Effect of fasting and refeeding on gluconeogenesis and glyconeogenesis in the muscle of the crab Chasmagnathus granulatus previously fed a protein- or carbohydrate-rich diet

The present study investigated the participation of the muscle gluconeogenic and glyconeogenic pathways in lactate metabolism after 15 fasting and during different periods of refeeding in Chasmagnathus granulatus previously maintained on a carbohydrate-rich (HC) or high-protein (HP) diet. In C. granulatus the metabolic adjustments during the fasting use different pathways according to the composition of the diet previously offered to the crab. During fasting, the gluconeogenic capacity is reduced in crabs maintained on the HC diet. In animals maintained on the HP diet, an increase in activity of the glyconeogenic pathway occurs after 15 days of fasting. In the animals fed HC diet, the glyconeogenesis is one of the pathways responsible for maintenance of the lactate levels in the fed and refeeding states. In crabs fed on the HP diet, the gluconeogenesis and glyconeogenesis pathways are involved in the reduction of lactate levels during the refeeding period. This study shows that protein or carbohydrates levels in the diet previously administrated to the crabs modulate the gluconeogenesis, glyconeogenesis in muscle and lactate concentration in the hemolymph in fed, fasting and refeeding states.