Blood Metabolites and Glucose Metabolism in the Fed and Fasted Chicken

Abstract

The effect of fasting on blood metabolites and glucose metabolism in the chicken was studied. Parameters of glucose metabolism were estimated in vivo using a single injection of [2-3H]-glucose or [6-3H]-glucose in combination with [U-14C]-glucose. Plasma glucose, blood lactate and blood acetoacetate levels were not significantly changed in chickens fasted for 72 hours. Pyruvate levels in chickens fasted for 24 hours were higher than those observed in blood from birds fasted 0 to 72 hours. Further, the lactate to pyruvate ratio was lower in chickens fasted for 24 to 72 hours than in fed chickens. Fasting chickens for 24 or 72 hours resulted in three- to fivefold increase in blood beta-hydroxybutyrate levels and a significant increase in beta-hydroxybutyrate to acetoacetate ratio. Plasma levels of alanine and serine were increased after a 24 hour fast but were not further changed when fasting was extended to 72 hours. Plasma aspartate and glutamate levels were not significantly changed in chickens fasted for 24 hours but were markedly decreased in chickens fasted for 72 hours. Plasma levels of glycine were significantly lower in chickens fasted 24 or 72 hours than in fed birds. Glucose replacement rates estimated with [2-3H]-glucose in chickens fasted 0,24 and 72 hours were 14.3, 9.1 and 9.4 mg glucose/minute/kg body weight, respectively. Fasting up to 72 hours did not influence the total body glucose mass in the chickens. The degree of glucose-carbon recycling in 24-hour fasted chickens estimated by using [2-3H]- and [U-14C]-glucose or [6-3H]- and [U-14C]-glucose averaged 42% to 52% and 27% to 30%, respectively. These observations indicate that rate of glucose utilization in the chicken is rapid and that substantial recycling of glucose carbon occurs in fasted chickens.

Lipid metabolism of Tsaiya ducks: plasma and liver related traits underad libitum and fasting

“…After fasting, plasma NEFA increases in ducks, resulting in liver and plasma ketone body concentrations rising. 17,26 Our results are in agreement with this study.…”

“…Belo et al 17 and Tanaka et al 18 indicated that, even during starvation conditions, the blood glucose levels in birds are still high. This fact is attributed to an increase in gluconeogenesis during fasting.…”

“…This may occur because the birds have high levels of blood glucose even during fasting (Tables 2 and 4). 17,18 Blood glucose could be converted intracellularly into glycerol-3-phosphate in adipocytes and increase the re-esteri®cation rate of fatty acids. 22 Therefore, using NEFA concentration as an index of lipolysis in birds may not be an accurate measure.…”

Effect of Fasting on the Levels of Glucose, Free Fatty Acids, Growth Hormone and Somatomedin in the Serum, and on the Pituitary Function of the Chicken

“…Our results on blood glucose levels are similar to those of BELO et al 14), who found no change in plasma glucose and other metabolites in cockerels fasted for 72 hours.…”

Ontogenic Profile of Hexokinase and Glucokinase mRNA Expressions in Embryonic Chicken Liver and Muscle

“…Adult chickens maintain plasma glucose level of around twice higher than adult non-ruminant mammals (Hazelwood and Lorenz, 1959;Belo et al, 1976). Adult chickens could maintain the high level of glucose because they are fed with grain, but it is noteworthy that embryos also maintain high plasma glucose level with a gradual increase during incubation (Langslow, 1978;García et al, 1986), although the embryos depend on the protein-and lipid-rich egg yolk.…”