The role of fiber in swine feeding

Abstract

In many studies on the utilization of dietary fiber by pigs, the utilization of fiber itself and its effect on the digestibility and other dietary components have been assessed using crude fiber as the component representing dietary fiber. However, depending on the relative contents of cellulose, hemicellulose, pectins and lignin, crude fiber almost always represents only part of the real fiber intake of the animal. Thus, depending on the source and, hence, chemical composition of the fiber used, measurements based on crude fiber may lead to inaccurate estimations of the apparent digestibility of dietary fiber. Both the amount and the type of dietary fiber significantly influenced the apparent digestibility of dietary dry matter, nitrogen and energy. The digestibility of neutral detergent fiber (NDF) and of their components are markedly affected by the type and the amount of fiber in the diet, so, crude fiber (CF) ranged from 25% to 66% in different sources. Increased NDF intakes were associated with significantly higher wet weights of all gastrintestinal segments and increased lengths of the caecum. The number of cellulolytic bacteria for lean genotype was higher than obese genotype. The rate of passage by obese genotype is faster explained the lower digestibility of fiber. When the pig were raised in high temperature environment the apparent digestibility is lower than thermo neutral zone temperature. The practices of the use of fiber in diet needs to take a knowledge about the effect of level fiber on the digesta of protein, energy and minerals as well as the fiber itself. Finally, the cost of feeding represents >60% of the total cost of pig production and energy components constituents the greatest proportion. Therefore, it is important to know the energy value of feeds on an objective basis and to adapt feed supply to energy requirements of animals.