Fig. 2.
Infusion schedule. Piglets were feed deprived for 8 h before the beginning of the infusion. The infusion schedule consisted of a fasted and fed period. During the fasted period (0–3 h), [U-13Cn]arginine, -glutamine, or -proline were infused iv. During the fed period, the U-13Cn tracers were infused iv (3–7 h) and ig (7–11 h). In addition, citrulline, ornithine, phenylalanine, and tyrosine tracers were infused iv for the entire infusion. Blood samples were collected for isotopic enrichment determination at the beginning of the infusion and at 2, 2.5, 3, 6, 6.5, 7, 10, 10.5, and 11 h.