The natural vitamin contents of feeds can obviously vary greatly depending
upon the ingredients used. The major factors affecting natural vitamin contents
are choice of cereal and choice of protein source. Among the cereals,
wheat and maize are the most widely used on a global basis, and they have
very different values for some vitamins. Animal proteins and oilseed meals
can also have widely differing contents of some vitamins.
To illustrate the effects that diet ingredient composition can have on dietary
vitamin contents, Table 4 shows the vitamin contents for broiler prestarter
and starter diets based mainly on wheat or maize, using animal or
oilseed meal proteins, and for diets containing other ingredients. Considera-