A new source of corn protein (NexPro) that is produced from the ethanol industry has been developed by Flint Hills Resources (Wichita, KS). NexPro contains approximately 50% crude protein and the digestibility of amino acids was reported in our November, 2020, Newsletter. However, there is at this time no information about the concentration of digestible energy (DE) and metabolizable energy (ME) in this new source of protein. Therefore, the objective of this experiment was to test the hypothesis that concentrations of DE and ME in corn protein are 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

Thirty-two growing pigs (initial BW: 16.50 ± 0.90 kg) were allotted to a completely randomized design with 4 diets and 8 replicate pigs per diet. Pigs were housed individually in metabolism crates that were equipped with a self-feeder, a nipple waterer, and a slatted floor. A screen and a urine pan were placed under the slatted floor for the total, but separate, collection of urine and fecal samples. A basal diet containing corn as the sole source of energy and 3 diets containing corn protein and each source of DDGS were formulated. Feed consumption was recorded daily and pigs were fed experimental diets for 12 d with urine and fecal samples being collected during the final 5 d according to standard procedures using the marker to marker approach. At the conclusion of the experiment, fecal and urine samples were analyzed and concentrations of DE and ME in each diet and in each ingredient were calculated.

Results

Concentrations of crude protein and gross energy were greater, whereas acid-hydrolyzed ether extract and insoluble dietary fiber concentration were less, in corn protein compared with DDGS-1 and DDGS-2 (Table 1). Corn had the greatest (P < 0.01) apparent total tract digestibility of gross energy, but corn protein had greater (P < 0.01) apparent total tract digestibility of gross energy compared with DDGS-1 and DDGS-2. Corn protein also had greater (P < 0.01) DE and ME than corn, DDGS-1, and DDGS-2. Calculated on a dry matter basis, the ME in corn protein were not different from corn, but corn protein and corn had greater (P < 0.01) DE and ME compared with DDGS-1 and DDGS-2.

Key points

• A new source of corn protein contains more gross energy than DDGS.
• Corn protein also has greater concentrations of DE and ME than DDGS

Table 1. Nutrient composition of corn, corn protein, and 2 sources of distillers dried grains with solubles (DDGS)

Table 2. Concentration of digestible energy (DE) and metabolizable energy (ME), and apparent total tract digestibility (ATTD) of gross energy in corn, corn protein, and 2 sources of distillers dried grains with solubles (DDGS)¹

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

^a-dMeans within a row lacking a common letter are different (P ≤ 0.01).