Oral administration of MSG increases expression of glutamate receptors and transporters in the gastrointestinal tract of young piglets.
Glutamate receptors and transporters, including T1R1 and T1R3 (taste receptor 1, subtypes 1 and 3), mGluRs (metabotropic glutamate receptors), EAAC-1 (excitatory amino acid carrier-1), GLAST-1 (glutamate-aspartate transporter-1), and GLT-1 (glutamate transporter-1), are expressed in the gastrointestinal tract. This study determined effects of oral administration of monosodium glutamate [MSG; 0, 0.06, 0.5, or 1 g/kg body weight (BW)/day] for 21 days on expression of glutamate receptors and transporters in the stomach and jejunum of sow-reared piglets. Both mRNA and protein levels for gastric T1R1, T1R3, mGluR1, mGluR4, EAAT1, EAAT2, EAAT3, and EAAT4 and mRNA levels for jejunal T1R1, T1R3, EAAT1, EAAT2, EAAT3 and EAAT4 were increased (P < 0.05) by MSG supplementation. Among all groups, mRNA levels for gastric EAAT1, EAAT2, EAAT3, and EAAT4 were highest (P < 0.05) in piglets receiving 1 g MSG/kg BW/day. EAAT1 and EAAT2 mRNA levels in the stomach and jejunum of piglets receiving 0.5 g MSG/kg BW/day, as well as jejunal EAAT3 and EAAT4 mRNA levels in piglets receiving 1 g MSG/kg BW/day, were higher (P < 0.05) than those in the control and in piglets receiving 0.06 g MSG/kg BW/day. Furthermore, protein levels for jejunal T1R1 and EAAT3 were higher (P < 0.05) in piglets receiving 1 g MSG/kg BW/day than those in the control and in piglets receiving 0.06 g MSG/kg BW/day. Collectively, these findings indicate that dietary MSG may beneficially stimulate glutamate signaling and sensing in the stomach and jejunum of young pigs, as well as their gastrointestinal function.
Key Laboratory of Agroecology Processes in Subtropical Region, Institute of Subtropical Agriculture Research Center, Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Chinese Academy of Science, Ministry of Agriculture, Furong Road #644, Changsha City, 410125, Hunan, China.
Jun
J
Zhang
Yulong
Y
Yin
Xu Gang
XG
Shu
Tiejun
T
Li
Fengna
F
Li
Bie
B
Tan
Zhenlong
Z
Wu
Guoyao
G
Wu
D000284:Administration, Oral; D000818:Animals; D001692:Biological Transport; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D050491:Glutamate Plasma Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D017470:Receptors, Glutamate / Q000235:genetics* / Q000378:metabolism; D012970:Sodium Glutamate / Q000008:administration & dosage / Q000378:metabolism*; D013552:Swine / Q000254:growth & development / Q000378:metabolism*
D050491:Glutamate Plasma Membrane Transport Proteins; D017470:Receptors, Glutamate; D018698:Glutamic Acid; D012970:Sodium Glutamate