Effects of anoxia and post-anoxia recovery on carbohydrate metabolism in the jaw muscle of the crab Chasmagnathus granulatus maintained on carbohydrate-rich or high-protein diets

The present study assesses the effects of 1-h anoxia and 3-h post-anoxia recovery period on the activity of pyruvate kinase (PK), 14CO2 produced from 14C-glucose and 14C-lactate, ATP, and glycogen levels in the jaw muscle of Chasmagnathus granulatus fed either a carbohydrate-rich (HC) or high-protein (HP) diet.In the HC control group the jaw muscle PK activity was higher than in HP-fed crabs. In jaw muscle from control HP-fed crabs the lactate oxidation was higher than in HC-fed animals. We observed increased PK activity and ATP concentration and a reduction in the glycogen concentration, 14CO2 production from 14C-lactate in HP-fed crab jaw muscle during anoxia. In crabs fed an HC diet the PK activity decreased in anoxia, the 14CO2 production from 14C-glucose increased, and the 14CO2 production from 14C-lactate did not change.During recovery, a low oxidation capacity for lactate was found in jaw muscle of both dietary groups. PK activity and 14CO2 production from 14C-glucose were high during the recovery period only in the jaw muscle from HP-fed crabs.Recovery decreased the ATP concentration of both dietary groups as compared to anoxia and normoxia, and did not restore the glycogen concentration in the jaw muscle.