Effects of fasting and refeeding on metabolic processes in the crabChasmagnathus granulata(Dana, 1851)

Abstract

We assessed the effects of 3 weeks of fasting and 48 h of refeeding on the incorporation of [14C]-labeled substrate into glucose, glycogen, lipid, and protein in hepatopancreas, muscle, and gills from the crab Chasmagnathus granulata. Fasting did not change the rate of glycogen and lipid synthesis in the three tissues. Neither fasting nor refeeding affected hemolymph glucose levels. Refeeding induced a reduction in glycogen synthesis in gills, but did not affect glycogen synthesis in hepatopancreas and muscle. Fasting did not affect lipogenesis in hepatopancreas, but refeeding elevated [14C]-lipid twofold. Muscle lipogenesis was not affected by fasting or refeeding. Gluconeogenesis in the three tissues was not modified by fasting. Refeeding induced an increase in the glucose-synthesis capacity only in muscle. Fasting did not affect glyconeogenesis in hepatopancreas and gills, but induced a reduction in glycogen synthesis in muscle. Muscle-protein synthesis was not affected by fasting; however, refeeding induced a reduction in [14C]-protein. Our data show that C. granulata is a fasting-adapted animal which is able to maintain metabolic homeostasis, and that following refeeding there is an adjustment of anabolic-synthesis processes to recover metabolic reserves that were lost during fasting.

Hepatopancreas gluconeogenesis during anoxia and post‐anoxia recovery in Chasmagnathus granulata crabs maintained on high‐protein or carbohydrate‐rich diets

“…However, the L-lactate levels in the hemolymph declined during post-anoxia recovery and attained the control value at 30h in normoxia. The hepatopancreas may not be the most important organ for lactate reprocessing in this alimentary group, the muscle being a suitable alternative when one considers its gluconeogenic and glyconeogenic potentials, as observed in this animal and in other crabs and fishes (Schein, 2003;Suarez and Mommsen, '87;Vinagre and Da Silva, 2002;Henry et al, '94;Hervant et al, '99a). However, in HC fed crabs during the first 24h of recovery from anoxia, the L-LDH activity was less affected than in HP fed crabs.…”

Starvation effects on physiological parameters and biochemical composition of the hepatopancreas of the southern king crab Lithodes santolla (Molina, 1782)

“…Most species reduce their metabolic rate and deplete protein, glycogen and lipid reserves during nutritional stress (Vinagre & Da Silva 1992, Oliveira et al 2004, Comoglio et al 2005. The relative importance of these reserves and their order of utilization vary according to the species, recent feeding history, diet composition and length of fast (Clifford & Brick 1983, Vinagre & Da Silva 2002, Vinagre et al 2007. Some authors have mentioned that the metabolism in crustaceans is primarily based in glycogen and fatty acids (Welsh 1975, Wen et al 2006, but in contrast decreased levels of protein have been noted during fasting in other marine decapods (Barclay et al 1983, Dall & Smith 1986).…”

Effect of hyperosmotic shock on phosphoenolpyruvate carboxykinase gene expression and gluconeogenic activity in the crab muscle

“…Gluconeogenesis has been demonstrated in the hepatopancreas and gills from C. granulata [12,19]. Among the vertebrates, the enzyme is expressed mainly in liver and kidney, and is located in cytosol and/or mitochondria fraction [16,20].…”