High-moisture air-tight storage of barley and wheat improves nutrient digestibility

Barley (Hordeum vulgare) and wheat (Triticum aestivum) are often stored dry with 14% or less moisture, which during rainy periods may require that grains are dried after harvest. The hypothesis is that air-tight storage of high-moisture barley and wheat will increase nutrient digestibility due to chemical conversions prior to feeding. The objective was to evaluate the effect of high moisture compared to dry storage of barley and wheat on digestibility of P and CP. The crops were grown on 1 field keeping other factors constant. Half of the grains was harvested in the morning after a rainy day and stored in air-tight silos (DM, %: barley, 85.2; wheat, 82.8) and the other half was harvested later the same day (windy and sunny) and stored dry (DM, %: barley, 89.8; wheat, 88.3). After 6 mo of storage, 1 low- and 1 high-moisture diet were prepared with a barley: wheat ratio of 1:1 mixed with soybean (Glycine max) meal and rapeseed cake to produce a compound diet without inorganic P and microbial phytase. Sixteen 45-kg pigs housed in metabolism crates were fed either the low- or the high-moisture diet for 5 d for adaptation and 7 d for total collection of feces. Digestibility of P was 12% higher (P < 0.01) and of CP was 4% higher (P = 0.08) in the high-moisture diet. Phytase activity of dry-stored grain was lower (P < 0.01) and phytate P was 4% higher in the high-moisture stored grain vs. the grains stored dry. Overall, high-moisture storage increased digestibility of P and CP when the grain was fed to finishing pigs. Therefore, high-moisture air-tight storage saved energy (without drying) and at the same time enhanced P digestibility and increased the nutritional value of grain probably through enzymatic activity during storage.