The ability of fed or fasted 30-day-old pigs to utilize intravenously administered glucose-oligosaccharides (supplied at 20 g/day) was compared in a randomized crossover design. Six pigs were fed a stock diet from days 10 to 30 of life. A central venous catheter was placed on day 30. From days 30 to 39 of life, either a balanced electrolyte solution or a glucose-oligosaccharide solution was infused through the intravenous (i.v.) catheter. On the first i.v. feeding day, all animals were infused with an isotonic, balanced electrolyte solution and were allowed food and water ad libitum per os. On days 2 through 5 of the i.v. period, 3 animals received glucose-oligosaccharides intravenously (20 g/day), with all other needed nutrients, including energy, supplied enterally. On days 6-9 of the i.v. infusion period these animals continued to receive oligosaccharides intravenously, but were denied food. The other three animals were infused with oligosaccharides in the fed or fasting state in the reverse order. Based on urinary carbohydrate excretion, mean (+/- SD) glucose-oligosaccharide utilization was 92% whether the animals were fed or fasted. These results differ from those observed in fasted human subjects.