后早期，高 PAP 比低 PAP 肌肉的线粒体整体功能（膜完整性和/或蛋白功能）下降速度更快。在模拟零售展示期间，高 PAP 动物的背最长肌牛排的颜色稳定性低于低 PAP 动物，这可能部分归因于高 PAP 肌肉中 ROS 损伤导致宰后早期肌肉线粒体功能丧失。
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