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.