Corn coproducts produced from the fuel ethanol or the wet milling industries may be used in diets fed to pigs. Newly developed corn proteins are high protein feed ingredients with approximately 40 to 50% crude protein (CP), and corn protein may be a great source of digestible amino acids (AA) in diets fed to weanling pigs. There are, however, limited data on the digestibility of AA in different sources of corn protein fed to weanling pigs. Therefore, the objective of this experiment was to test the null hypothesis that there is no difference in the standardized ileal digestibility (SID) of AA in 3 different sources of corn protein when fed to weanling pigs.

Experimental design

Eight barrows (initial BW: 11.09 kg; SD = 0.46 kg) with a T-cannula installed in the distal ileum were allotted to 1 of the 4 diets using a replicated 4 × 4 Latin square design with 4 diets and 4 periods of 7 days in each period. Therefore, there were 8 replicate pigs per diet. Three sources of corn protein were procured: 1) new corn protein, 2) ANDVantage 50 Y, and 3) ANDVantage 40 Y (Table 1). ANDVantage 50 Y and ANDVantage 40 Y were sourced from The Andersons, Wichita, KS.

Three diets contained each corn protein source as the sole source of AA and an N-free diet was used to determine the basal endogenous loss of AA. Each experimental period lasted 7 days. The initial 5 days of each period were considered an adaptation period. Ileal digesta were collected on day 6 and 7 for 8 hours using standard procedures. The diets and ileal digesta were analyzed for AA and Cr to calculate the apparent ileal digestibility of CP and AA in the 3 sources of corn protein. The apparent ileal digestibility values were then corrected using the basal endogenous losses of CP and AA to calculate the SID values.

Results

The SID of Ile, Phe, Val, Ala, Asp, Ser, and Tyr was the greatest (P < 0.05) in ANDVantage 50 Y, followed by ANDVantage 40 Y and the new corn protein (Table 2). The SID of Arg, His, Lys, Met, Thr, Cys, Glu, and Gly in ANDVantage 50 Y was greater (P < 0.05) than in the other 2 sources of corn protein, but no difference in these SID values was found between ANDVantage 40 Y and the new corn protein. The SID of Leu in ANDVantage 50 Y and ANDVantage 40 Y was greater (P < 0.05) compared with the new corn protein and the SID of Trp in ANDVantage 50 Y was greater (P < 0.05) than in the new corn protein.

Key points

• A new source of corn protein contains similar crude protein and less amino acids compared with ANDVantage 50 Y, but contains greater crude protein and amino acids compared with ANDVantage 40 Y.
• Values for the standardized ileal digestibility of crude protein and most amino acids in the new sources of corn protein were less than in ANDVantage 50 Y.
• Values for the standardized ileal digestibility of crude protein and Ile, Leu, Phe, Val, Ala, Asp, Ser, and Tyr in the new sources of corn protein were less than in ANDVantage 40 Y, but the standardized ileal digestibility of Arg, His, Lys, Met, Thr, Trp, Cys, Glu, Gly, and Pro was not different between the 2 sources of corn protein.

Table 1. Nutrient composition in 3 sources of corn protein, as-is basis

Table 2. Standardized ileal digestibility of AA in 3 sources of corn protein¹

^a-cWithin a row, means without a common superscript differ (P < 0.05).

¹Values for SID were calculated by correcting the values for apparent ileal digestibility for basal ileal endogenous losses. Basal ileal endogenous losses were determined (g/kg of DMI) as CP, 21.73; Arg, 0.75; His, 0.25; Ile, 0.49; Leu, 0.76; Lys, 0.60; Met, 0.12; Phe, 0.46; Thr, 0.77; Trp, 0.22; Val, 0.66; Ala, 0.86; Asp, 0.94; Cys, 0.26; Glu, 1.27; Gly, 2.03; Pro, 5.86; Ser, 0.58; and Tyr, 0.38.