Corn coproducts produced from the ethanol industry are often used in diets for pigs. A new source of corn protein (NexPro; Flint Hills Resources, Wichita, KS) has been developed, but at this time there is limited information about the nutritional value of this new source of corn protein. Therefore, the objective of this experiment was to test the hypothesis that the standardized ileal digestibility (SID) of amino acids  in corn protein is greater than in 2 sources of distillers dried grains with solubles (DDGS; i.e., DDGS-1 and DDGS-2) when fed to growing pigs.

Experimental design

Eight growing pigs (initial BW: 37.13 ± 2.44 kg) with a T-cannula installed in the distal ileum were allotted to a replicated 4 × 4 Latin square design with 4 diets and 4 periods. There were 2 pigs per diet in each period for a total of 8 observations per treatment. Experimental diets were based on each of the 2 sources of DDGS or corn protein as the sole source of amino acids. A nitrogen-free diet was used to measure the basal endogenous losses of amino acids. Each experimental period lasted 7 d. The initial 5 d of each period was considered an adaptation period. Ileal digesta were collected on d 6 and 7 for 8 h using standard procedures. Diets and ileal digesta samples were analyzed for amino acids and chromium to calculate the apparent ileal digestibility (AID) of amino acids in DDGS and corn protein. The AID values were corrected for basal endogenous losses of crude protein and amino acids to calculate SID values.

Results

The concentration of crude protein and amino acids were greater in corn protein compared with DDGS-1 and DDGS-2 (Table 1). The AID and SID of crude protein and most amino acids were greater (P < 0.05) in DDGS-2 and corn protein compared with DDGS-1 (Table 2). Although the SID of crude protein and amino acids in corn protein were not different from DDGS-2, corn protein had greater concentrations of amino acids than DDGS-2. As a result, corn protein contained more standardized ileal digestible amino acids than DDGS-1 and DDGS-2.

Key points

• A new source of corn protein contains more crude protein and amino acids compared with DDGS.
• The AID and SID of AA in corn protein are equal to or greater than in DDGS.

Because of the greater amino acids concentration, corn protein contains more standardized ileal digestible amino acids compared with DDGS.

Table 1. Crude protein and amino acid composition of corn protein and 2 sources of distillers dried grains with solubles (DDGS)

Table 2.  Apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in corn protein and 2 sources of distillers dried grains with solubles (DDGS)¹

^a-cValues within a row lacking a common superscript letter are different (P ≤ 0.05).

¹Data are least squares means of 8 observations per treatment.

²Standardized ileal digestibility values were calculated by correcting values for apparent ileal digestibility for the basal ileal endogenous losses. Basal ileal endogenous losses were determined as (g/kg dry matter intake): crude protein, 17.85; Arg, 0.68; His, 0.16; Ile, 0.29; Leu, 0.46; Lys, 0.32; Met, 0.07; Phe, 0.27; Thr, 0.48; Trp, 0.09; Val, 0.43; Ala, 0.56; Asp, 0.69; Cys, 0.14; Glu, 0.79; Gly, 1.61; Ser, 0.46; and Tyr, 0.22.