Effect of feeding on intravenous glucose tolerance and insulin response in piglets during the first day of life

Abstract

The influence of postnatal age and nutritional status on the disappearance rate of glucose (k G value), the insulin response and the changes in plasma free fatty acids and glycerol following an intravenous glucose load have been studied in 37 piglets during the first 24 hours of life. Groups of fed and starved animals were studied at 1−1 1 2 , 7–12 and 16–24 hours of age. A group fed 4 hours and subsequently starved for 20 hours was also studied. In fed piglets there was a rise in k G value accompanied by a marked increase in insulin response during the first day of age. In starved animals there was no change in k G value with age and only the oldest age group showed an increase in insulin response, less than that seen in fed animals. The fed-starved group had k G values similar to fed animals and insulin responses intermediate between those of fed and starved animals of comparable ages. The plasma free fatty acid and glycerol concentrations were low in all groups of piglets and showed only minimal changes following the glucose load. The results indicate that in the piglet the increase in k G value during the first day of life is dependent on food intake rather than on age. Although the insulin response following an intravenous glucose load improves with age, it is markedly augmented by feeding.