Digestibility of silages in relation to their hydroxycinnamic acid content and lignin composition.
BACKGROUND
The effectiveness of the analysis of cell wall-bound hydroxycinnamic acids and the composition of lignin to evaluate the in vivo digestibility of a silage collection with unknown botanical composition was evaluated.


RESULTS
Syringyl units content and total etherified phenols showed the highest correlation coefficients with in vivo dry matter digestibility (IVDMD) (r = - 0.792 and r = - 0.703, respectively), while guaiacyl units and total phenols showed the highest correlation coefficients with in vivo organic matter digestibility (IVOMD) (r = - 0.871 and r = - 0.817, respectively). Using the above-mentioned chemical parameters, 10 equations were also developed to predict in vivo digestibility. The prediction of IVDMD produced a high adjusted R(2) value (0.710) using syringyl, total lignin, etherified total phenols, esterified ferulic acid and total phenol content as predictors. The prediction of IVOMD produced a higher adjusted R(2) value (0.821) using guaiacyl, total phenols, total ferulic acid and etherified p-coumaric acid content as predictors.


CONCLUSIONS
Cell wall digestibility depends on a multiplicity of factors and it is not possible to attribute a causal effect on in vivo digestibility to any single factor. However, syringyl and guaiacyl content and etherified phenols emerge as good predictors of digestibility.
Taboada
Alfredo
A
CIA de Mabegondo-INGACAL, E-15080 A Coruña, Spain.
Novo-Uzal
Esther
E
Flores
Gonzalo
G
Loureda
Maria
M
Ros Barceló
Alfonso
A
Masa
Antón
A
Pomar
Federico
F
D000818:Animals; D002473:Cell Wall / Q000737:chemistry*; D002934:Cinnamates / Q000032:analysis*; D003373:Coumaric Acids / Q000032:analysis; D004043:Dietary Fiber / Q000032:analysis; D004063:Digestion; D008031:Lignin / Q000737:chemistry*; D008297:Male; D010636:Phenols / Q000032:analysis*; D011422:Propionates; D012756:Sheep; D012820:Silage / Q000032:analysis*
D002934:Cinnamates; D003373:Coumaric Acids; D004043:Dietary Fiber; D010636:Phenols; D011422:Propionates; C029010:cinnamic acid; D008031:Lignin; C004999:ferulic acid; C495469:p-coumaric acid