Metabolic adjustments of Dentex dentex to prolonged starvation and refeeding

Abstract

The particular metabolic strategies of the common dentex (Dentex dentex) to face a period of prolonged starvation and subsequent refeeding were assessed. Plasma metabolites, endogenous reserves, and the activity of key enzymes of intermediary metabolism in liver, white muscle, and heart were evaluated. Plasma glucose, total lipid, triglycerides, total-, HDL- and LDL-cholesterol, and protein levels, liver, and white muscle glycogen, and perivisceral, and muscle fat were significantly reduced by starvation, whereas liver lipid content was surprisingly increased. Those enzymes involved in phosphorylation and oxidation of glucose and lipid synthesis, as well as alanine aminotransferase activity, were significantly depressed in liver of starved fish. The increase in β-hydroxyacyl-CoA dehydrogenase (HOAD) indicated an enhanced fatty acid oxidation during starvation. Part of the acetyl-CoA generated by β-oxidation was oxidized in the hepatic Krebs cycle, as reflected the increased citrate synthase (CS) activity. The oxaloacetate required for the reaction catalized by CS activity would be supplied by aspartate aminotransferase (ASAT) activity whose activity was also enhanced. Glutamate dehydrogenase also increased to deaminate the glutamate produced by transaminases, especially by the increased ASAT activity. Liver gluconeogenesis of starved fish was maintained at the same rate that in controls, with glycerol playing an important role as glucogenic substrate. The increased hepatic β-hydroxybutyrate dehydrogenase (β-OHBDH) activity indicates that part of the acetyl-CoA arriving from β-oxidation was being diverted for ketone bodies production with dentex liver playing an important role in providing ketone bodies as fuels for other tissues under such circumstances. Most enzyme activities in white muscle of starved dentex were significantly depressed. In heart, starvation induced an important inhibition of those enzymes involved in glucose and protein metabolism, whereas CS, HOAD, and β-OHBDH activities were maintained at control levels. Although several biomarkers assayed returned to control values after refeeding, many others did not, which indicate that after 3 weeks of refeeding, pre-starved dentex is still experiencing a transient period of metabolic adjustments directed toward the restoration of body mass.

Effect of starvation on some immunological and biochemical parameters in tinfoil barb (Barbonymus schwanenfeldii)

“…Pérez-Jimenez et al (2007) have demonstrated that starvation can decrease in plasma total triglyceride and cholesterol levels during food deprivation periods. Numerous studies have reported a reduction in plasma triglyceride and cholesterol levels during starvation (Hung et al 1997;Polakof et al 2006;Pérez-Jiménez et al 2007;Costas et al 2011;Furné et al 2012;Perez-Jimenez et al 2012). The outcome of the present results and other studies revealed that there will be a decline in glycogen reserves, during the food deprivation period followed by decreased plasma glucose level.…”

“…Similar to the results of present study, Hung et al (1997), Power et al (2000), Furné et al (2012) and Ashouri et al (2013) have reported an increase in plasma protein of several fish species as a result of starvation. In contrast, some studies on teleosts fish have reported the increased levels of plasma protein in response to food deprivation (Heming & Paleczny 1987;Friedrich & Stepanowska 2001;Polakof et al 2006;Costas et al 2011;Perez-Jimenez et al 2012). Unfortunately, no information regarding plasma albumin and globulin due to starvation is available.…”

The Effect of Short-term Starvation on Some Physiological and Morphological Parameters in Juvenile Siberian Sturgeon, Acipenser Baerii (Actinopterygii: Acipenseriformes: Acipenseridae)

“…Similarly, plasma protein decreased in starved mature carp after five days of starvation (Blasco et al 1992). Pérez-Jiménez et al (2012) reported a significant decline in plasma protein levels of common dentex, Dentex dentex (Linnaeus, 1758), after a five-week starvation.…”

Postprandial molecular responses in the liver of the barramundi, Lates calcarifer

“…This enzyme product of this gene functions to link carbohydrate and amino acid metabolism, and increased ALAT activity is connected with enhanced gluconeogenesis and fasting (Méton et al 1999;Fernandez et al 2007;Pérez-Jiménez et al 2012). In fish studied to date, including trout and seabream, one mitochondrial form (mALAT) and two cytosolic isoforms (cALAT1 and cALAT2) have been identified (Méton et al 2004;Fernandez et al 2007;Anaemet et al 2008).…”