Metabolism and Nutrition IV: Vitamins and Minerals and Feed Manufacturing

Research on which NRC trace mineral requirements are based was done with inorganic transitional minerals and purified and semi-purified diets. Research with organic trace minerals and standard rations have demonstrated that requirements are much lower than the levels set by NRC, due to the greater availability of these organic minerals. Further, not all organic minerals are the same. Pullets from day-old through a laying cycle were fed diets with conventional inorganic minerals at conventional levels or reduced trace mineral, either as inorganic trace mineral or organic trace minerals (Bioplex® and Sel-Plex®, Alltech, Inc. Lexington, KY). Standard production parameters were recorded. Shell defects, were investigated using optical and electron microscopy. Diet had no effect on pullet growth up to 133 days of age or on average feed intake in the growing phase. Egg production was not significantly affected. Egg weight was significantly reduced in the 4th, 28 day lay period by both reduced mineral levels; in the subsequent periods the conventional mineral levels were significantly different with the Bioplex/ Sel-Plex reduced level being intermediate and not different form either conventional level. Both zinc and manganese levels in the reduced supplement rations were lower in the excreta due to the lower supplement levels; copper and iron were not. This failure to influence copper and iron excretion levels is due to the relatively height endogenous level of these minerals in the basal ration. Level and source influenced shell quality. The number of mottled eggs was not influenced by mineral source or level, while the degree of mottling decreased when organic minerals were used. Streaked eggs (very fine crack-like defects) were not influenced by level or source of minerals.