Screening of exogenous enzymes for ruminant diets: relationship between biochemical characteristics and in vitro ruminal degradation.

摘要: With the objective of developing a rational approach for selection feed enzymes ruminants, 22 commercial enzyme products were examined in terms protein concentration, enzymic activities on model substrates, and hydrolytic capacity, latter determined from release reducing sugars alfalfa hay corn silage. An vitro ruminal degradation assessment was carried out using same untreated or treated with at 1.5 microL/g forage DM. Stepwise regressions then performed to establish relationships between these factors. Protein concentration explained least 84% (P < 0.01) variation Alfalfa DM after incubation fluid 18 h positively related xylanase activity (R2 = 0.29, P 0.01), but negatively silage 0.19, 0.05). Protease further 10% 0.10). Following sequential steps involving determination rate extent fiber degradation, best candidates selected. Enzyme effective seemed exert part their effect during pretreatment period, whereas worked exclusively added. This finding suggests that different modes action exogenous are attacking substrates may partly explain enzyme-feed specificity. In alfalfa, it seems work by removing structural barriers retard microbial colonization digestible fractions, increasing degradation. silage, seem interact degrade more rapidly, which is consistent previous findings synergism enzymes.