Abstract

SEGURA S, Freimar; ECHEVERRI F., Rosario; PATINO LL, Arley C.  and  MEJIA G., Amanda I.. DESCRIPTION AND DISCUSSION ABOUT THE METHODS OF ANALYSIS OF FIBER AND OF THE NUTRITIONAL VALUE OF FORAGES AND FOODS FOR ANIMALS. Vitae [online]. 2007, vol.14, n.1, pp.72-81. ISSN 0121-4004.

In order to improve the agroalimentary chain and to diminish the extensive use of land to grow crops for cattle raising, there is a need for greater availability of forages with adequate nutritional value. Biotechnological processes to improve grass by fermentation with basidiomycetes, are an alternative. However, it is difficult to determine the changes that take place in forage with the fermentation process. There are many reports on techniques to evaluate forage components. Of them, the detergent system is the most frequently used but more modern methods are also available. Accesibility and costs of the latter are limiting factors for many laboratories and some of the newer methods have not yet been officially approved. We describe and discuss the detergent system to evaluate the nutritional value of foods for ruminants, and the difficulties of its interpretation. In the analysis of forages exposed to biodegradation processes, we concluded that values of lignin and cellulose (van Soest system) found in blanks and specimens do not correspond to the real contents of these substances in the biodegraded specimen. More precise methods should be used such as IRTF spectroscopy (infrared with transformed of Fourier) or near infrared (NIRS) to characterize these specimens.

Keywords : Fiber; food analysis; van Soest scheme; Weende system of analysis.

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