Acid steeping of corn and grain sorghum: effect on nutrient digestibility in growing pigs

Abstract Two experiments were conducted to determine the effect of acid steeping of whole corn and grain sorghum on nutrient digestibility in growing pigs. In the first experiment, corn and cream, yellow and bronze sorghum hybrids were steeped in a 0.25% sulfurous acid solution (corn for 48 h at 52 °C and sorghum for 24 h at 48 °C) after which the steeping solution was discarded. Digestibility of diets containing the grains was measured with 48 barrows (27.5 ± 2.1 kg). Steeping increased dry matter (DM) and energy digestibility of corn-based diets, but had little effect or a negative effect on the digestibility of sorghum-based diets (grain × steeping interaction, P n ) contents (the latter corrected for nitrogen balance) than yellow and cream sorghum ( P In the second experiment, corn and yellow and bronze sorghum hybrids were steeped in a 0.3% sulfurous acid, 0.1% lactic acid solution for 0, 12, 24 or 48 h. Steeping solution was discarded after steeping. Digestibility was measured with 72 barrows (36.8 ± 4.0 kg). In general, steeping for either 12 or 24 h reduced digestibility of corn and grain sorghum. However, 48 h of steeping did not affect digestibility in comparison with non-steeped grains, especially for corn and yellow sorghum (steeping time quadratic, P P P n contents than diets containing yellow sorghum. Steeping corn and grain sorghum without recovery of soluble or suspended substances from the steeping solutions resulted in little improvement in nutrient digestibility.