Alleviatory Effects of Individual Essential Amino Acids on Reduced Performance Induced by Dietary Excess Methionine in Broilers.

Abstract

The alleviatory effect of essential amino acids on growth depression and elevation of plasma methionine (Met) concentration caused by dietary excess Met was studied. Eight-day-old female broiler chicks were divided into 10 groups of 4 chicks with same average body weight and fed each diet containing 0.45 (control) or 1.20% Met diet (excess) for 10 days. To the Met excess diet, 0.4% of individual amino acid, i.e. arginine, glycine (Gly), isoleucine, lysine, threonine (Thr), leucine, valine, or phenylalanine was added. Performance of chicks fed the Met excess diet decreased to 80% of the control group. Lowered performance of chicks fed the Met excess diet was recovered to 90% of the control group by Thr or Gly supplementation to the diet. Plasma concentration of Met increased from 78 to 272 nmol/ml by feeding Met excess diet, but those of Gly, serine and Thr did not change by dietary excess Met. A negative relationship was obtained between plasma Met concentration and body weight gain. The elevated plasma Met concentration was reduced to 63% that of the Met excess diet by Gly and Thr supplementation.