不同海拔高度牛宰后牛肉AMPK活性及能量代谢研究

为了研究不同海拔高度生长的牛宰后牛肉一磷酸腺苷活化蛋白激酶(AMPK)活性与糖酵解指标,以探讨宰后肌肉生理机理,测定了玉树牦牛(海拔4 500 m)、甘南牦牛(海拔3 000 m)和西门塔尔杂交肉牛(海拔1 500 m)宰后成熟过程中牛肉AMPK活性、AMPK基因(PRKAA1、PRKAA2)mRNA表达量、糖酵解和能量代谢的变化。结果表明,12~168 h时间内,AMPK活性从小到大依次为西门塔尔杂交牛、甘南牦牛、玉树牦牛;西门塔尔杂交牛PRKAA1基因的表达量比甘南牦牛和玉树牦牛略低;西门塔尔杂交牛PRKAA2基因表达量显著小于甘南牦牛和玉树牦牛(P0.05);72~168 h时间内,乳酸含量和游离葡萄糖含量从小到大依次为西门塔尔杂交牛、甘南牦牛、玉树牦牛,p H值、肌糖原含量从大到小依次为西门塔尔杂交牛、甘南牦牛、玉树牦牛;成熟前期ATP、ADP、AMP含量从大到小依次为西门塔尔杂交牛、甘南牦牛、玉树牦牛。高海拔品种牛肉机体PRKAA1和PRKAA2基因表达量高时,AMPK被激活从而活性增加,ATP的浓度水平降低,AMP生成量增加,加速组织内的糖酵解,增加肌肉乳酸含量,降低p H值,进而影响牛肉品质。

AMPK Activity and Glycolysis of Postmortem Beef at Different Altitudes

With the aim to explore the effects of AMPK activity, AMPK mRNA expression (PRKAA1, PRKAA2) in beef during the post-mortem period were measured in Yushu yak (4500m above sea level), Gannan yak (3000m above sea level) and Simmental hybrid beef (1500m above sea level) changes in glycolysis and energy metabolism. The results showed that the AMPK activities was in a ascending trend as Simmental hybrids, Gannan yak and Yushu yak;the expression of PRKAA1 in Simmental hybrid was slightly lower than that in Gannan and Yushu;the expression of PRKAA2 in Simmental hybrid was significantly lower than that in Gannan and Yushu (P<0.05). In 12~168h, lactate content and free glucose content were in a ascending trend as Simmental hybrid cattle, Gannan yak and Yushu yak;in 72~168h, pH value and muscle glycogen content were in a descending trend as Simmental hybrid cattle, Gannan yak and Yushu yak;early maturity ATP, ADP and AMP were in a descending trend as Simmental hybrid cattle, Gannan yak and Yushu yak. In summary, as PRKAA1 and PRKAA2 gene expression in high-altitude beef body was high, AMPK was activated to increase activity, ATP concentration was lower, AMP production was increased, tissue glycolysis was accelerated, muscle lactate content was increase and pH value was lowered, thus affecting the quality of meat. The activity of AMPK in beef was increased under high altitude with hypoxia adaptability, which accelerated glycolysis metabolism and more effectively regulated energy generation.