The major limitations of using these residues as ruminant feeds are low content in their nutrients such as protein content and vitamins and they are rich in fibers with low digestibility, or law palatability and high lignin contents. The degree of lignifications is relatively more important in controlling hydrolysis rate in animal digestive tract. Therefore, chemical and biological treatments are used for increasing the nutritional value of many by-products, because they have significant concentrations of simple carbohydrates, such as mono-and disaccharides. For these reasons the chemical and...