Study on the effect of CaMKKβ‐mediated AMPK activation on the glycolysis and the quality of different altitude postmortem bovineslongissimusmuscle

Abstract

This study investigated the activity of adenosine monophosphate‐activated protein kinase (AMPK), glycolysis, and meat quality index in three altitude bovines during postmortem aging process. Local cattle (altitude:1,500 m), Gannan yak (3,000 m), and Yushu yak (4,500 m) postmortem Longissimus Dorsi (LD) muscle were used. Results indicated that CaCl2 significantly increased the AMPK activity by increasing the calcium‐regulated protein kinase kinase (CaMKKβ) activity. Besides, AMPK activation enhanced the activity of lactate dehydrogenase (LDH) and Ca2+‐ATPase and accelerated the rate of muscle maturation during postmortem aging. Moreover, the expression of HIF‐1, PRKAA2, and GLUT4 genes in high‐altitude Yushu yak was higher than that of low‐altitude bovines. CaCl2 activates AMPK by activating CaMKKβ cascade and accelerates postmortem glycolysis affecting the intramuscular environment, color, and muscle protein degradation to accelerate postmortem muscle maturation, suggesting that AMPK has essential effects on postmortem muscle glycolysis and quality, and can regulate muscle quality by regulating postmortem muscle AMPK activity. Practical applications Insufficient postmortem glycolysis usually leads to DFD (dark, firm, and dry) meat. Beef have relatively high incidences of DFD meat, which has an unattractive dark color and causes significant loss to the meat industry. Therefore, AMPK, which can regulate postmortem glycolysis to affect meat quality, is a valid research target.

H2O2-induced oxidative stress improves meat tenderness by accelerating glycolysis via hypoxia-inducible factor-1α signaling pathway in postmortem bovine muscle

“…3 , it can be demonstrated that ROS is essential for the accumulation of HIF-1α, which further regulates the activation of key glycolytic enzymes (HK and PFK) to enhance glycolytic potential early postmortem. Our results are partly consistent with those of Gao et al (2019) , who indicated that the greater glycolytic enzyme activity and glycolysis rate of yak meat within 24 h postmortem are attributed to its higher expression level of HIF-1α.

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Study on the HIF ‐1α regulated by glycolytic pathways and mitochondrial function in yaks of different altitudes during postmortem aging

“…These results not only showed that YC‐1 could inhibit the decrease in pH but also indicated that HIF‐1α was related to the decrease in pH during postmortem aging. The observations were consistent with those of Gao et al (2019) who pointed out that the pH value was inversely proportional to the altitude where the yaks grow and that it reached its lowest value at 72 hr. HIF‐1α guides the glycolysis pathway by promoting the expression of glucose transporters and glycolytic enzymes and by decreasing the pH value (Gordan et al, 2007), with the mitochondria also increasing the rate of pH and ATP decline (Hudson et al, 2012).…”

“…These results were consistent with those reported by Soñanez-Organis et al (2012), where the silencing of HIF-1α inhibited the increase of LDH activity produced by a cell under hypoxic conditions. In addition, Gao et al (2019) found that LDH and HK activities not only showed an upward trend prior to a downward one as the postmortem period of yak muscles increased but also that the activities were highest in high-altitude yaks. Shen et al (2014) also observed that high levels of mRNA for genes related to HK contributed to high glycogen content, glycolytic rate, and glycolytic potential (GP) in "fast-glycolytic-type" muscles.…”

“…As a result, a glycolytic pathway is activated to increase glycogen consumption to meet the cellular demands in energy (Nagao et al, 2019). It has been reported that the longissimus dorsi muscle of yak is more prone to glycolysis than beef cattle (Gao et al, 2019). Furthermore, there are significant differences in the energy metabolism of animals raised at three different altitudes, with the glycolytic potential being proportional to the altitude (Shen et al, 2014).…”

“…So far, HIF-1α was studied for medical, biomedical, and biochemical purposes, but recently, it attracted the attention of meat specialists due to its regulatory role in postmortem meat quality and aging (Fan et al, 2020). Gao et al (2019) found that HIF-1α expression in yak and beef was significantly different at different altitudes, and that the higher the altitude, the more severe the hypoxia, and the higher the expression of HIF-1α. However, the influence of HIF-1α on the activity of glycolytic enzymes as well as mitochondrial function remains unknown, especially during the important process of postmortem aging.…”