Degradation of cell-wall monosaccharides of chemically treated grape branches by rumen microorganisms

Summary Freshly pruned grape branches were treated with ozone and sodium hydroxide and the effect of treatments on cell wall chemistry and degradability, was studied. Ozonation was expressed in a dissolution of cell wall (CW) components; lignin and matrix carbohydrates were mainly affected and reduced by 44 and 26% respectively. Notwithstanding, the NaOH treatment in creased the proprotion of total cell wall sugars. The distribution of total sugars in untreated grape branches was: 81.5% in CW and 18.5% in cell solubles. The in vitro digestibility by rumen microorganisms of grape branches organic matter, was low (28%) and was increased by, 111% with ozone, whereas NaOH proved ineffective. Ozone increased the in vitro digestibility of CW-glucose by 174%. The possibility of using grape branches as a raw material for conversion to a ruminant feed is discussed.