Net Fluxes of Amino Acids Across the Portal-Drained Viscera and the Liver of Pigs Fed a Diet Adequate or Deficient in Lysinea

The effect of varying dietary lysine supply from low to adequate levels on amino acid partitioning across splanchnic tissues was investigated in growing barrows prepared with permanent indwelling catheters placed in the carotid artery, portal vein and hepatic vein. Pigs (32.9 (SD) 1.4 kg) were fed either a lysine-deficient diet (L1; n=9) or a lysine-adequate diet (L2; n=7) according to a completely randomised design. On day 16, ρAH (2%) was infused for 9 h into the ileal vein. Blood samples were collected from all vessels at 1, 2, 3, 4, 5, 6, 7, 8, 9 h after the beginning of infusion to measure concentration of ρAH and amino acids. The plasma flow across portal-drained viscera and splanchnic tissues was similar (p>0.05) between diets. Plasma lysine concentration increased (p<0.05) with lysine supplementation whilst that of most other amino acids decreased (p<0.05). Lysine appearance in the portal vein was increased (p<0.05) with lysine supplementation with 60% of additional lysine taken up by the liver. Supplementation seemed to affect the net fluxes of non essential amino acids such as alanine and glutamate probably because of reduced amino acid oxidation. These amino acids are involved in transamination and inter-organ nitrogen transport.