Effects of washing procedure and dilution ratio on the size of non-washout, insoluble washout, and soluble washout fractions in concentrate ingredients

A widely adopted procedure to characterize degradation in the rumen is the in situ incubation technique (IS), that assumes the washout fraction of feeds (W) to be equal to the soluble (S) fraction and that both are rapidly and completely degraded which may not be the case. Because IS technique is unable to measure the rate at which the W fraction is actually degraded; therefore, alternative washing procedures need to be developed to recover and fractionate the W fraction. Recently, simple washing procedure have been developed at Lelystad (method M) (Melin et al, unpublished results) and at Wageningen (method AA, SM and Y) (Azarfar et al., 2004; Yang et al., unpublished results), by which the feeds can be fractionated in a non-washout (NWF), an insoluble washout (ISWF) and a soluble washout fraction (SWF). The aims of this study were: 1-To study the effect of different washing procedures on the size of NWF, ISWF and SWF in some concentrate ingredients. 2- To study the effect of different dilution ratios (5, 10, 20, 30 and 40) on the size of SWF, and soluble true protein (STP) in some concentrates ingredients.