title: Regulation of free glutamate content in meat by dietary lysine in broilers.
abstract: Regulation of taste is important for improving meat quality and glutamate (Glu) is one of the important taste-active components in meat. Here, the effects of dietary lysine (Lys) content on taste-active components in meat, especially free Glu, were investigated. Fourteen-day-old broiler chicks (Gallus gallus) were fed on diets containing 100% or 150% of the recommended Lys content for 10 days. Concentrations of free amino acids in plasma, muscle and liver were measured. The levels of messenger RNAs (mRNAs) for enzymes related to Glu metabolism were determined in muscle and liver. The concentration of muscle metabolites was also determined. The free Glu content in muscle of chicks fed the Lys150% diet was increased by 44.0% compared with that in chicks fed the Lys100% diet (P < 0.01). The mRNA level of lysine α-ketoglutarate reductase, which is involved in Lys degradation and Glu production, was significantly increased (P < 0.05) in the Lys150% group. Metabolome analysis showed that the Lys degradation products, muscular saccharopine, pipecolic acid and α-aminoadipic acid, were increased in the Lys150% group. Our results suggest that free Glu content in muscle is regulated by Lys degradation. These results suggest that a short-term feeding of high-Lys diet could improve the taste of meat.
authors.affiliation: Graduate School of Science and Technology, Niigata University, Niigata, Japan.
authors.forename: Genya
authors.initials: G
authors.lastname: Watanabe
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shibata
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kubota
authors.forename: Motoni
authors.initials: M
authors.lastname: Kadowaki
authors.forename: Shinobu
authors.initials: S
authors.lastname: Fujimura
mesh_terms: D015074:2-Aminoadipic Acid / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D019587:Dietary Supplements; D005260:Female; D063427:Food Quality; D018698:Glutamic Acid / Q000032:analysis* / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008239:Lysine / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000378:metabolism; D008460:Meat / Q000032:analysis*; D009132:Muscles / Q000378:metabolism; D010875:Pipecolic Acids / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012443:Saccharopine Dehydrogenases / Q000235:genetics / Q000378:metabolism
chemical_list: D010875:Pipecolic Acids; D012333:RNA, Messenger; D015074:2-Aminoadipic Acid; D018698:Glutamic Acid; D012443:Saccharopine Dehydrogenases; C031345:pipecolic acid; D008239:Lysine; C100169:saccharopine
keywords: amino acid; dietary lysine; glutamic acid; metabolism; muscle