Improvement of nutritional quality of ruminant feed composed of soybean straw and ryegrass hay

Abstract

The purpose of this study was to increase the nutritional value of two raw materials (soybean straw and ryegrass hay), in order to propose the use as feed for ruminants. Different technologies were used to develop the animal feed: addition of proteins, addition of Spirulina platensis biomass, solid state fermentation by Aspergillus niger, encapsulation of microalgae biomass (capsules with xanthan gum and chitosan), as well as the control tests. The chemical composition (moisture, crude protein, lipids, ash, crude fiber, neutral detergent fiber and acid detergent fiber) of the different treatments was determined. Although the solid state fermentation using the fungus Aspergillus niger did not decrease the fiber content, the addition of microalgae biomass in soybean straw and ryegrass hay improved the quality of bulky feed, increasing until 87% and 80% protein content of soybean straw and ryegrass hay, respectively. Furthermore, the addition of Spirulina biomass in soy straw, with gelatin or encapsulated, decreased the content of neutral detergent fiber and acid detergent fiber. The bypass protein obtained using the encapsulated biomass allows the use of agro-industrial waste, adding nutritional value to bulky feed, which may increase the milk production by lactating cows.