Climate change and the associated risk for the occurrence of extreme temperature events or permanent changes in ambient temperature are important in the husbandry of farm animals. The aim of our study was to investigate the effects of permanent cultivation temperatures below (35 °C) and above (39 °C, 41 °C) the standard cultivation temperature (37 °C) on porcine muscle development. Therefore, we used our porcine primary muscle cell culture derived from satellite cells as an in vitro model. Neonatal piglets have limited thermoregulatory stability, and several days after birth are required to maintain their body temperature. To consider this developmental step, we used myoblasts originating from thermolabile (five days of age) and thermostable piglets (twenty days of age). The efficiency of myoblast proliferation using real-time monitoring via electrical impedance was comparable at all temperatures with no difference in the cell index, slope or doubling time. Both temperatures of 37 °C and 39 °C led to similar biochemical growth properties and cell viability. Only differences in the mRNA expression of myogenesis-associated genes were found at 39 °C compared to 37 °C with less MYF5, MYOD and MSTN and more MYH3 mRNA. Myoblasts grown at 35 °C are smaller, exhibit higher DNA synthesis and express higher amounts of the satellite cell marker PAX7, muscle growth inhibitor MSTN and metabolic coactivator PPARGC1A. Only permanent cultivation at 41 °C resulted in higher HSP expression at the mRNA and protein levels. Interactions between the temperature and donor age showed that MYOD, MYOG, MYH3 and SMPX mRNAs were temperature-dependently expressed in myoblasts of thermolabile but not thermostable piglets. We conclude that 37 °C to 39 °C is the best physiological temperature range for adequate porcine myoblast development. Corresponding to the body temperatures of piglets, it is therefore possible to culture primary muscle cells at 39 °C. Only the highest temperature of 41 °C acts as a thermal stressor for myoblasts with increased HSP expression, but it also accelerates myogenic development. Cultivation at 35 °C, however, leads to less differentiated myoblasts with distinct thermogenetic activity. The adaptive behavior of derived primary muscle cells to different cultivation temperatures seems to be determined by the thermoregulatory stability of the donor piglets.

中文翻译：

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温度对不同体温调节成熟期供体仔猪成肌细胞增殖的影响

气候变化以及发生极端温度事件或环境温度永久性变化的相关风险在农场动物饲养中很重要。我们研究的目的是调查低于 (35 °C) 和高于 (39 °C, 41 °C) 标准培养温度 (37 °C) 的永久培养温度对猪肌肉发育的影响。因此，我们使用源自卫星细胞的猪原代肌肉细胞培养物作为体外模型。新生仔猪的体温调节稳定性有限，需要在出生后几天保持体温。为了考虑这一发育步骤，我们使用了来自不耐热（五日龄）和耐热仔猪（二十日龄）的成肌细胞。使用电阻抗实时监测的成肌细胞增殖效率在所有温度下都具有可比性，细胞指数、斜率或倍增时间没有差异。37 °C 和 39 °C 的温度都导致类似的生化生长特性和细胞活力。与 37°C 相比，仅在 39°C 下发现肌生成相关基因的 mRNA 表达存在差异，其中 MYF5、MYOD 和 MSTN 较少，而 MYH3 mRNA 较多。在 35 °C 下生长的成肌细胞更小，表现出更高的 DNA 合成，并表达更高量的卫星细胞标记 PAX7、肌肉生长抑制剂 MSTN 和代谢辅激活剂 PPARGC1A。只有在 41°C 下永久培养才能在 mRNA 和蛋白质水平上产生更高的 HSP 表达。温度和供体年龄之间的相互作用表明 MYOD、MYOG、MYH3 和 SMPX mRNA 在不耐热但不耐热的仔猪的成肌细胞中呈温度依赖性表达。我们得出结论，37 °C 至 39 °C 是猪成肌细胞充分发育的最佳生理温度范围。与仔猪的体温相对应，因此可以在 39 °C 下培养初级肌肉细胞。只有 41 °C 的最高温度才能作为 HSP 表达增加的成肌细胞的热应激源，但它也会加速肌源性发育。然而，在 35 °C 下培养会导致分化程度较低的成肌细胞具有明显的产热活性。衍生的原代肌肉细胞对不同培养温度的适应性行为似乎取决于供体仔猪的体温调节稳定性。