^a Presumes an energy density of 3.5 kcal ME/g DM (metabolizable energy/gram dry matter), as determined in accordance with Regulation PF9, which is based on the 'modified Atwater' values of 3.5, 8.5, and 3.5 kcal/g for protein, fat, and carbohydrate (nitrogen-free extract, NFE), respectively.

Rations greater than 4.0 kcal/g should be corrected for energy density; rations less than 3.5 kcal/g should not be corrected for energy.

Rations of low-energy density should not be considered adequate for growth or reproductive needs based on comparison to the Profiles alone.

^b Although a true requirement for fat per se has not been established, the minimum level was based on recognition of fat as a source of essential fatty acids, as a carrier of fat-soluble vitamins, to enhance palatability, and to supply an adequate caloric density.

^c Because of very poor bioavailability, iron from carbonate or oxide sources that are added to the diet should not be considered as components in meeting the minimum nutrient level.

^d Because of very poor bioavailability, copper from oxide sources that are added to the diet should not be considered as components in meeting the minimum nutrient level.

^e Because processing may destroy up to 90 percent of the thiamin in the diet, allowance in formulation should be made to ensure the minimum nutrient level is met after processing.