In situ ruminal degradation of phenolic acid, cellulose and hemicellulose in crop brans and husks differing in ferulic and p-coumaric acid patterns

SUMMARYLignification-associated phenolic acids are widely distributed in graminaceous plant cell walls. Nylon bags containing maize bran, wheat bran, millet husk and rice husk were incubated in the rumens of five Charolais (♂) × Nanyang (♀) crossbred steers for 6, 12, 24, 36, 48 and 72 h. The in situ ruminal disappearance of ester-linked phenolic acids linearly increased in the brans with increasing incubation time, and the disappearance was greater for ester-linked ferulic acid (FAest) than for ester-linked p-coumaric acid (PCAest). The disappearances of FAest and PCAest were positively correlated with disappearances of neutral detergent fibre (NDF), cellulose and hemicellulose. The effective degradabilities of NDF, cellulose and hemicellulose in the brans were markedly greater than the effective degradabilities of these components in the husks, and were negatively correlated with the contents of Lignin (sa), ether-linked ferulic acid, PCAest and ether-linked p-coumaric acid in both the cereal brans and husks. These findings suggested that breeding forage crops with modified phenolic acid contents could represent an alternative strategy to promote further increases in fibre digestibility of cereal residue feeds for ruminant animals.