Effects of dietary fibers on mineral status of chicks.

We investigated the effects of replacing dietary starch with dietary fibers of various types and particle sizes on utilization of bivalent cations by chicks. Inclusion of polyethylene powder, alfalfa cell walls, corn bran, oat bran and wheat bran into diets resulted in lower serum and tibia Zn levels. However, addition of pectin, cellulose and a xylose:gum arabic (50:50) mixture did not affect tissue Zn levels, whereas addition of 4% lignin increased serum Zn level from 2.50 to 3.44 micrograms/ml. Ingestion of fibers with particle sizes less than 300 micrometers resulted in higher serum Zn levels compared with those of particle sizes greater than 300 micrometers. Incorporation of 4 and 8% pectin decreased (P less than 0.05) serum and tibia Mg levels. When brans were fed, kidney Mg levels were lower due to fiber additions. Inclusion of lignin, the xylose:gum arabic mixture and alfalfa cell walls resulted in lower liver Cu levels; polyethylene and solka floc had no effect on liver Cu status. Fiber did not affect tissue Ca or Fe status. Each mineral influenced by fiber type, level or particle size appeared to be affected through different mechanisms.