This research examined variation in chemica
l composition and nutrient qua
lity of soybeans (SBs)and soybean mea
ls (SBMs) produced at seven commercia
l extruder/expe
ller p
lants in the UnitedStates (experiment 1), as we
ll as differences in amino acid digestibi
lities when roosters were fedSBMs extruded at 121, 135, 150, or 160
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C at a U.S. pi
lot processing p
lant (experiment 2). Inexperiment 1,
limited variation existed in the composition of SBs arriving at the p
lants, whereassubstantia
l differences were noted in amino acid composition and protein qua
lity of the resu
ltantSBMs. In experiment 2, the SBMs extruded at 121 and 135
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C were underprocessed as noted byhigh urease activities and
lower amino acid digestibi
lities. Soybean mea
ls extruded at 150 and 160
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C resu
lted in higher amino acid digestibi
lities and
lower urease activities, indicating adequateprocessing. Large variation exists in the nutritiona
l qua
lity of extruder/expe
ller SBMs current
ly in themarketp
lace. Optima
l processing temperatures shou
ld be >135
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C, and temperatures as high as165
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C do not resu
lt in overprocessing.