Abstract
A study was conducted to determine the effects of the period of predigesting whole stillage (WS; slurry material that is dried into DDGS) with multi-enzyme and composition of the multi-enzyme on porcine in vitro digestibility of dry matter (IVDDM) of the WS. Four samples of whole stillage from 4 different sources were freeze-dried and divided into 13 subsamples to give 52 sub-samples. Thirteen treatments were applied to the 48 sub-samples within source. The treatments were undigested WS (control); or pre-digested with 1 of 3 multi-enzymes (MTE1, MTE2, and MTE3) at 55 °C for 6, 12, 18 or 24 h in 3 × 4 factorial arrangement. The MTE1 contained xylanase, β-glucanase, cellulase, mannanase, protease, and amylase; MTE2 contained xylanase, α-galactosidase, and cellulase; and MTE3 contained xylanase, cellulase, β-glucanase, and mannanase. The 52 subsamples were subjected to porcine in vitro digestion. The IVDDM of untreated WS was 73.3%. The IVDDM increased (P< 0.05) with an increase in the predigestion period. However, a rise in the predigestion period from 0 to 12 h resulted in greater (P< 0.05) response in mean IVDDM than an increment in the predigestion period from 12 to 24 h (11 vs. 0.83 percentage points). Predigestion period and multi-enzyme type interacted on IVDDM such that the improvement in IVDDM between 0 and 12 hours of predigestion differed (P< 0.05) among the 3 multi-enzyme types (13.3, 11.1, and 8.5 percentage points for MTE3, MTE2, and MTE1, respectively). The LS means by multi-enzyme treatment were modeled and resulted in unparallel curves (P< 0.05). The estimated maximum response of IVDDM for MTE1, MTE2 and MTE 3 were 82.4%, 84.7% and 87.1% at 15.8, 13 and 13.1 hours, respectively. In conclusion, the optimal time of predigestion of WS with multi-enzymes (with regard to improvement in its IVDDM) was approximately 14 h.
Production of Methane, Hydrogen and Ethanol from Secale cereale L. Straw Pretreated with Sulfuric Acid
