Diet nutrient digestibility and growth performance of weaned pigs fed wheat dried distillers grains with solubles (DDGS)

Biofuel co-products such as wheat distillers dried grains and solubles (DDGS) are used increasingly in swine feed to reduce feed cost. Wheat DDGS is rich in protein and phosphorus, thus may replace soybean meal (SBM) in swine diets. To explore, the effects of increasing inclusion of wheat DDGS by substituting SBM on diet nutrient digestibility and growth performance of young pigs were evaluated. In total, 160 pigs (initial BW: 12.5 ± 1.8 kg) were involved in a 3-week trial. Five pelleted wheat-based diets including 0, 50, 100, 150 or 200 g wheat DDGS/kg in substitution for up to 200 g SBM/kg were fed. Diets were formulated to provide 9.8 MJ net energy (NE)/kg and 1.16 g standardised ileal digestible (SID) lysine/MJ NE. Diets were balanced for NE by increasing canola oil inclusion and for amino acids (AA) by increasing crystalline AA. Each 50 g/kg increase in dietary inclusion of wheat DDGS linearly reduced (P < 0.001) the apparent total tract digestibility coefficient (CATTD) of dry matter (DM) by 0.008, of gross energy (GE) by 0.009 and of crude protein (CP) by 0.010. Increasing wheat DDGS quadratically decreased (P = 0.01) diet digestible energy (DE) value and quadratically decreased then increased (P = 0.01) diet calculated NE value. Increasing wheat DDGS did not affect average daily feed intake (ADFI) overall or for any week, but linearly decreased (P < 0.01) feed efficiency (G:F) for day 1-7. For the entire trial (day 1-21), each 50 g/kg increase of dietary inclusion of wheat DDGS up to 200 g/kg linearly reduced (P < 0.05) ADG by 8.5 g/d and G:F by 0.007. In conclusion, weaned pigs fed diets with increasing inclusion of up to 200 g wheat DDGS/kg and supplemental AA to replace SBM had reduced G:F due to reduced ADG, but maintained feed intake.