Rumen degradation kinetics of alfalfa hay, maize silage and wheat straw treated with fibrolytic enzymes

In situ disappearance kinetics of alfalfa hay, maize silage and wheat straw treated with three enzyme mixtures were studied. The objective was to evaluate three commercial enzyme products, mainly used in poultry nutrition, for ruminants. The products were Cellupract AS 130, Natuzyme and Endofeed DC, mixtures of different enzyme activities to break down non-starch polysaccharides present in the plant cell wall (mainly s-glucanase, xylanase and cellulase). Nylon bags containing forage, treated and control, were incubated in duplicate for 4, 8, 16, 24, 48, 72 and 96 h in the rumen of two Blochi ewes fitted with rumen fistula. All treatment and control forage samples were evaluated in terms of their dry matter (DM) and crude protein (CP) degradation characteristics. Forages showed different (p<0.01) DM and CP rumen degradation kinetics. For DM, enzyme treatment significantly (p<0.01) increased the rapidly soluble fraction a, the potentially degradable fraction b, and effective degradability (ED). Cellupract AS 130 affected DM degradability to a greater extent (p<0.01) than the other enzymes, and increased (p<0.05) fractional degradation rate (parameter c) and ED of forage protein compared with the control forages. The other enzymes had only a slight effect, and the increase in some degradation parameters compared with control was significant only in a few cases with Endofeed. Fibrolytic enzyme mixtures, in particular Cellupract, could be used as ruminant feed supplements to enhance forage digestibility.