Vitamins are complex organic substances, usually of
comparatively small molecular size (molecular weight usually
less than 1000). They are distributed in feedstuffs in small
quantities and form a distinct entity from other major and
minor food components (Cho et a_l., 1985). The importance of
vitamins as essential constituents in the diets of animals
came to light in the early part of this century and during
the past five decades active and rapid progress in vitamin
research was made almost in all the coMmercially important
specie
