Effect Of AMPK Activity On Energy Metabolism And Meat Quality Of Postmortem Lamb And Its Mechanism Research

Mongolia hybrid sheep were chose to measure the AMPK(AMP-activated protein kinase) activity, glycolysis and meat quality indexs, in order to research the effect of AMPK activity on glycolysis and meat quality, and analyze the possible mechanism of AMPK regulate meat quality. The results showed:1 AMPK reside in the tissues and organs of lamb generally, lung and skeletal muscle have the highest AMPK activity, next are cardiac muscle and small intestine, liver has the lowest AMPK activity. AMPK activity has a very significant difference in the tissues and organs(P<0.01). The AMPK activity of skeletal muscle has a very significant change at 0-24h postmortem(P<0.01), showed a tendency that first increased then decreased, the maximum value emerged at 1h postmortem, then began to decreased, at 24h postmortem it decreased to about 1/2 of 1h postmortem.2 There are greatly difference of AMPK activity and glycolysis indexs in different months, the AMPK activity and glycoclastic speed of 18 months lamb is higher than 6 months lamb. Different parts in the same months has the different AMPK activity and glycolysis indexs, too, all of these may lead to the difference of meat quality in different months and parts.3 The AMPK activity of 6 months lamb has a very significant positive correlation with muscle glycogen content, lactic acid(LD) content, hexokinase(HK) activity, pyruvate kinase(PK) activity and glycolytic potential(GP) (P<0.01), has a very significant negative correlation with pH24 value and L* value (P<0.01), has a significant positive correlation with a* value(P<0.05), has a positive correlation with pHi value and LDH activity, has a negative correlation with shearing force, cooked meat percentage and drip loss, but the differences are not significant; The AMPK activity of 18 months lamb has a very significant positive correlation with HK activity(P<0.01), has a very significant negative correlation with pH24 value(P<0.01), has a significant positive correlation with muscle glycogen content, PK activity, LDH activity and a* value(P<0.05), has a significant negative correlation with drip loss and L* value (P<0.05), has a positive correlation with pHi value, LD and GP, has a negative correlation with shearing force and cooked meat percentage, but the differences are not significant.4 Different storage temperatures have an effect on AMPK activity, glycolysis and meat quality indexs. The higher storage temperature, the higher AMPK activity and glycoclastic speed, the shorter ripening process. On the contrary, The lower storage temperature, the lower AMPK activity and glycoclastic speed, the longer ripening process.5 Accompany with the step up of AMPK activity, glycolytic enzymes activity was enhanced, glycolysis and muscle ripening was accelerated. On the contrary, Accompany with the step down of AMPK activity, glycolytic enzymes activity was degraded, glycolysis and muscle ripening was cut down.Synthesized above-mentioned results, we can conclude that AMPK activity has a significant correlation with glycolysis and meat quality indexs. Exert various conditions on postmortem mutton could change its AMPK activity and glycolysis, to achieve the purpose that improved meat quality. Through AMPK activity regulation, The possible mechanism of AMPK could change meat quality is that, AMPK regulated the glycolysis key enzymes hexokinase, pyruvate kinase and important enzyme lactate dehydrogenase, changed the physical and chemical indexes of glycolysis such as glycogen content, LD accumulation and pH value, so the extent and speed of glycolysis was changed, influenced maturation process of postmortem muscle at the end.