Effects of hydroxycinnamic acids (Ferulic and p-coumaric acids) in barley cultivars on cell wall components degradability in rumen

Massoumeh Suodkolae,Yadollah Chashnidel,Teimouri Yansari

doi:10.2298/bah1703271s

Abstract

Barley grain contains hydroxycinnamic acids especially Ferulic (FA) and p-Coumaric acid (pCA) become cross-linked to cell wall polysaccharids as lignification commences that are the major inhibiting factors of biodegradability of plant cell walls in the rumen. Chemical characteristics, FA and pCA content of 11 Iranian barley cultivars determined. Using 3 fistulated ewes, the effects of FA and pCA content on ruminal degradation of dry matter (DM), neutral and acid detergent fiber (NDF and ADF) and lignin were studied. In barley cultivars, DM varied from 82.52 to 90.90 %; NDF varied from 9.64 to 27.34 % DM; ADF varied from 2.03 to 8.13 % DM and lignin varied from 0.87 to 3.03 % DM. The FA content ranged from 151.2 to 354.2 ?g/g; and pCA content ranged from 114.5 to 444.4 ?g/g of DM. Ruminal degradation parameters for DM, NDF, ADF and lignin were different between barley cultivars. The soluble fraction, slowly degradable, potential degradable, and undegradable fraction of DM were 2.92 to 56.33%; 42.64 to 91.45%; 65.68 to 98.97%, and 1.02 to 34.31%, respectively. The rate of ruminal degradation for DM varied among barley cultivars from 3.64 to 27.81% h-1. The FA was related to rumen indigestible DM, NDF, ADF and lignin, while pCA correlated with ADF. Using multi-regression, FA and pCA were inhibiting factors of ruminal degradability for DM and cell wall components; and FA was the most effective factor to predict DM degradability, while both FA and pCA affected NDF and ADF ruminal degradability.

Highlights

Increasing corn prices resulted in using more barely grain as main starch sources in dairy cattle rations
Chemical compositions The dry matter (DM) level of the barley grain cultivars used in the present study was lower than those reported by Ghorbani and Hadj-Hussaini (2002) who showed that the DM level of 10 barley grain cultivars ranged from 92 to 94 %
The NDF, ADF and acid detergent lignin (ADL) concentrations of the barley grain cultivars used in the present study had more variance than those of reported by Du et al (2009), that examined six Canadian barley varieties and reported NDF, ADF and ADL values varied from 17.6 to 21.9, 5.5 to 7.0 and 1.7 to 2.1 %DM

Summary

Introduction

Increasing corn prices resulted in using more barely grain as main starch sources in dairy cattle rations. Barley grain contains predominant phenolic compounds or low molecular weight hydroxycinnamic acids including FA and pCA (Hernanz et al 2001). The rate and extent of ruminal degradation of plant cell wall is negatively impacted by complex components such as lignin, cellulose, lignin-carbohydrate, and phenolic-carbohydrate, as well as FA and pCA is believed to be the major inhibiting factors to the ruminal biodegradability of plant cell walls (Yu et al 2005). The cell walls polysaccharids become cross-linked to monolignols via Hydroxycinnamic acids as lignification commences (Santiago et al 2006). Increases in dimeric and monomeric compound content following exposure to light were reported. These compounds influence the mechanical properties of the cell walls, such as rigidity during plant growth (Miyamoto et al 1994). The relative abundance of lignin and the frequently of phenolic compounds cross-links with

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