Removal of vitamin and trace mineral supplements from broiler finisher diets

In one experiment, supplemental vitamins and trace minerals were removed from a 20% CP corn-soybean meal broiler diet during the period 35 to 42 days posthatching. Vitamin and trace mineral withdrawal reduced daily weight gain and slightly decreased the bioavailable riboflavin content of breast and thigh muscle. Another experiment involved removal of supplemental riboflavin, only, from broiler diets during the periods 8 to 22, 22 to 42, or 42 to 56 days posthatching. Only during the first period did riboflavin removal reduce weight gain and feed efficiency. 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.