IMPACT OF METHYL 5-O-(E)-FERULOYL-ALPHA-L-ARABINOFURANOSIDE ON IN-VITRO DEGRADATION OF CELLULOSE AND XYLAN

The potential for inhibition of ruminal cell wall degradation by soluble phenolic acid-carbohydrate complexes was assessed using a synthetic molecule, methyl 5-O-(E)-feruloyl-alpha-L-arabinofuranoside (FA-Ara). In-vitro 24 and 72 h degradabilities of glucose from microcrystalline cellulose, and neutral sugars and uronic acids of oat spelts xylan were determined. Treatments included 0 (Control), 15, 150, 1500, and 4500 mumol liter-1 of methyl alpha-L-arabinofuranoside (Me-Ara), FA-Ara, or ferulic acid (FA). Additions of 1500 and 4500 mumol liter-1 Me-Ara; 15 and 150 mumol liter-1 FA-Ara; as well as 4500 mumol liter-1 FA significantly (P < 0.05) decreased 24 h cellulose degradation. Arabinose degradation from xylan after 24 h was decreased (P < 0.05) by 1500 and 4500 mumol liter-1 concentrations of Me-Ara and FA-Ara. No inhibitory effects of added compounds on 72 h glucose, xylose, or arabinose degradability were observed. Very little FA-Ara remained intact after 24 h. Following 72 h, no added FA-Ara was detectable, suggesting extensive degradation by microbial feruloyl esterases. Extent of polysaccharide degradation, in vitro, was not limited by a soluble phenolic acid-carbohydrate compound, which accurately models a known cell wall complex.