The indicator amino acid oxidation method identified limiting amino acids in two parenteral nutrition solutions in neonatal piglets.
Recent studies using the indicator amino acid oxidation (IAAO) technique in TPN-fed piglets and infants have been instrumental in defining parenteral amino acid requirements. None of the commercial products in use are ideal when assessed against these new data. Our objectives were to determine whether the oxidation of an indicator amino acid would decline with the addition of amino acids that were limiting in the diets of TPN-fed piglets, and to use this technique to identify limiting amino acids in a new amino acid profile. Piglets (n = 26) were randomized to receive TPN with amino acids provided by Vaminolact (VM) or by a new profile (NP). After 5 d of TPN administration, lysine oxidation was measured using a constant infusion of L- [1-(14)C]-lysine. Immediately following the first IAAO study, the piglets were further randomized within diet group to receive either 1) supplemental aromatic amino acids (AAA), 2) sulfur amino acids (SAA) or 3) both (AAA+SAA) (n = 4-5 per treatment group). A second IAAO study was carried out 18 h later. In the first IAAO study, lysine oxidation was high for both groups (18 vs. 21% for VM and NP, respectively, P = 0.055). The addition of AAA to VM induced a 30% decline in lysine oxidation compared with baseline (P < 0.01). Similarly, SAA added to NP lowered lysine oxidation by approximately 30% (P < 0.01). The application of the IAAO technique facilitates rapid evaluation of the amino acids that are limiting to protein synthesis in parenteral solutions.
Brunton
Janet A
JA
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada, T6G 2P5. jbrunton@mun.ca
Shoveller
Anna K
AK
Pencharz
Paul B
PB
Ball
Ronald O
RO
D000596:Amino Acids / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D024322:Amino Acids, Aromatic / Q000008:administration & dosage; D000603:Amino Acids, Sulfur / Q000008:administration & dosage; D000641:Ammonia / Q000097:blood; D000818:Animals; D000831:Animals, Newborn; D001834:Body Water / Q000378:metabolism; D001835:Body Weight; D004573:Electrolytes; D005947:Glucose; D007202:Indicators and Reagents; D008239:Lysine / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D009751:Nutritional Requirements; D010084:Oxidation-Reduction; D010288:Parenteral Nutrition; D057947:Parenteral Nutrition Solutions; D012996:Solutions; D013552:Swine
D000596:Amino Acids; D024322:Amino Acids, Aromatic; D000603:Amino Acids, Sulfur; D004573:Electrolytes; D007202:Indicators and Reagents; D057947:Parenteral Nutrition Solutions; D012996:Solutions; C545824:amino-acid, glucose, and electrolyte solution; D000641:Ammonia; D005947:Glucose; D008239:Lysine; D009584:Nitrogen