Effect of storage time and processing temperature of grains with added amylolytic enzymes on in situ ruminal starch digestion

Amylolytic exogenous enzymes may increase ruminal digestion of grains. However, stability of enzymes during feed processing can be a constraint for its utilization. Therefore, the objective of this study was to evaluate the efficacy of B. licheniformis amylase and A. niger glucoamylase, according to time of storage after treatment and duration of exposition at 100 C, using corn and sorghum and its effect on in situ ruminal digestibility (12 h incubation) of dry matter and starch. A generalized randomized complete block design was used in the assays, using the block x treatment interaction as the error term. Ruminal starch digestibility (%) was not affected by either time (1, 4, 7, 15 and 30 days) of aspersion before incubation or by the time (0.5, 3, 5, 10 and 15 min) of enzyme exposition at 100 C. It was concluded that both amylolytic thermostable enzymes have the potential as a feed additive to improve ruminal digestibility of corn and sorghum, and are stable at low humidity conditions, which may facilitate its incorporation with grains during feed processing.