REMOVAL OF VITAMIN AND TRACE MINERAL SUPPLEMENTS FROM BROILER FINISHER DIETS

In one experiment, supplemental vitamins and trace minerals were remov ed from a 20% CP corn-soybean meal broiler diet during the period 35 t o 42 days posthatching. Vitamin and trace mineral withdrawal reduced d aily weight gain and slightly decreased the bioavailable riboflavin co ntent of breast and thigh muscle. Another experiment involved removal of supplemental riboflavin, only, from broiler diets during the period s 8 to 22, 22 to 42, or 42 to 56 days posthatching. Only during the fi rst period did riboflavin removal reduce weight gain and feed efficien cy. Feeding an 18% CP diet with no supplemental riboflavin during the 42 to 56-day period caused a 43% reduction in bioavailable riboflavin in breast muscle.