engleski

Effect of fasting on hepatic and renal gluconeogenic enzyme activities in ducklings

Blood glucose concentration, liver and kidney gluconeogenic enzyme activites were investigated during a six-day fasting period in ducklings (English heavy breed Peking Duck). Food deprivation commenced when ducklings reached the age of twenty-eight days. Normally fed ducklings were used as a control group. The ducklings were sacrificed by decapitation after a fasting period of three, four, five and six days, and blood and tissue samples were collected from both groups for analysis. During the experiment the concentration of blood glucose was above 6 mmol/L in both the control and experimental groups, except on experimental day three. Significiant rises in glucose-6-phosphatase (EC 3.1.3.9) (G6Pase) activites in the liver were observed on starvation days four, five and six (P=0.0012, P=0.0109, P=0.0279), and in the kidney on starvation days five and six (P=0.0373, P=0.0206, respectively). Hepatic fructose-1.6-bis-phosphatase (EC 3.1.3.11) (FDPase) activity showed a significant difference between the fasted and control group only after a four-day fast (P=0.0491), whereas renal enzyme activity increased after four (P=0.0279) and six (P=0.0373) days of food deprivation. Phosphoenolpyruvate carboxykinase (EC 4.1.1.32) (PEPCK) activity in the liver of fasted ducklings significantly decreased on fasting day five (P=0.032) was observed in comparison with the normally fed controls. The results showed that ducklings are able to maintain blood glucose concentration during a six-day fasting period. Changes in gluconeogenic enzyme activities indicate the important role of liver and renal gluconeogenesis for the maintenance of blood glucose concentration in fasted ducklings. These findings agree with earlier data obtained on chicken, thus confirming the similarities between the two avian speciec regarding the maintenance of blood glucose level with the process of gluconeogenesis during longer fasting.

carbohydrate metabolism; ducklings; fasting; gluconeogenic enzymes

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