The splanchnic bed is a group of organs (liver, intestines, stomach, pancreas and spleen) which are active in the metabolism of amino acids. However, the impact of this group of organs on the dietary requirements of humans has yet to be determined. The focus of this research will be the requirements of two indispensable amino acids, threonine and lysine, and the impact of the splanchnic bed on amino acid kinetics. Threonine is an indispensable amino acid which is critical in the production of mucins in the gut and contributes significantly to collagen, elastin and tooth enamel formation in mammals. The first study was designed to determine the threonine requirement for the parenterally-fed, stable, post-surgical neonate. The mean threonine parenteral requirement, as experimentally derived in human neonates, was 32.8 mg•kg-1•d-1 which was less than the recommended enteral intake of 76 mg•kg-1•d-1 suggesting a splanchnic uptake in humans of 57%. Lysine is an indispensable amino acid used primarily, in the mammalian body, for protein synthesis but it also acts as a precursor for carnitine synthesis. The second study was devised to determine the lysine requirement for the parenterally-fed, stable, post-surgical neonate. The mean lysine parenteral neonatal requirement as experimentally determined in human neonates, was 104.9 mg•kg-1•d-1 which was less than the recommended enteral intake of 119 mg•kg-1•d-1 suggesting a splanchnic uptake in humans of 12%. The third study was intended to increase our knowledge of the metabolism of threonine and lysine by the splanchnic bed. Adult humans were fed isotopic threonine and lysine both enterally and parenterally. We determined that retention of threonine and lysine by the splanchnic bed was 16.7% and 17.1% respectively, which were not significantly different. The conclusion was that, in healthy human adult males, there was no difference in the extraction of threonine and lysine by the splanchnic bed which was different from our findings in parenterally fed piglets and human neonates.

The splanchnic bed is a group of organs (liver, intestines, stomach, pancreas and spleen) which are active in the metabolism of amino acids. However, the impact of this group of organs on the dietary requirements of humans has yet to be determined. The focus of this research will be the requirements of two indispensable amino acids, threonine and lysine, and the impact of the splanchnic bed on amino acid kinetics. Threonine is an indispensable amino acid which is critical in the production of mucins in the gut and contributes significantly to collagen, elastin and tooth enamel formation in mammals. The first study was designed to determine the threonine requirement for the parenterally-fed, stable, post-surgical neonate. The mean threonine parenteral requirement, as experimentally derived in human neonates, was 32.8 mg•kg-1•d-1 which was less than the recommended enteral intake of 76 mg•kg-1•d-1 suggesting a splanchnic uptake in humans of 57%. Lysine is an indispensable amino acid used primarily, in the mammalian body, for protein synthesis but it also acts as a precursor for carnitine synthesis. The second study was devised to determine the lysine requirement for the parenterally-fed, stable, post-surgical neonate. The mean lysine parenteral neonatal requirement as experimentally determined in human neonates, was 104.9 mg•kg-1•d-1 which was less than the recommended enteral intake of 119 mg•kg-1•d-1 suggesting a splanchnic uptake in humans of 12%. The third study was intended to increase our knowledge of the metabolism of threonine and lysine by the splanchnic bed. Adult humans were fed isotopic threonine and lysine both enterally and parenterally. We determined that retention of threonine and lysine by the splanchnic bed was 16.7% and 17.1% respectively, which were not significantly different. The conclusion was that, in healthy human adult males, there was no difference in the extraction of threonine and lysine by the splanchnic bed which was different from our findings in parenterally fed piglets and human neonates.