The fibrous food constitutes an important resource for most of animal production systems developed in the tropic. However, its nutritious properties are from medium to low quality, due to its high dry matter and fiber contents and its low contributions in energy, proteins and minerals.

There are not many studies about the characterization of this food and of the actions that can be made to improve its nutritious properties and with it, have a better use for animals. Therefore, the studies directed to this end, have a wide mark of application, given man's determination in increasing the efficiency in the food-animal protein conversion, the reduction of the productive process costs, the non contamination of the atmosphere and the non competition among the dietary sources of animals with human feeding.

The presented work is framed in this context and expresses the main results from 23 experiments that allowed taking a step forward in the knowledge of fibrous fraction structure from important food for the tropic: fresh and fermented cane. It is novel and attractive the contribution carried out to determine its coefficients, structures and physical-chemical property, its influence on physiology and gastrointestinal microbiology of monogastric organisms and the quantification of energy provided through the content of short-chained fatty acids that allows substituting, on technical bases, an important energy food percentage for birds and pigs.

Isolating and characterizing 26 mushrooms stumps, mainly of high hydrophilic value, and obtaining mutants with important levels of enzymatic secretion able to hydrolyze the lignocellulosic bonds, will allow increasing food nutritious efficiency and therefore, closing the technological cycle with a more effective system for birds and pigs.

The results gave rise to a diploma, a doctorate and 3 works in scientific events: 2 Seminars in the Institute of Animal Science (ICA) and 1 Pan-American Seminar of Veterinary Sciences in 1998.