Fiber ruminants: Nutritional, methodological and functional aspect

Abstract

The fiber is an essential component and one of the main items in diet of ruminants, and their physical and chemical characteristics can directly affect the digestive physiology in the rumen. In the practice, the fiber in the balance of diets given different terms, according with their solubility and degradation characteristics. These terms, including FB (crude fiber), NDF (neutral detergent fiber) and ADF (acid detergent fiber), NDF being more related to structural carbohydrates (cellulose, hemicellulose and pectin), which is more used to interfere in the diet utilization by animal, their quantity can stimulate or inhibit food intake by ruminants. Based on the physical characteristics of NDF two new concepts were developed: physically effective NDF (peFDN) related to particle size and effective NDF (eFDN) related with the ability of food in maintained the percentage of fat in milk. The FDA refers to cellulose, lignin, silica and protein, and is used to estimated the hemicellulose by subtraction of ADF from NDF. The fiber stimulates chewing, serves as substrate for microorganisms, contribute to maintenance of the fermentative standards and rumen ambient stability. Thus, the fiber in diet of ruminants when not available in quantity and quality at animals may compromise the performance and interfere in the final products characteristics, yonder cause disturbances in the energy metabolism of animals.