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

Abstract

This study investigated related traits of lipid metabolism in plasma and liver of layer Tsaiya ducks. Each of 60 ducks was randomly allocated into an ad libitum feeding and a three-day fasting group during the growing period (8–12 weeks old) and during the initial laying period (26–30 weeks old; 10–14 weeks from the onset of laying), respectively. Results indicated that, even under ad libitum conditions, Tsaiya ducks had high concentrations of plasma glycerol and ketone bodies. Plasma triacylglycerol (TG) contents of laying ducks were approximately seven-fold higher than those of growing ducks. Contents of liver fat and ketone bodies, plasma phospholipid and non-esterified fatty acid (NEFA) concentrations were higher in the laying period than in the growing period. The lipogenesis-related traits, including blood glucose, plasma TG and phospholipid concentrations, were significantly decreased by fasting (P < 0.05). In contrast, the lipolysis-related traits, including plasma NEFA, glycerol and ketone body concentrations, were significantly increased by fasting (P < 0.05). After fasting, body and liver weights of ducks and contents of abdominal fat and liver TG were significantly decreased (P < 0.05); conversely, concentrations of liver ketone bodies were markedly increased (P < 0.05). This study indicated that fasting depressed lipogenesis and increased lipolysis in Tsaiya ducks. In addition, in laying ducks, lipogenesis was more active than in the growing ducks. © 1999 Society of Chemical Industry