Effects of Monosodium Glutamate and Aminogut on Nursery Pig Performance

Research indicates that dietary addition of AminoGut (product combining glutamine and glutamate; Ajinomoto Heartland, LLC, Chicago, IL) improves nursery pig performance; however, it is unknown whether the response is due to glutamine, glutamate, or their combination. In a 42-d study, 1,134 nursery pigs (PIC 359×1050, 4.9 kg BW) were used to determine the effects of monosodium glutamate (MSG), glutamine (Gln), or AminoGut on growth performance. Pigs were fed 6 dietary treatments in 2 phases from d 0 to 7 and 7 to 21 post-weaning. Treatments included a control diet, or the control with 0.5, 1.0, or 1.5% MSG, a combination of 1.0% MSG and 0.4% glutamine fed in both phases, or 0.8 and 0.6% AminoGut fed in phase 1 and 2, respectively. A common diet was fed from d 21 to 42. Pigs were assigned to pens at weaning and pens were assigned to treatment in BW blocks in a randomized complete block design with 7 replicate pens/treatment. Data were analyzed using Proc Mixed with pen as experimental unit. Linear and quadratic response to MSG was tested. Mean separation was used to determine response to Gln and AminoGut. During phase 1, there was no evidence for difference (P>0.453) for ADG, ADFI, or G:F with the addition of MSG, AminoGut, or MSG+Gln. There was no evidence feeding MSG improved ADG or ADFI (P>0.163) in phase 2, but marginally improved (linear, P=0.094) G:F. Pigs fed AminoGut had improved ADG (P<0.05) compared with all other treatments and increased (P<0.05) ADFI compared with pigs fed 0.5, 1.0, or 1.5% MSG. Feeding AminoGut resulted in improved (P<0.05) G:F compared with 0, 0.5, or 1.0% MSG, or MSG+Gln. There was no evidence for differences (P>0.105) during the common period or overall. There was no evidence feeding MSG alone or with Gln improved post-weaning growth performance; however, feeding AminoGut enhanced growth and feed efficiency from d 7 to 21 post-weaning compared with pigs fed the control diet.

	Control	0.5% MSG	1.0% MSG	1.5% MSG	MSG+Gln	AminoGut	SEM
Phase 1 (d 0 to 7)
ADG, g	33	20	23	26	33	21	8.14
ADFI, g	182	195	190	190	193	191	5.64
G:F	0.178	0.105	0.120	0.128	0.171	0.107	0.0433
Phase 2 (d 7 to 21)
ADG, g	262b,c	251c	262b,c	263b,c	271b	296a	7.5
ADFI, g	398a,b	370c	388b,c	384b,c	399a,b	416a	9.5
G:F	0.657b	0.678b	0.677b	0.684a,b	0.679b	0.711a	0.0118
a,b,cMeans with different superscripts differ P<0.05.