title: Glutamate promotes nucleotide synthesis in the gut and improves availability of soybean meal feed in rainbow trout.
abstract: Glutamate (Glu) plays various roles directly or through conversions to other amino acids in intracellular metabolisms such as energy source for enterocytes and precursor for nucleic acids. In this study, we examined the effect of single and chronic oral administration of Glu on cell proliferation in intestine and growth in rainbow trout fed soybean meal (SBM) based diet. In the single dose study, 30, 120 and 360 min after oral administration of 50 and 500 mg/kg Glu, the blood and intestine tissues were collected for amino acid concentration and gene expression analysis. Cell-proliferation was detected 24 h after administration using bromo-deoxy uridine (BrdU) in intestine. In the chronic experiment, fish were fed SBM-based diet added 1 and 2 % of Glu for 8 weeks. Final body weight, plasma amino acid concentrations, gene expression and cell-proliferation in the intestine were analyzed. The expressions of some nucleic acid-synthesis related genes were significantly increased 30 min after administration of 50 mg/kg of Glu. After 8 weeks of feeding, the fish fed SBM-based diet showed significantly lower body weight and microvillus thickness in proximal intestine. Supplementation of 2 % of Glu in the SBM-based feed improved both of them. Though it was not significant difference, Glu tended to increase cell-proliferation in the proximal intestine dose-dependently in both single and chronic administration. Our experiment indicates that Glu has positive effect on rainbow trout fed SBM-based feed by reforming proximal intestine through altering cell-proliferation.
authors.affiliation: Frontier Research Labs, Institute for Innovation, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kanagawa 210-8681 Japan ; Strategy Implementation Group, Business Strategy and Planning Department, Ajinomoto Animal Nutrition Group, Inc., Tokyo, 104-0031 Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Yoshida
authors.affiliation: Material Development and Application Labs, Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kanagawa 210-8681 Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Maekawa
authors.affiliation: Frontier Research Labs, Institute for Innovation, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kanagawa 210-8681 Japan.
authors.forename: Makoto
authors.identifier: 0000-0001-5081-2929
authors.initials: M
authors.lastname: Bannai
authors.affiliation: Feed Group, Tamaki Laboratory, National Research Institute of Aquaculture, Fisheries Research Agency, Tamaki, Mie 519-0423 Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamamoto
keywords: Amino acids; Feed ingredient; Fishmeal alternatives