Body composition, energy expenditure, and plasma metabolites in long-term fasting geese

Abstract

Starvation in 15 geese (mean initial body mass, m = 6.3 kg) fasting for about 40 days (mean decrease in m = 2.5 kg) was characterized by three periods. Period I (3-8 days), an adaptation period, was marked by a considerable decrease in the daily rate of change in m (dm) as well as in resting metabolic rate (RMR), and by high fat mobilization. In period II (a period of economy) the decreases in dm, RMR, and daily rate of nitrogen excretion (dne) were reduced: when expressed per unit of body mass these rates were either constant or decreased slightly. Period III, a critical period, was characterized by a rapid increase in both dm and dne that appeared when body mass had dropped to 4.7-3.2 kg. In parallel there was a greater decrease in intracellular fluid volume below 5 kg. Throughout the fast, in contrast to fasting mammals, plasma glucose and alanine concentrations were maintained at high levels (8-10 and 0.4 mM, respectively), and there was no increase in acetoacetate. However, after 20 days of fasting, plasma beta-hydroxybutyrate concentration (beta-OHB) increased to about 20 mM, while blood pH remained constant and blood PCO2 decreased. Thus, compensation for metabolic acidosis was partly attributed to respiratory alkalosis. Throughout the fast, the variations in beta-OHB were a mirror image of those for daily changes in body mass and in nitrogen excretion. This presumably reflects a hormonal change, but might also suggest a key role of beta-OHB in the control of energy expenditure and/or in regulation of body mass as well as in protein sparing.

Different variations of tissue B-group vitamin concentrations in short- and long-term starved rats

“…Accordingly, decreased acetylation and biotin-dependent enzymes lead to reduced fatty acid oxidation and to save fat in the body. Vitamin B 6 concentrations, expected to be the last vitamin decreased in tissues by starvation (3) , decreased in the stomach, skeletal muscle and serum of the S2 rats. Vitamin B 6 in the lung and serum decreased in the S6 rats.…”

“…2(F)). Whole blood vitamin B 1 , serum vitamin B 6 and plasma pantothenic acid concentrations decreased in the S6 and P3 rats. Plasma folate and biotin concentrations decreased in the P3 rats.…”

“…Vitamin B 1 catalyses carbohydrate metabolism including decarboxylation of a-ketoacids and trans-ketolation as a cofactor thiamin diphosphate; vitamin B 6 functions as pyridoxal 5 0 -phosphate in amino acid metabolism including aminotransferases, decarboxylases, racemases and dehydratases as pyridoxal 5 0 -phosphate; and pantothenic acid is involved in fatty acid metabolism such as oxidation and synthesis. For these reasons, in the 'Dietary Reference Intakes for Japanese, 2010', dietary requirements for vitamin B 1 , vitamin B 2 and niacin are expressed per 4186 kJ (1000 kcal), and the requirement for vitamin B 6 is expressed in terms of protein intake (12) .…”

Factors Affecting Plasma Concentrations of Prolactin in the Common Eider Somateria mollissima

“…Blood samples were taken at capture and then once every 5 days. The experimentation was stopped when fasting females entered into the first day of phase III (see Le Maho et al, 1981), and then the last blood sample was taken. After the experiment, the birds were refed and released.…”

“…Female eiders facing an artificially extended incubation start to feed again (Criscuolo et al, 2001). To test whether the nutritional status of the bird can influence its prolactin concentration, we determine the plasma concentrations of triacylglycerols (feeding indice) and of β-hydroxybutyrate (fasting indice, Le Maho et al, 1981) of prolonged incubating females.…”