Fiber substrates in the nutrition of weaned piglets – a review

The present review summarizes the results of 37 experiments in which different types and levels (from 0.5 to 29.7%) of fibrous supplements were used in the formulation of diets for weaned piglets. Diets were supplemented with different sources of insoluble dietary fiber (iDF), soluble dietary fiber (sDF), or mixed DF sources. Most of the applied DF sources decreased the ileal and fecal organic matter digestibility, and they often lowered crude protein digestibility. A moderate addition (1.5-8%) of iDF sources increased average daily feed intake (ADFI) and, frequently, average daily gains (ADG). Sources of sDF as well as high inclusion levels of fiber-rich feeds tended to decrease ADFI and ADG. Improved fecal consistency, decreased diarrhea incidence and antibiotic interventions were confirmed in piglets fed diets with added lignocellulose, cooked or raw oat hulls and wheat bran. The dietary inclusion of iDF rather than sDF sources improved gastrointestinal tract (GIT) development, enzyme activity and gut morphology. An increase in the counts of beneficial gut microbiota and the concentrations of short-chain fatty acids was stimulated by diets with addition iDF or sDF sources. Such diets also slowed down proteolytic fermentation which negatively affects the colonic mucosa. Some research findings indicate that iDF sources improve intestinal barrier function. The analyzed experimental data suggest that the addition of 1.5-2% of a lignocellulose preparation, 2% of oat hulls, 4-8% of coarse wheat bran to diets for weaned piglets may be recommended to promote GIT development and health, and to improve growth performance.