153 Standardized ileal digestibility of amino acids and concentration of metabolizable energy in three sources of corn protein fed to weanling pigs

Abstract Two experiments were conducted to test the hypothesis that the standardized ileal digestibility (SID) of amino acids (AA), apparent total tract digestibility (ATTD) of gross energy (GE), and concentrations of digestible energy (DE) and metabolizable energy (ME) are not different among three sources of corn protein (i.e., new corn protein, ANDVantage 50Y, ANDVantage 40Y) when fed to weanling pigs. In Exp. 1, ileal-cannulated barrows [n = 8; initial body weight (BW) = 11.09 kg; SD = 0.46] were fed an N-free diet or three diets containing each corn protein as the sole source of AA. Pigs were allotted to a replicated 4 × 4 Latin square design with 4 diets and 4 periods of 7 d in each square. Ileal digesta were collected for 2 d and the SID of AA was calculated. In Exp. 2, weanling pigs (n = 32; initial BW = 18.0 kg; SD = 1.21) were fed a corn-based basal diet or three diets containing corn and each source of corn protein. Pigs were housed individually in metabolism crates and feces and urine were quantitatively collected for 5 d after 7 d of adaptation. Concentrations of DE and ME in all diets were calculated and DE and ME in the three sources of corn protein were calculated by difference. Data from both experiments were analyzed using the MIXED procedure of SAS with pig as the experimental unit. In Exp. 1, the statistical model included diet as the fixed effect and square, pig, and period as random effects. In Exp. 2, the model included ingredient as the fixed effect. Results from Exp. 1 demonstrated that the SID of all indispensable AA except Arg and His in ANDVantage 40Y and ANDVantage 50Y were greater (P < 0.05) compared with the new corn protein, but no differences were observed between ANDVantage 50Y and ANDVantage 40Y (Table 1). Results from Exp. 2 indicated that on a dry matter basis, concentration of DE in ANDVantage 50Y was greater (P < 0.05) than in ANDVantage 40Y, the new corn protein, and corn, but ME in ANDVantage 50Y was not different from the ME in the new corn protein (Table 2). Concentration of ME in the new corn protein was not different from ME in corn, ANDVantage 40Y, or ANDVantage 50Y. In conclusion, the new source of corn protein had concentrations of AA that were not different from ANDVantage 50 Y, but this new corn protein had decreased digestibility of AA compared with other corn proteins. The new corn protein also had less DE compared with ANDVantage 50Y, but ME in the new corn protein was not different from corn, ANDVantage 40Y, or ANDVantage 50Y.