title: Involvement of food intake and amino acid catabolism in the branched-chain amino acid antagonism in chicks.
abstract: The role of food intake and branched-chain amino acid (BCAA) catabolism in the branched-chain amino acid antagonism was investigated. A diet containing crystalline amino acids as the sole source of amino acids was formulated to contain adequate levels of all required nutrients. The basal diet contained 0.60% isoleucine, 0.82% valine and 1.2% leucine. Increasing dietary leucine to 5.0% resulted in reduced food consumption, weight gain, and efficiency of food utilization. These effects were prevented by increasing dietary isoleucine and valine to 0.80 and 1.07%, respectively. When L-[1-14C]isoleucine or L[1-14C]valine were included in the diet, the amont of 14CO2 exhaled was increased within 24 hours of feeding the 5% leucine diet. The excretion of 14C was unaffected by leucine. It was determined by force feeding that approximately 70% of the reduced growth rate in chicks fed the leucine-supplemented diet ad libitum could be accounted for by reduced food intake. A portion of the growth depression may be due to increased BCAA catabolism, limiting the availability of valine and isoleucine for growth.
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage*; D000597:Amino Acids, Branched-Chain / Q000378:metabolism*; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004032:Diet; D004305:Dose-Response Relationship, Drug; D006128:Growth / Q000187:drug effects; D007532:Isoleucine / Q000008:administration & dosage / Q000378:metabolism; D007930:Leucine / Q000009:adverse effects*; D008297:Male; D014633:Valine / Q000008:administration & dosage / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000597:Amino Acids, Branched-Chain; D007532:Isoleucine; D007930:Leucine; D014633:Valine